GeoscienceIssues

Reducing greenhouse gas emissions

CO2capture

and geologicalstorage

The BRGM series “Geoscience Issues”Director of the series:

Jacques VaretEditorial board:

ADEME : Agnès Heyberger, Arnaud Mercier.BRGM : Isabelle Czernichowski-Lauriol, Pierre Vassal.

IFP : Pierre le Thiez, Patrick Boisserpe.With the participation of the departments and divisions of ADEME, BRGM and IFP.

Editorial staff: Martine Castello, Michel Bouchi-Lamontagne.Translation: Jody Mohammadioun and Rowena Stead

Design and production: BL Communication.Printing: Imprimerie Nouvelle

ISBN ADEME : 2-86817-800-6 ISBN BRGM : 2-7159-0970-5 ISBN IFP : 2-901638-10-4All rights reserved. May be reproduced in part after explicit permission.

ISSN pending. Copyright September 2005.

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The carbon cycle, like that of water, plays a major role in the daily lifeof our planet Earth. One characteristic of its components is that theyare intrinsically involved in both geological and atmosphericphenomena.What is more, they form essential building blocks for alllife forms, the human race included. Under these conditions, mankind,as responsible beings, must devote a minimum amount of attentionto the effects the choices made for its development are liable to have,particularly when the said effects become so far-reaching that theybegin to weigh heavily on the great natural balances underlying the Earth's system.

Throughout its eventful geological history, our planet has been led to store within itself - or more precisely in its outermost solid shellknown as the lithosphere - vast quantities of carbon compounds.These primarily take two forms: carbonates, on the one hand, foundthe world over and used extensively (as building stone, industrialminerals, cement, among many others), and fossil fuels, on the other.Although resources of the latter are less abundant, they aresufficiently widespread to have been consumed in huge quantitiesfrom the very beginning of the industrial era, whether as solids (coal, lignite, peat, or bituminous shale), liquids (oil or bitumen) orgases (natural gas, CO2).

The end of the 20th Century marks a milestone. Humanity hasdeveloped to such a point, both demographically and technologically,as to have a profound impact on the biological and physical naturalenvironments. Meanwhile, our understanding of the planet and ofinteractions between its solid, liquid and gaseous spheres hasprogressed thanks to research conducted in geology, geophysics,meteorology and space.This comes not a minute too soon: virtuallyat the same time as mankind has succeeded in extracting such a large proportion of fossil resources that the peak of thehydrocarbon depletion curve is within sight, it has also discovered theharmful and irreversible effects on climate associated with the gases

released into the atmosphere by this massive extraction of carbonfrom its natural underground repository.

The Climate Convention signed by 166 nations following the 1992Earth Summit held in Rio de Janeiro reflects the political awareness of these climate-related risks. An agreement was reached concerningthe need for mankind to reduce its greenhouse gas emissions into theatmosphere. But the Kyoto Protocol that stemmed from it, althoughconcluded in 1997, only came into effect in February 2005, and eventhen un-signed by one of the principal nations concerned by suchemissions, the United States. Moreover, fast-growing economies suchas China, India or Brazil, not to mention the developing countries,who also have the right to use fossil fuels to spur their development -even if this is beyond their grasp for the time being - will alsocontribute to the swelling greenhouse gas emissions.

Under these circumstances, mankind's pursuit of development,if it is to be sustainable and durable, will require mobilizing allavailable technological options capable of ensuring modes of energyproduction and consumption that are both judicious and do notemit greenhouse gases. Insofar as it is not prepared to forego the useof fossil fuels - even in favour of a 'hydrogen-based society' - ourcivilization will be obliged to find 'clean' means for usinghydrocarbons, natural gas and coal.

Geological storage currently emerges as the only option that renderscompatible the continued use of fossil fuels with maintaining climateconditions suitable for mankind.What it actually comes down to is sending the carbon 'back home', i.e. returning it to the lithosphere,to prevent its altering the composition of the atmosphere.

Michèle Pappalardo Philippe Vesseron Olivier AppertChief Executive Officer Chairman Chairman

of ADEME of BRGM of IFP

Foreword

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• Our Planet is growing warmer . . . . . . . . . . . . . 4• Global mobilization is imperative . . . . . . . 6• The willpower to act . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8• CO2 capture and storage:

towards a cleaner use of fossil fuels . . 10

• Where can we capture CO2? . . . . . . 14• How can we capture CO2? . . . . . . . . . . 15• How can we transport CO2? . . . . . . . 17

• Performance and costof the technologies . . . . . . . . . . . . . . . 34

• Developing decision-supporttools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

• A technology to be developed . . . . . . . . . . . . . . . . . . . . . . 35

• France's commitment . . . . . . . . . . 40

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. . . . 33

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Fertilizer plant

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• Where can such vast amounts be stored? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

• Progress and experience . . . . . . . . . . . . . . . . . . . . . . . 22• Storage in deep aquifers . . . . . . . . . . . . . . . . . . . . . . . 24• Storage in oil and gas reservoirs . . . . . . . . 26• Storage in coal seams . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28• Mineral sequestration . . . . . . . . . . . . . . . . . . . . . . . . . . . 30• Controlling long-term impacts . . . . . . . . . . . . .31

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A pressing situationIt will no longer come as a surprise to anyone thatthe Earth is warming abnormally. Since thebeginning of the industrial era, its temperature hasincreased by an average of 0.6° C, and sea level has risen by between 10 and 20 cm. Already we arefeeling the first negative consequences: chaoticweather, flooding, heat waves, droughts, the meltingof glaciers, rising sea level and changes in plant and

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by 31%. True, the amount of CO2 released by man (30 billion tons per year, equivalent to 8.1 billiontons of carbon) accounts for only a smallproportion of the total annual carbon cycle, butthe natural CO2 sinks* - the biosphere and theoceans - absorb only half this amount. Theremainder accumulates year after year in theEarth's atmosphere, upsetting the climate'ssensitive mechanisms. If we fail to do anything, ordo not do enough, experts are predicting a meantemperature increase of 2 to 6° C by 2100, togetherwith a rise in sea level ranging from 9 to 88 cm,along with all the related negative consequences.

The greenhouse effectA thin layer of gas surrounds our planet like ablanket, holding in a portion of solar radiation. Thisphenomenon, termed “greenhouse effect,” isresponsible for the fact that, throughout history,the planet's average temperature has alwaysremained compatible with life. Without thegreenhouse effect, the Earth's temperature wouldbarely reach -18° C! Thus on Mars, which lacksgreenhouse gases (but which is also farther fromthe sun), the temperature is -50° C. Nor is lifepossible where the greenhouse effect is too strong.Venus, with its carbon-dioxide-rich atmosphereand a surface temperature of 420° C, is a primeexample of this. So the Earth is an exception in oursolar system, an exception that favours theevolution of life-forms and human consciousness.But for more than a century, human activity has

animal life. The guilty parties, identified by a largemajority of specialists worldwide, are the so-called“greenhouse gases” (GHG*), in particular carbondioxide (CO2*), responsible for some 55% of man-induced greenhouse effect. Produced in largequantities by human activities such astransportation, buildings and industry, this gas isessentially given off when fossil fuels - coal, oil or gas- are burned. Over the past century, greenhouse gasconcentrations have risen by 50% and that of CO2

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*See Glossary at the end.

The rapid economic growth experienced in the past century was in large part based onfossil carbon (oil, gas and coal) extracted massively from its natural undergroundrepository and released into the atmosphere as CO2.

Models are predicting a rise in sealevel ranging from 9 to 88 cm

between now and 2100 due to thethermal expansion of the upper

layers of the oceans and themelting of glaciers.

The evolution of airtemperatures and CO2concentrations over thepast 400 millennia:the planet's mean temperature hasfollowed a curve parallel to that ofCO2 concentrations in theatmosphere. But since 1750, CO2concentrations have increasedrelentlessly (+31%), reaching todaya level of 365 ppmv (parts permillion by volume).

An uneasy balanceThe biosphere and the oceans are capable at present of absorbing half the surplusCO2 produced by human activity. But the CO2 sinks* - such as forests and oceans -would appear to have their limits. According to the Intergovernmental Panel onClimate Change (IPCC*), a saturation phenomenon may exist. Coupled with anincrease in temperature, this could result in a sudden and massive release of CO2into the atmosphere and thereby amplify the phenomenon instead of partially con-trolling it.

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The natural carbon cycleCarbon's natural cycle plays an essential part in the greenhouse effect. The fourteenth mostabundant component of our planet, carbon iseverywhere in our environment. It is uniqueamongst the elements in terms of the variety ofsubstances it is capable of forming. It can be foundin the atmosphere as CO2 or methane, dissolved in seawater, stored in organic matter (plants, wood,fossil fuels, etc.) and in rocks as carbonates. Carbondioxide is drawn from the atmosphere by plants,bacteria and micro-plankton through the processof photosynthesis.These organisms absorb the carbon found in CO2and give off oxygen. The opposite process occursduring respiration or the decomposition of organic

3.5 billion tonsof surplus carbon!

Global CO2 emissions linked to man's activitiesamount to 30 billion tons (Gt) per year,

corresponding to 8.1 Gt of carbon:6.5 Gt (or 80%) are derived from burning fossil fuels,while 1.6 Gt (or 20%) are the result of deforestation

and agricultural practices.These man-induced emissions are only partially

absorbed by CO2 sinks: 2.5 Gt by the oceansand 2 Gt by vegetation.

And so, each year, 3.5 Gt of carbonend up accumulating in the atmosphere

and upsetting the climate.

matter. Respiration absorbs oxygen and releasesCO2 into the atmosphere. This cycle, if undisturbedby human activity, allows a balanced carbon budgetto be maintained on the planet, since the volume ofCO2 released into the atmosphere is equal to thattaken up by vegetation. The system is likewiseinfluenced by phytoplankton and the ocean, whichabsorb CO2 through photosynthesis or dissolution:this has enabled the Earth to keep a balancedcarbon budget over the centuries, despite volcaniceruptions and deforestation. But with the advent ofthe industrial era, these natural cycles have beendisturbed by human activities that extract carbonfrom the subsurface in the form of hydrocarbons orcoal and release it into the atmosphere aftercombustion.Today, scenarios for climate evolution are still poorlyconstrained because the carbon cycle calls complexmechanisms into play. These are at work in bothcontinental and marine environments, where thechemical, biological and inorganic reactions

been disturbing the balance between theincoming solar energy and that which is radiatedback into space. And if we stand idly by, thesituation will worsen yet further: since CO2remains in the atmosphere for some one hundredyears, the gas produced today will still be around a century from now, maybe even more.

involved are closely intertwined. Now that we arejust beginning to investigate and understand thesemechanisms, many queries remain unanswered,notably concerning the recycle time for CO2 byoceans and the biomass. One thing is certain,however: the climate is getting warmer, and theprocess will intensify if we do nothing to cut back on our emissions.

Evolution of the Rhône glacier inSwitzerland photographed

in 1850, 1910 and 1985.Climate, too, is affected

(droughts, hurricanes …).

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©CNRS, A.R. Devez© CNRS, X. Leroux© Ed. Otto Süssli© Ed. Photo. Gabler© F. Von Martens

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© PolfotoCO2 is responsible for some 55% of man-induced greenhouse effect.

1850 1910 1985

Arrhenius's intuition The idea has been around for over a century! In 1895,Arrhenius (1859-1927), scientist and Nobel prize winnerin chemistry, explained before his colleagues of theSwedish Academy of Science that water vapour andCO2 play a major role in the Earth's thermal balance.He quite logically deduced that the intensive use offossil fuels was liable to enhance the greenhouseeffect. A century went by before his warning wasfinally heeded internationally in the political arena.Indeed, only recently has a consensus been reachedamongst the international scientific communityconcerning global warming - and especially man'sinfluence. Previously, the models were not robustenough to verify Arrhenius's intuition. He was onlyproven right after much technological progress andthe acquisition of a large mass of data on past climateand on the carbon cycle. In 1988, the creation of theIntergovernmental Panel on Climate Change (IPCC) bythe World Meteorological Organization (WMO) andthe United Nations Environment Programme (UNEP)signals a true turning point.The 2500 scientists dulymandated by the United Nations are responsible forcollecting and summarizing pertinent data. IPCC alsohas the delicate task of coming up with mitigationstrategies. Its reports, published at regular intervals, areviewed today as authoritative. Sadly, they are alsoincreasingly a cause for alarm.

International mobilizationIn March 1989 in The Hague, on the initiative ofFrance, the Netherlands and Norway, 24 heads ofstate made a symbolic commitment to combating6

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the intensification of the greenhouse effect.The Earth Summit (the second United Nationsconference on the environment and development),held in 1992 in Rio de Janeiro, was organized aroundthe same topic. It led to the United NationsFramework Convention on Climate Change(UNFCCC), signed by 166 countries. Its ultimate goalis to stabilize CO2 concentrations in the atmosphere

Signed on 11 December 1997,the Kyoto Protocol came intoeffect on 16 February 2005.It is the only internationalframework that exists to combat the threat of climate change.

at a level precluding any hazardous man-induceddisturbance to the climate system. But this virtuousintention was not followed up by any concretemeasures.However, the Conference of Parties, which is thegoverning body of the Climate Agreement, isexpected to convene at regular intervals in order todefine more precisely its objectives and their

Commitments made by the nations that ratified the Kyoto Protocol.Some forty industrialized nations have committed to reducing their greenhouse gas emissions by an average of 5.2% between 2008 and 2012compared to 1990 levels, meaning an 8% reduction for Europe.

As early as 1895, Swedish scientistSvante Arrhenius predicted that theuse of fossil energy was liable toenhance the greenhouse effect.

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The objectives for the EU-15 Member Statesvary significantly: they range from -21% for

Germany and Denmark to +27% for Portugal or+25% for Greece, and are unchanged

for Finland and France.

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implementation conditions. The decision is taken, forinstance, that only developed countries, whichtogether with China are the main ones responsiblefor the greenhouse effect, will be under theobligation to reduce their emissions.In 1997 in Kyoto, the Parties to the Agreement came countries over the period 2008-2012 compared to

1990 levels. To come into effect, this agreementneeded to be ratified by at least 55 countries,representing 55% of the emissions from developedcountries. The United States' refusal in 2001 tosupport the agreement hindered the process.Russia's signature in 2004, however, infused new lifeinto the Kyoto Protocol and, on 16 February 2005,it finally came into effect.But now, we must strive further. The first IPCC reportindicates that global warming must not exceed 2° C,and that CO2 concentrations must be stabilized at450 parts per million by volume (ppmv*) if majordisasters are to be averted. This objective imposes a greater than 50% reduction in emissionsworldwide which, for industrialized countries, comesdown to cutting back on current figures by a factorof 4 or 5. This challenge presupposes vigorousinternational mobilization. There are no miraclesolutions on offer, only a portfolio of options thatall urgently need to be explored today.

A schematicrepresentation of the concepts involved in the problematics of climate change.A result of greenhouse gasemissions, climate changesimpact both man and hisenvironment.The socio-economic development choicesare expressed either throughprevention and mitigationmeasures (the reduction ofemissions: energy conservation,renewable energy sources, thegeological storage of CO2) or byadaptation policies (theprevention of climate risks:efforts to counter erosion,protection against extremeevents …).Orange arrows indicate the cycleof cause and effect in the fourillustrated sectors; the greenarrow denotes the societalresponse to the effects of climate change.

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�together once again to negotiate quantifiedobjectives for greenhouse gas reduction.At the end of this conference, the historic agreement,which came to be known as the Kyoto Protocol, wassigned: its provisions include a mean 5.2% reductionin the greenhouse gas emissions of developed

Events and key dates in the “climate change” dossier

The fifteen major producers of CO2In this pollution “honour roll,” France counts among the “goodcandidates”. Emissions due to electricity, although significant on aglobal scale, are very low in this country where only 10% of electricityis generated from fossil fuels.

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released into the atmosphere upon combustion, andsteel manufacture uses coal as a reducing agent foriron ore. Aware of these problems, the stakeholdersfrom the steel and cement sectors today areendeavouring to devise new techniques to cut downon the carbon content in their products.

Developing clean, renewableforms of energy A move towards low-carbon fossil energy is asolution widely practiced today. Replacing coal bynatural gas results in a 40% reduction in CO2emissions. Apart from the nuclear sector, whichproduces no CO2 at all and has a major role to play inthe fight against global warming, a number ofrenewable sources of energy can be called upon.Thus, converting solar, wind and hydropower intoelectricity no longer produces any CO2 at all! Francehas accordingly committed itself to generating 20%of its electricity from renewable sources as of 2010,compared with 15% at present. Geothermal energyalso has a role to play. Heat pumps enjoy growingpopularity, and the first power plant using hot andfractured rocks is scheduled to come on-line in 2006at Soultz-sous-Forêts, in the Bas-Rhin Département.In the transport sector, programmes have beenlaunched at European and national scale to inventcleaner fuels and high-performance engines.European automobile manufacturers havecommitted themselves to measures that areexpected to procure significant reductions in CO2

Increasing energy efficiencyThe combat against climate warming begins with achange in behaviour, both individual and collective(urban planning, land-use planning, transportsystems, commercial logistics, etc.). A veritablewealth of savings is to be had through improvedenergy use in housing, construction, transportationand industry, in quantities that should certainly notbe underestimated. In the home, adopting energy-saving appliances (Class A or B refrigerators andwashing machines) cuts back on consumption by upto 50%; savings from installing double glazingrepresent 7%, an energy-efficient boiler 14 to 16%,wall insulation 10 to 15%, roof insulation 10 to 20%,an individual solar-powered water heater or heatpump up to 70%, a programmable room thermostat5 to 8%, and so the list goes on. Concerning cars,better maintenance of the air filter reduces gasconsumption by 10%, smooth driving 5 to 15%, theuse of “green” low-consumption tyres 4%.It is possible to cut down on carbon emissions at theproduct design stage. For example, by reducing thethickness of aluminium foil or sheets of paper inpackaging, the amount of energy required tomanufacture them is reduced accordingly. Inconstruction, cement and steel can be replaced bywood, thereby ensuring reforestation. The limestoneused to produce cement contains carbon that is

CO2 emissions of a typicalFrench household

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emissions per kilometre travelled, falling from 190 g/km in 1997, to 140 g/km in 2008, with a targetof 120 g/km set for 2012. In some thirty French cities,dedicated-fleet vehicles, notably in public transport,are already powered by a mixture of diesel fuel andmethyl esters from vegetable oils. These esters,otherwise known as bio-diesel, are also sold in gasstations in mixtures up to 5% with conventionaldiesel. Ethanol, another bio-fuel produced mainlyfrom sugar-beets and wheat, can be used directlytoday in gasoline engines in the form of a derivative(ETBE) mixed with gasoline in concentrations of upto 15%. Great hopes are currently founded onhydrogen fuel cells since the resource is boundless,and the only by-product of hydrogen combustion iswater vapour. The difficulty lies in extractinghydrogen at low cost and without polluting, andthen exploiting it under satisfactory safetyconditions, whether in storage or distribution.

Our everyday lifestyle (heating, electricity…) is the source of almostone-quarter of greenhouse gas emissions, yet it is possible to changeour day-to-day habits.

The house of the future:Design adapted to the use of efficient appliances allowing

the reduction of energy bills and expensesfor the running of such equipment.

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Bio-diesel will be intensively developed in order to achieve the European recommendation of 5.75% incorporated into motor fuels by 2010.

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CO2 capture and storage Despite the wide variety of alternative measuresbeing proposed to combat greenhouse effect (energyconservation, clean transport, renewable sources ofenergy, etc.), CO2 capture at the source and itsgeological storage constitutes another vital approachto reducing global warming. Actually, this entailsreturning to the subsurface, as CO2, part of thecarbon extracted from it as hydrocarbons or coal.More than one-third of CO2 emissions in the worldare produced by concentrated sources such as powerstations, cement plants, refineries and steel mills,which will continue to run on fossil fuels. Limiting the

impact of these emissions will depend onimplementing techniques for capturing, transportingand storing CO2.Today, this rapidly expanding sectorrepresents a temporary solution while awaiting theadvent of new, pollution-free forms of energy.

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Using a geothermal heat pump allows savings of up to 60%over conventional electric heating bills.

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Windmills convert the wind's kinetic energy into more practical forms of energy, notably mechanical energy or electricity.

Geothermal energy at Soultz-sous-Forêts in Alsace:water injected into 5000-m-deep wells converts to steam inhot and fractured rocks,allowing electricity to begenerated.

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The French Climate PlanTo boost the National Programme to combat climate change (PNLCC -programme national de lutte contre le changement climatique), the 2004Climate Plan encompasses today all aspects of national policy concerning cli-mate change. Drawn up with the participation of the concerned stakeholders,this Plan combines the measures implemented to combat greenhouse effectacross all sectors of the economy and daily life in France.The Plan pledges to save54 million carbon-equivalent tons per year by 2010.The Plan is geared around eight initiatives: a public-awareness campaign on environ-mental issues, promoting eco-housing, natural air conditioning, sustainable agriculture, new energy sources, reducinggreenhouse gases in industry, rendering the public sector exemplary, and promoting forecasting research in this area.In a market economy context, the Plan relies on demand from consumers with environmental priorities and on supplyfrom manufacturers committed to tradeable emission permits, energy certificates and profitable investment insustainable development.Coupled with this plan, a National Observatory for the Effects of Climate Change (ONERC) is being established to study fore-seeable consequences of climate warming, including flooding,severe storms and drought,and to prepare to cope with them.

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For over a decade, many companies across all activity sectors havetaken their own steps towards reducing negative impacts on the

environment. AERES (an Association of firms for reducinggreenhouse effect) was founded in September 2002 on theinitiative of French companies who voluntarily committed

themselves to limiting their emissions of greenhouse gases.Originally composed of 20 companies, the association's

membership has now grown to 34, together with four professionalfederations, and jointly represents 60% of the greenhouse gas

emissions from French industry.

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Trapping CO2 at the sourceIn this context, amongst the various solutionsproposed, the notion of trapping CO2 at the sourcewherever possible is clearly an urgent need.Long-term research is being undertaken today tofunnel CO2 away from the atmosphere: the lines ofinvestigation include fixation as a stable compoundto form carbonates by means of a natural process,bio-fixation of CO2 through photosynthesis in micro-algae and using CO2 to produce methane thanks tomethanogenic bacteria. The most promising researchdeals with the capture and geological storage of CO2.This gas must be retrieved where it is beingproduced in large quantities, as is the case forindustrial smoke stacks, which spew forth 30% of theworld's CO2, and then be re-injected underground.This being a novel concept, major research projectsdid not get off the ground until the early 1990's.From the outset, however, the geological storage of

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A world still dominated by fossil energy Many energy scenarios are regularly constructed bynational and international institutions, like theInternational Energy Agency (IEA), the U.S.Department of Energy (DOE), the EuropeanCommission and the World Energy Council (WEC),and by industry (Shell). All agree on one point: in the

time-frame of 2020-2030, worldwide energydemand will continue to grow, and energy derivedfrom fossil sources - gas, oil and coal - will still satisfy80% of the demand. Even if oil reserves in allprobability become harder to find and to tap, fossilfuels will still hold a dominant position insofar asthe other energy sources available are not yet readyto replace them.A sharp decrease in the global energy budget cannotbe counted on in the medium term to ensureareduction in greenhouse gases. Is it really possible forhumanity to hold back its development and refrainfrom burning two-thirds of an energy that is bothaccessible and relatively inexpensive? According toIEA, by around 2030, CO2 emissions will alreadyexceed 37 million tons per year. Extrapolating this to 2100, if no counter-measures are instituted, amean temperature increase of between 2 and 6° Cmust be expected, although the extent of associatedenvironmental and human consequences are hard to predict.

Fossil fuel productionworldwide and the CO2concentration in theatmosphere

Since the beginning of theindustrial era, the consumptionof fossil fuels grew rapidly, tothe point that for some ofthem (oil, gas) depletion is nowin sight. Between 2010 and2040, once the peak is past,production should begin itsrelentless decline (green andred curves). As to coal (blackcurve), the peak comes lateryet and should not beexpected for several decades,or even two centuries.At the same time, the carbondioxide emitted by burningthese fossil fuels results in anincrease in the greenhouse gasconcentrations in theatmosphere.Whether or notwe succeed in stabilizing theseemissions in or around 2040(blue curves) will depend onthe efforts made by producersand consumers to reduce therate of increase of theseemissions.

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CO2 capture at the Warrior Run plant in Cumberland, Maryland (USA).

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case, the gas may be transported as a low-temperature liquid.In pipelines, the CO2 is either in a dense phase,subjected to pressures in excess of 74 bars (a supercritical state) or in liquid form. Whateverthe case, CO2 transport entails its dehydration andcompression, and the presence of impurities isliable to hinder the process. Transport by pipelineis already in common use in the United States.Nevertheless, the different infrastructure optionsavailable will have to be increased considerably in order to satisfy demand.

The first European industrial pilot for flue gas capture is to be installed on the coal-burning Esbjergværket power stationin Denmark. The pilot's expected capacity will be aboutone ton of CO2 per hour.

CO2 can be conveyed by gas pipelines similarto those used for natural gas,

as here with reinforcementof the Guyenne feeder in France.

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CO2 was situated in an international framework, aspart of the International Energy Agency's“greenhouse gas” programme (IEA-GHG), and IPCCwill be publishing a report on this topic by the end of 2005. Research efforts in this area are growing in number and scale, and are viewed withconsiderable interest by the scientific, industrial and political communities. Currently, a number ofmajor research poles on this subject can beidentified: Europe, Australia, Canada, the UnitedStates and Japan. Many exchanges take placeamong the teams involved.

Capturing CO2Power stations, cement plants, refineries, steel millsand other industrial facilities are responsible for overone-third of CO2 emissions worldwide. These largestationary sources of pollution are directly concernedby CO2 capture. The main difficulty resides inseparating CO2 from the other constituents presentin the flue gas, such as water vapour and nitrogen.The techniques operational today are relatively costlyand are based on three different principles:• The first retrieves the CO2 diluted in combustion

flue gas (post-combustion capture).• The second consists in using pure oxygen rather

than air during combustion in order to obtainconcentrated CO2 (oxy-fuel combustion capture).

• The third seeks to extract the CO2 at the source bytransforming the fossil fuel into a H2 + COsynthesis gas* prior to use (pre-combustioncapture).

Transporting CO2Various techniques are available to convey CO2from its point of capture to the storage site. Inview of the volume that needs to be moved, theonly possible options for the large-scale transportof this gas are pipelines and shipping. In the latter

Exploring all optionsChannels other than geological storage are alsobeing examined today in order to divert CO2from the atmosphere.Of these, CO2 fixation as a stable substance toform carbonate rocks using a natural mineral-ization process is the one under closest scrutiny.CO2 bio-fixation through photosynthesis inmicro-algae is a pilot project in the UnitedStates and has attracted the attention of theInternational Energy Agency. The process con-sists in incorporating, into a bioreactor, CO2from industrial sources and nutrients requiredto grow algae, which are products of high com-mercial value.A last orientation for research aims to usemethanogenic bacteria to produce natural gas:certain types of bacteria are actually capable ofreducing CO2 into methane.

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Storing CO2 at depth Once captured, the CO2 has to be stored in deepgeological formations over long periods that maylast several centuries, whilst ensuring safety. Themain options available for geological storage are:

• storage in deep aquifers* offers the highestpotential in terms of capacity and geographicaldistribution; experts assess the storage capacity inaquifers at several trillion tons;

• storage in depleted oil and gas reservoirs, anoption all the more attractive since CO2 injectioncan enhance the recovery of additional oil;

• storage in coal seams in deposits that have not yetbeen worked: the injection can be associated with

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Reconnaissance well at a CO2 storage site near the coal-fired Mountaineer power station in Ohio (USA).

Aerial view of the Edouard LD gas tanker dockingat the Montoir-de-Bretagne methane terminal

in Loire-Atlantique (France).This same type of vessel could be used to transport CO2.

Main optionsfor the capture, transport

and geological storageof CO2.

In plants that emit CO2,carbon dioxide is captured

by separating it outfrom other gases generally

present in flue gas.It is then compressedand either conveyed

by pipeline or shippedto its geological storage site:

deep saline aquifers,depleted oil and gas reservoirs

or unmineable coal seams.

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Head of the CO2injection well

at the Frio experimentalsite in Texas (USA).

the production of coal bed methane (natural gas),which can be recovered and sold.

• storage in basic rocks (basalt, peridotite, etc.) whichat the same time ensures the mineralization ofCO2 through the carbonation of silicates.

Considered for a while, ocean sequestration is oneof the options that has been abandoned becauseof the substantial uncertainties involved in boththe long-term impact of an increased level of CO2on the marine ecosystem and also how long CO2might remain in the ocean.In any case, the technical, financial and societalaspects of CO2 capture and geological storage still need to be dealt with if this new idea is to become a reality and an effective componentof atmospheric greenhouse gas reduction policies.

13

14

At large stationary emission sources Stabilizing man-induced greenhouse gas emissionsin order to avoid upsetting the climatic balancewould, according to IPCC experts, entail retrievingan immense volume of CO2 from the atmosphere,of the order of 3.7 billion tons of CO2 per yearbetween now and 2025, and up to 14.7 billion tonsthereafter. These figures are enormous: to gain a

better idea of their true meaning, this amountproduced yearly corresponds to a volume ofliquefied CO2 that could fill Lake Leman 45 timesover. With our current state of knowledge, theobjective seems too far from reach. Geologicalstorage is only one of the options among a widerange of measures that can be implemented to curbthe increase of atmospheric CO2. However, itscontribution will obviously be all the morepronounced if large volumes of CO2 are stored.At present, only industrial emissions from largestationary sources can be captured. Most of thesecome from power stations - CO2 is released as

Iron and steel production(1) 0.393Cement production(1) 0.308Oil refining(1) 0.188Petrochemical industry(1) 0.142Other industries(2) 0.360Total for industry, exclusive of power plants 1.391Power plants(3) 2.091Total for industrial sources 3.482Annual CO2 emissions in GtC for the main industrial sources (datafor 1994-1996).Sources: (1) IEA GHG, (2) OECD Environmental Data for 1997,(3) IAE World Energy Outlook for 1998.

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Distribution of world CO2emissions by sector More than 60% of CO2 emissionsfrom electricity generation (39%)and industry (22%) areconcentrated and hence moreeasily captured.In the other sectors (39% of the total) emissions are diffuse.

� energy is produced from fossil sources - and fromindustrial production units, notably when certainproducts are manufactured.Transport and energy consumption by residentialand tertiary sectors also generate CO2, but theirassociated emissions are diffuse. These will need tobe reduced by other means, notably through theuse of clean fuels (including hydrogen produced in apollution-free manner) and energy conservation.

At certain industrial sites Power plants today account for 40% of CO2 emissionsthroughout the world, in other words, 7 billion tons ofCO2 per year. Among the types of fossil fuel used, coaland natural gas head the list. Power stations fed withcoal - the fuel with the highest carbon content - arethe ones most concerned by CO2 capture at thesource.The decarbonization of fossil fuels emerges as anecessity when one realises that notably China andIndia, both big coal producers, have every intention ofusing this resource to support their development.Generally speaking, the Earth's coal reserves couldprovide the answer to the problem of the depletion ofoil and gas reserves with which we will be confronted

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Thermal and electricity generating plants, cement plants, refineries,steel mills and other industrial installations are the main sources of CO2emissions in the world, and are accordingly targetedfor the capture and geological storage of CO2.

CO2 emissions in GtC

Capturing CO2 at large stationary sources and transporting it are technologiesalready exploited industrially, but many obstacles will need to be overcome if recovery on a large scale is to become a reality.

Flue gasto be treated

CO2 Other moleculesAdsorbant

Treatedflue gas

Adsorber

15

The use of hydrogenHydrogen is often regarded as the energy carrier of thefuture. This fuel is widely present, but always in com-pound form, notably in water. Hydrogen can, for exam-ple, constitute a good substitute for gasoline in cars,thereby eliminating one of the main sources of green-house gas and pollution.When oxidized,it simply yieldswater vapour. In vehicles equipped with fuel cells, elec-tricity is generated without combustion by means of anelectrochemical reaction between the oxygen in the airand the hydrogen stored in the tank. This electricity

then turns the engine. Theuse of hydrogen and fuelcells, initially developed forspace travel (the Apolloand space shuttle flights)could revolutionize ourway of life. Nonetheless,since hydrogen only occursnaturally as a gas on Earthin minor trace amounts, it

has to be extracted from a primary source. Its environmental benefit is therefore con-tingent upon the source,how it is produced and how it is used.Its production dependsmainly on fossil fuels, today and doubtless for a long time to come.

CO2 capture is already an industrial technology,used today notably to process natural gas.It is commonly called on in the manufacture offertilizers, in the food-processing industry and in theenergy sector (the oil and gas industry).The main problem is generally the low concentrationof CO2 in the flue gas. Depending on which industry is concerned, this concentration can rangebetween a few percent and 20%. Other gases such asoxygen, water vapour or nitrogen also occur in fluegas. It would be out of the question to seek tocompress them all for storage, from the standpoint ofboth energy and storage capacity. Separationmethods are thus required so as to trap CO2preferentially. A large number of industrial captureprocesses exist on the market, each one with its own specific field of application with respectto the nature of the flue gas (composition,temperature and pressure) to be processed.Three main categories are recognized:post-combustion capture, oxy-fuel combustioncapture and pre-combustion capture.

Post-combustion capture

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CO2 capture by absorptionDuring the absorption phase, the CO2 held in the flue gas is separated outusing a solvent. The solvent is then regenerated by an energy input, andthe CO2 is separated from the solvent and sent off for storage. The solvent,with a reduced CO2 content, is then routed back into the absorber.

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Post-combustion capture is designed to extract theCO2 that is diluted in the combustion flue gas. Itcan be integrated into existing facilities withoutdemanding any major modifications.The most common process is CO2 capture bysolvents, generally amines. Other processes areunder consideration involving the calcium cycleand cryogenic separation. The former consists in

Treated flue gas

Abs

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Energy

ExchangerExchanger

CO2rich solvent

CO2-poor solvent

CO2 to storage

Flue gasto be treated

quicklime-based capture that yields limestone;this is then heated, thereby releasing CO2 andproducing quicklime again for recycling.The cryogenic process is based on solidifying CO2by frosting to separate it out.CO2 separation may also be obtained by contactwith an adsorbent solid or through a membrane.before too long. If we could succeed in decreasing or

even eliminating emissions related with this fuelaltogether, it might recover its social status andrespond more readily to global economic andenvironmental challenges.Four industrial sectors could also have recourse to CO2capture and storage: iron and steel production (themanufacture of one ton of steel generates on average1.8 tons of CO2), cement production, the refining of oilproducts and the petrochemical industry.These fouractivity sectors combined release over 3.7 billion tonsof CO2 each year. Lastly, in certain industries likeammonia production and the processing of naturalgas, the techniques involved already entail separatingout CO2.Today, this is released into the atmosphere,whereas it could easily be recovered for storage.

Prototypes of fuel-cell-poweredvehicles: PSA's fire department car,named H2O, and a Renaultprototype.

CO2 capture by adsorptionThe CO2 in the flue gas is adsorbed on a solid that is regenerated either byan energy input or by a drop in pressure. The CO2 obtained uponregeneration is sent off for storage. The regenerated solid is then re-usedfor adsorption.

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Raw coal

Pulverized coal

Pureoxygen

SteamWater

Air CO2

Flue gas condensing

unitDe-dusting

unit

Pulverizer

Coal supply

Flue gasrecirculation

Desulphurizationunit

Smokestack

Air separation unit

Boiler

This technology is not CO2 capture in the true sense ofthe term. Here, the process is applied at the input asopposed to the output stage: the objective is to obtainflue gas with a 90% CO2 content by performingcombustion in the presence of pure oxygen. Because itrecycles part of the CO2 as a substitute for thenitrogen in air, oxy-combustion is particularly wellsuited when an existing facility is being retrofitted.However, separating out the oxygen from air,performed mainly using the cryogenic principle, isboth costly and energy-consuming. To give an idea, theenergy consumption involved in supplying pureoxygen to a 500 MW coal-fired power station thatoperates 8000 hours a year would represent 15% ofthe electricity it generates annually. To avoid the costof separating out the oxygen from air, a promisingtechnology is under consideration: chemical looping

combustion. It consists in bringing the oxygen in theair into contact with a metallic medium that, when itcirculates, transfers the oxygen.

Pre-combustion capture

Capture by oxy-fuelcombustionCombustion in the presenceof oxygen is a technologythat has been successfullyapplied for many years toenhance performance inindustrial processes,particularly in the glassindustry. The combustion offossil or biomass fuels inindustrial boilers in thepresence of oxygen togenerate steam or electricityis one of the majororientations for CO2 emissionreduction.

16

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Oxy-fuel combustion capture

With this type of process, the goal is to trap thecarbon prior to combustion: the fuel is converted onentering the installation into synthesis gas - amixture of carbon monoxide (CO) and hydrogen.The two main techniques are steam reforming* ofnatural gas in the presence of water and partialoxidation* in the presence of oxygen. The CO presentin the mixture reacts with the water during the shift-conversion stage to form CO2 and hydrogen.The CO2 is separated from the hydrogen, which canthen be used to produce energy (electricity or heat)without giving off CO2.

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Progress & prospectsSubstantial research & development efforts are now inprogress aimed at improving capture technologies so as torender them more efficient and more cost-effective.Supported by private international consortia like the “CO2Capture Project” (CCP) or by the European Castor and Encapprojects, the research concerns all technological aspects,ranging from the energy consumption involved in theprocesses (capture currently results in a significant over-con-sumption of energy) to solvent performances (their stability,regeneration potential and selectivity) and including sys-tems to remove trace elements, membrane technologies,designing new catalysts or capturing CO2 as a hydrate.

The search for the best integration of the capture processinto the industrial production plant is a major challenge.Additional power is required to separate and compress theCO2. The amount of energy needed depends on both theintrinsic performance of the CO2 capture system adoptedand an efficient energy management throughout the plant.For example, in the post-combustion process involvingamines, regenerating the solvent currently requires an ener-gy supply of approximately 3 or 4 billion joules per ton ofCO2, mainly in the form of water vapour. Two options existfor supplying the vapour: a boiler used solely for this purposeor the retrieval of vapour from the plant's low-pressurestage. This latter option provides better energy manage-ment, with the challenge of maintaining a high output ofthe production plant.

Costs necessarily depend on the composition of the flue gas,the volume of emissions being processed and the type ofCO2 capture technology used. A general idea can neverthe-less be gained by considering the cost of CO2 post-combus-tion capture by chemical solvents, currently the best devel-oped techniques from an industrial point of view. Economicanalyses, generally carried out in the context of electricitygenerating plants, yield an average capture cost thatincludes CO2 compression, of 30 to 60 euros per ton of CO2for a 500 MW power station, which corresponds to a 50 to70% increase in production costs per kWh.The target is to reduce the capture cost to around 20 to 30 euros per ton of CO2.

Improvingtechniques

Integratingcapture into

industrialprocesses

Reducingcosts

Carbon dioxide might betransported using

the same type of vessel as this LPG tanker.

Cross-section of a vesselequipped with leak-proofreservoirs, for the safetransport of gas.

17

Once separated, the CO2 must be conveyed to its storage site. Various transportmeans are available. However, in view of the volumes required, the only solutions that are practicable on a large scale involve pipelines or shipping.

Shipping Tankers can be used to cover long distances or for offshore storage. Here the gas is pumped into tanks aboard ships having characteristicssimilar to those used to transport liquefiedpetroleum gas. The CO2 is transported in a liquidphase under moderate pressure and at lowtemperature. A certain experience has already beengained in this area: since 1989, HydroGas andChemicals in Norway has been using four tankersto carry CO2 between production sites (ammonia

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plants) and ports where the CO2 is used in foodmanufacture. The firm's four tankers are ofmoderate size. Larger vessels will need to be builtto transport CO2 for storage purposes.

Onshore and offshorepipelinesThe technique involved in transporting CO2 bypipeline does not raise any fundamental problems.This largely inert gas is already conveyed by gaspipeline for use in enhanced oil recovery(approximately 3000 km in the world,essentially in the United States, where the method

has been in use since 1980 to convey 50 milliontons of CO2 annually). During transportation, CO2 ismaintained in a supercritical state under a pressureof more than 74 bars. This type of transport mayentail intermediate recompressions depending on

the distance travelled. The possibility oftransporting CO2 by pipeline in a liquid state, underadequate temperature and pressure conditions,10 bars at -40° C, for instance, is currently beinglooked into. This latter solution would require the

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Sandy formations suitable for CO2 storage lie only a few kilometres offshore,not far from this Kalundborgrefinery in Denmark; transitwould be by pipeline.

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Compressor room for natural gasbelonging to EGG, a subsidiaryof Gaz de France. Prior to

transport, the CO2 must becompressed.

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pipelines to be well insulated.However, a fully fledged pipeline network wouldneed to be built and managed in order to carry theCO2 from its point of emission/capture to thestorage sites.

18

In the United States,the most extensive onshorenetwork has been builtfor transporting CO2from either naturally occurringcarbon dioxide deposits or industrial sources whereemissions are captured.

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Laying down a pipeline for gas transport in Canada.

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Specific constraintsCO2 transport implies specific constraints: the gas must notably be dehydrated to pre-vent corrosion. According to the type of fuel or pollution abatement processes used, dif-ferent kinds of impurities may be present in the gas to be compressed. In the case ofpost-combustion capture, the CO2 may contain nitrogen and sulphur oxides in low con-centrations.In the case of oxy-fuel combustion, oxygen and nitrogen are also present. With pre-combustion capture, hydrogen and natural gas are present in addition to CO2. Otherimpurities, like traces of hydrocarbons or solvents, may further complicate matters.Their potential impact on transportation and surface installations is poorly known forthe moment, for research on the thermodynamics of CO2 in the presence of impuritiesis still in its early stages. The problem of corrosion due to the presence of water canreadily be solved by more thorough purification and dehydration and the use of corro-sion inhibitors.

The cost of transporting CO2by pipeline between its cap-ture point and the storagesite varies between 0.5 and10 euros for conveying oneton of gas over a distance of100 km.This considerable dif-ference depends on thenature of the zones throughwhich the pipelines run. Thecost for an offshore pipeline,for example, is three timesthat of an onshore one.Estimates show that ship-ping could prove economicalover long distances, but thatit would demand high-capac-ity buffer storage facilities.

Carbon dioxide is a colourless, odourless, non-flammable and non-toxic gas, except athigh concentrations. At a concentration of 5%, respiratory difficulties occur, and at 20%it is lethal. In the event of an accident along a pipeline, the CO2 would mix with air andwould only present a threat close to leaks or in depressions where, being heavier thanair, it is liable to accumulate.

The development of CO2 capture and storage techniques does not depend solely onovercoming technological challenges. Other barriers of an environmental or societalnature must also be taken into account. These have been addressed in a number ofstudies, among which we might mention research into legal obligations, and their reg-ulatory framework, or questions of safety or proximity: pipelines running near residen-tial areas, with the possible “NIMBY”* syndrome (Not In My Back Yard).

The problem ofimpurities

The costs

Risksand safety

Regulatoryobstacles

50Transport cost (€/t of CO2)

45

40

35

30

25

15

20

15

10

00 100 200 300 400 500

Length of pipeline (km)

3 Mt/yr. of CO2 (onshore) 10 Mt/yr. of CO2 (onshore) 3 Mt/yr. of CO2 (offshore) 10 Mt/yr. of CO2 (offshore)

CO2 transport costs by pipeline vary depending on network length, flow-rate and location (onshore or offshore).

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Carbon dioxide can be stored in deep aquifers, in oil and gas

reservoirs nearing depletion and even in coal seams.

It is an attractive idea to recycle captured CO2 byconverting it into a different product withcommercial value: fertilizers, construction materials,fuel for vehicles (ethanol, methane), growing algae,the vulcanization of tyres, composite materials,pigments for paints, just to mention a few. But in acontext of combating greenhouse effect, theseindustrial outlets only represent a marginalproportion of captured CO2.Hopes are therefore founded essentially ongeological storage. However, the feasibility of theprojects will have to be demonstrated, because thegeological storage of CO2 has the duty of ensuringthat future generations will only experience zero ornegligible local environmental impacts.Research on ocean sequestration has, to all intentsand purposes, been abandoned today for this veryreason. It seems difficult to prove the long-termharmlessness, for marine fauna and flora, of surplusman-induced CO2, all the more so since theirreversibility of the process cannot be guaranteed.Storing CO2 in disused mines or natural caves is nota good solution either because, although quite

Various possibilities for the geological storage of CO2CO2 may be injected into deep geological layers of porous and permeable rocks, which commonly form saline aquifers, saturated with brine unsuitable for human consumption. The presence ofimpermeable layers (clay, salt, etc.) overlying the storage sites prevents any CO2 from escaping to the surface. Locally, these rocks may host oil or natural gas reservoirs that possess intrinsic trappingstructures: CO2 storage is possible in depleted or declining reservoirs, with the potential for implementing enhanced oil recovery. Lastly, CO2 storage is possible in deep unmineable coal seams,where CO2's affinity for coal enables methane to be produced.

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Recovery, or EOR*, designed to enhance theproductivity of oil fields;

• storage in deep unmineable coal seams, whichtakes advantage of CO2's affinity for coal; it isbased on one of the so-called Enhanced CoalBed Methane, or ECBM* recovery methods usedto exploit natural gas trapped in thesestructures.

To ensure the storage facility is leak-tight, animpermeable layer composed of clay or salt must

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accessible, their volume is too limited and the risksof leakage into the atmosphere too high.On the other hand, the CO2 injected into deepgeological layers can fill the inter-granular spaces ofthe porous and permeable rocks that composethem. In reservoir rocks, the storage potential isenormous: these are located in sedimentary basinsfound the world over and may in places extend overhundreds or even thousands of square kilometreswith a thickness of several kilometres. In most cases,the pores are occupied by brine, which is totallyunsuitable for human consumption. This is why theterm “saline aquifers” is used. Locally, these reservoirrocks can contain oil or natural gas fields.Large quantities of CO2 can also be captured byadsorption* on coal, as it displays a great affinity forCO2 molecules.Three types of geological storage can thus beenvisaged:

• storage in deep saline aquifers that offer thegreatest storage capacity;

• storage in depleted or declining oil and naturalgas reservoirs; this is merely an adaptation of aprocess already widely experimented in the oilindustry, commonly termed Enhanced Oil

overlie the reservoir rock, to prevent any CO2 frommigrating towards the surface.

At depths beyond 800 mCarbon dioxide must be injected at a depth that issufficient to attain pressure and temperatureconditions that will maintain it in a supercritical state(more than 31° C and at a pressure of 74 bars). In thisstate, CO2 is denser and occupies a smaller volume.The depth necessary to reach this supercritical state,depending on the local geothermal gradient, variesbetween 700 and 900 m.CO2 stored underground in a supercritical statecan dissolve in pore water and trigger geochemicalreactions with the minerals in the rocks. Theseprocesses, although slow, result in CO2 beingtrapped in a dissolved form, or even a mineral formif conditions favour the formation of carbonateminerals. This increases the storage potential ofthe formation and may even retain the CO2permanently.

For how long must CO2 be stored?Once captured, the CO2 must be stored over long periods of time, corresponding to at leastthe interval during which the CO2 emission problem is likely to remain critical. Naturalprocesses must likewise be respected. The carbon cycle is governed by exchanges betweenthe atmosphere and the ocean, on the one hand, and the biosphere and the atmosphere, onthe other. Biosphere exchanges vary on a scale of decades, but the oceanic cycle lasts sever-al centuries. In order to stabilize CO2 content in the atmosphere, the CO2 must be retainedunderground for periods compatible with the oceanic cycle. As a precautionary measure,solutions are being considered that will allow storage to be prolonged over periods of up tothousands of years. It is reasonable to believe, however, that retention beyond the era ofmassive fossil fuel use, i.e. at least several centuries, will suffice.

Map of porositydistribution at cm-scaleand the correspondingsandstone thin section.On the left-hand photo, porosity isshown in blue.

SEM image (x 54) of a reservoirsandstone: note the interstices

where water, oil or gas cancirculate.

The different types of storageCO2 Capacity

(in Gt) Advantages Disadvantages

Hydrocarbonreservoirs 930 Gt

Trapping structures impermeable to non-reactive gases. Well-known structures.Economic potential through EOR.

Generally far from CO2emission sites. Storagecapacities often limited.

Deep salineaquifers

400to 10,000 Gt

Widespread geographic distribution andvast storage potential. Facilitates the searchfor storage sites close to the sources of CO2emissions.Water unfit for drinking.

Poorly characterized to date.

Unmineable coal seams 40 Gt Near CO2 emission sites. Economic

potential through methane recovery.

Injection problems due to thepoor permeability of coal. Limitedstorage capacities.

A petrifying spring near Digne in the Hautes-Alpes: the waterladen with dissolved carbonatesdeposits them as travertine(foreground).

New Mexico and Mississippi, with sometimes up toa billion tons of CO2!), in Australia (South Australia),in China and, to a lesser extent, in Hungary, Italy,Germany and Greece, for example. In France, eightnatural reservoirs have been identified in thesoutheast basin, which were discovered during oilexploration in the sixties and seventies. They containCO2 in a virtually pure state (up to 99%), like atMontmiral, in the Drôme Département. Thesenatural deposits may serve as analogue models forunderstanding the long-term behaviour of CO2 inthe subsurface.These deposits therefore attract interest from the

22

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Carbon dioxide storage is a field that alreadybenefits from significant technological and scientificadvances, but a leap in scale must still be made to guarantee storage safety over extensive areas and in the long term.

Nature's modelThe geological storage of CO2 is not one of man'sinventions. Many natural CO2 fields have existed inthe subsurface for thousands or even millions ofyears in certain sedimentary basins. The largest ofthese are located in the United States (Colorado,

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The French carbon dioxideprovince: several naturalcarbon dioxide reservoirsexist in France (stars) andmany springs of carbonatedwater (red dots) are tapped for cures or marketed as bottled water.

Head of the carbon-dioxideproduction well at Montmiral

in the Drôme: this naturaldeposit of 97% pure CO2is being studied in detail,

with fluid sampling, chemicaland isotopic analyses

(wells and springs) andmineralogical analyses.

The Bard Roman fountainat Bourdes in the

Puy-de-Dôme: the holeis some 60 cm deep,

and bubbling can be seenon the water surfacedue to the presence

of CO2 gas .

international scientific community. In Europe, theNascent research project conducted between 2001and 2004 and in which BRGM participated on behalfof France, aimed to study the largest Europeandeposits, including that of Montmiral. A great deal ofinformation was gained about the physical andchemical interactions between the reservoir rocksand the fluids (CO2, water, oil and gas). It yielded veryimportant data for assessing the efficiency of storageprocesses over the long term.©

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Oil industry experienceNatural CO2 fields have been exploited for a numberof decades by the oil industry, which has actuallygained a significant amount of experience inmanipulating and transporting CO2 and in injectingit in the subsurface. Carbon dioxide is used toenhance the recovery of hydrocarbons. Thetechniques implemented since the early 1950's havemade it possible to double the retrieval rate for oilcontained in the deposits: the injected CO2maintains the reservoir's pressure and, by dissolvingin the oil, decreases this latter's viscosity andfacilitates its migration towards the production well.Thanks to progress made in recent years, between 30and 60% of the original reservoir can now berecovered. The term adopted for this technique is“Enhanced Oil Recovery,” or EOR*.Part of the CO2 systematically migrates upward tothe surface in a mixture of oil, water and gas. Oncethe oil has been refined and separated, the CO2 canbe retrieved then re-injected, thereby avoiding itsescape into the atmosphere. The recycling optionalso makes it possible, partially at least, to overcomeproblems related to supply and fluctuations in CO2

Recycled CO2 and water

CO2 Water Oil

Injectedwater

Mixing zone Oilreservoir

Additionaloil recovered

Oil recovered

prices. Recycling should increase in the context ofcombating greenhouse effect: more systematicrecourse to CO2 injection as an enhanced recoverytechnique could result in increased CO2 purchasesfrom industrial sources. At present, the CO2 it uses isessentially derived from natural deposits (the leastexpensive), and only 1/5 comes from industrialcapture.

Experience in natural gas storage The oil and gas sector has long been carrying out gasstorage operations in the framework of managing itsproduction line. These limited and short-termoperations, with seasonal cycles, are also notunrelated to geological storage. The sites are

� The principle of Enhanced Oil Recovery (EOR),which improves the production of hydrocarbon reservoirs nearing depletion.

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Gaz de France Production Nederlands (GPN) platform in the North Sea,where an operation of CO2 storage in a natural gas reservoir nearing depletion is under consideration.

France has fourteennatural gas storage sites

in reservoirs at depthsranging between 400 and

1600 m, mainly withinlayers of water-saturated

rock, i.e. aquifers.

primarily former oil and gas reservoirs that are nolonger productive, but also, to a lesser degree, simplyaquifers. In France, this latter solution is the mostcommon. More than 500 gas storage sites areoperational throughout the world, representing avolume of 164 billion cubic metres.

Pioneering experienceSince the early 1990's, several projects have beenundertaken in order to examine the feasibility ofgeological storage. The first operation, launched in1996, involved the injection into a deep aquifer ofone million tons of CO2 per year at the NorwegianSleipner site in the North Sea. This was the firstindustrial operation of CO2 geological storage to beconducted with the environmental objective ofcombating greenhouse effect.

Aquifer storage site, in operation(département – start-up date)

Storage site in saline cavities, in operation (département – start-up date)

Future storage site in saline cavities

Pipeline

Future storage site in a depleted reservoir

St-Clair-sur-Epte (95) -1979 Gournay-sur-Aronde (60) - 1976

Germigny-sous-Coulombs (77) - 1982

Trois-Fontaines (51) Cerville (54) - 1970

Alsace-Sud (68)

Etrez (01) - 1980

Tersanne (26) - 1970

Hauterives (26)

Manosque (04) - 1993

Izaute (Total)

Lussagnet (Total)

St-Illiers-la-Ville (78) -1965

Beynes supérieur (78) -1956Beynes profond (78) -1975

Céré-la-Ronde (37) -1993

Chémery (41) - 1968

Soings-en-Sologne (41) - 1981

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Deep saline aquifers are regarded as the mostimportant geological reservoirs for storing CO2.In Norway since 1996, one million tons of CO2 arebeing stored per year in a sandy aquifer beneath the North Sea.

A huge potential Aquifers, commonly associated with sedimentarybasins, consist of porous or permeable water-saturated rocks. The substantial storage capacitiesknown to exist and the wide geographical extentcovered by these basins favour a shortening of thedistance between the CO2 source and the storagesite. For all these reasons, CO2 storage in aquifersheads the list of the geological options currentlyunder consideration, the storage capacities being,according to some estimates, ten times greater

24

Injection into geological layers beneath the North Sea Many projects for storing CO2 in deep aquifers arebeing examined, such as that of the firm Statoil inthe Barents Sea, in partnership with Gaz de Franceand Total, on the natural gas production site ofSnøhvit. This is also the case for Sleipner, a naturalgas pool located about 200 km offshore in themiddle of the North Sea and exploited since 1996by Statoil. This gas consists essentially of methane,but also contains from 4 to 10% of CO2. To complywith sales criteria, the natural gas must beprocessed to bring its CO2 content down to 2.5%.This operation is performed offshore. The naturalgas that is produced is sent on to a differentplatform to extract the CO2 (the process involvingabsorption by amines). This latter is then injecteddirectly into the largest local saline aquifer, almost1000 m beneath the ocean floor, in the Utsira sandformation. Each year, a million tons of CO2 areburied in the marine subsurface instead of beingreleased into the atmosphere, as is generally thecase. The operation is financially viable, since theinjection costs are offset by the existence inNorway of a tax on offshore CO2 emissions.

The Norwegian Sleipner platformin the North Sea

producing natural gasand separating out CO2,

which is re-injectedinto a saline aquifer.

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CO2 re-injection in the Barents Sea in the vicinityof the Snøhvit natural gas reservoir.

Map of the major sedimentary basins and hydrocarbon field zones.Deep saline aquifers in sedimentary basins and oil and gas pools either depleted or nearing depletion are potential candidates for the geological storage of CO2.

than those of oil or gas reservoirs. For Europe, theyprobably represent more than 800 billion tons ofCO2, and worldwide some 10 trillion tons of CO2(i.e. enough to store all the world's emissions forcenturies to come!). The cost of undergroundstorage has been estimated at 2 to 3 euros per ton,although offshore aquifer storage remains costly(around 25 euros per ton).

• predictive modelling of how CO2 evolves in thereservoir with time;

• an estimation of the monitoring requirementsand the associated costs.

A manual of good practice based on the results of this pilot project was drafted for use as a guidein all future geological storage operationsthroughout the world.

A follow-up to the SACS project, CO2Store (2003-2006), is intended to study the long-termbehaviour of the CO2 injected at Sleipner and to examine the feasibility of storage in an aquifer at four other sites in Europe, twoonshore (Wales and Germany) and two offshore(Denmark and Norway).

The world's first site of CO2 storage in a deep salineaquifer, the Norwegian Sleipnersite in the North Sea.The natural gas is tapped at a depth of 2500 m beneath the drilling platform before CO2separation on the gas-processingplatform. The CO2 is then injectedinto the sandy Utsira aquifer ata depth of 1,000 m.

The Sleipner platform by night.

The Sleipner gas reservoirlies some 200 km offshore

in the middleof the North Sea. 25

The SACS projectThe European research project entitled SalineAquifer CO2 Storage (SACS) was launched in 1998in order to study geological storage at the NorthSea Sleipner site. Funded by the European Unionand industry, with the participation of researchinstitutes including BRGM and IFP, it has allowedinformation to be compiled in several areas:• the detailed geological description of the

reservoir: this activity is fundamental for theproject, since it makes it possible to ensure thatstorage in the geological structure in question isfeasible and devoid of danger;

• a study of the geochemical aspects, so as toassess the interactions between the CO2injected and the host rock;

• monitoring the operation: it proved possible totrace the evolution of the CO2 bubble through theinterpretation of repeated 3D seismic campaigns;

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A work station for seismic interpretation: many techniques andmethodologies are used to monitor and predict the long-term evolution ofCO2 storage sites, including geophysics, seen above.

A 3D model for monitoring CO2 storagein the aquifer after three years of injection

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Since September 2000, an operation of enhanced oilrecovery by CO2 injection has been conducted byEnCana at the Weyburn oil field in Saskatchewan,Canada. In January 2001, an international researchprogramme was launched under the aegis of theInternational Energy Agency (IEA) and called the IEAWeyburn CO2 Monitoring and Storage Project. Its goalwas to take advantage of this industrial operation tostudy the potential of CO2 geological storage in an oilreservoir and to consider how best to combine oilrecovery and long-term storage.The CO2 comes from a coal gasification unit in NorthDakota, USA. It is transported to Weyburn via a 330 km-long, cross-border pipeline designed especially

26

Oil and gas reservoirs are by definition trappingstructures, hence the idea of storing CO2 indepleted pools. The storage of CO2 in thesereservoirs can offer an extra advantage, thatof enhanced oil and gas recovery.Research programmes are underway to study the long-term behaviour of the CO2 injected into this type of formation.

A mine of dataAfter a century of intensive exploitation,thousands of oil and natural gas pools are nearingdepletion, and certain of these could representinteresting geological storage sites.The global storage capacity in hydrocarbonreservoirs corresponds to some one trillion tons of CO2. Although this is ten times less thanthat of aquifers, it nevertheless represents the equivalent of a third of a century's worth ofthe world's emissions.The choice of oil reservoirs offers quite a fewadvantages:• low-cost exploration, since the geology is

already well known;• proof that the reservoirs have been capable of

retaining liquids and gases over millions ofyears;

• sites already equipped with production andoften injection facilities, which could be used totransport and inject the CO2;

• enhanced recovery of the remaining oil andnatural gas reserves in the pools;

• regulations already in existence.Unfortunately, the disadvantages of this type of reservoir include their uneven geographical distribution throughout the world,their limited storage capacity compared to saline aquifers and the need to control the existingwells to avoid preferential migration of CO2towards the surface. Depending on local,geographical and economic contexts, they can still be of interest.

Weyburn, a pilot site combining CO2 storage and enhanced oil recovery

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� The CO2 injected into the Weyburn oil reservoir in Canada comes from the coal gasification unit at Beulah, North Dakota (USA):5000 tons of CO2 transit each day via a 330 km-long cross-border pipeline.

Geological settingof the CO2 storage site

as defined by a block200 x 200 km lying at a depth

of between 1.5 and 4 km.The monitoring zone extends

10 km beyond the limitsof the CO2 storage area.

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in Canada.

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Graph showing the increase in oil production related to CO2 injection since the end of 2000.

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Overall view of the Beulah coalgasification industrial complex in North Dakota, USA,operated by the DakotaGasification Company (DGC).

Before being fed into the pipeline,the CO2 passes through the Beulahplant's compression unit.

for the purpose.The objective is to inject 1.8 milliontons of CO2 a year for fifteen years, thereby enabling 20million tons of CO2 to be stored permanently while atthe same time producing 130 million additional barrelsof oil.The European Union is participating in thefunding of the Weyburn research project.The Europeancountries involved are Denmark, France (BRGM), Italyand the UK, in collaboration with Canadian andAmerican research teams.The project's first phase (2001-2004) has alreadyprovided several results:

• the detailed characterization of the site, startingwith the reservoir at a depth of 1400 m up to thesurface, at both local and regional scales;

• the development of methods for predicting andmonitoring CO2 migration;

• the technical-economic modelling of the reservoir:optimization of oil production and CO2 storage,calibration using production data;

• the development of methodologies for evaluatingstorage performance and associated risks.

The CO2 re-injection pilotin a natural gas field in the North Sea

Exploited since 1987 in the Dutch NorthSea, the K12B gas field is now runningdry. The CO2 extracted from the naturalgas is released into the atmosphere. Gazde France, in a joint undertaking withthe Netherlands (the Offshore Re-injec-tion of CO2 project - ORC), has installed apilot to re-inject the last tons of CO2extracted into the pool: an environmen-tal measure, but also an opportunity totest the storage capacity of this reser-voir, which might subsequently receivethe CO2 extracted at other platforms.The injection potential has been calcu-lated to be 480,000 tons/yr. of CO2, at acost of 8 euros per ton.

3D model of K12B: tapped since 1987, this natural gasreservoir nearing depletion is known in detail andrepresents an ideal target structure for completely leak-proof CO2 storage.

Investigations will be pursued with the Weyburn IIproject.The stakes are high: the experience gained in this areawill be a determining factor for the future of geologicalstorage in hydrocarbon reservoirs.

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Of all fossil resources, coal is the one representingthe greatest potential. Although a large proportion of it is easily extractable, huge reservesremain that will never be mined because they are inaccessible. CO2 storage in unmineable coalseams can allow methane to be retrieved in the process. Research programmes have been undertaken to examine the feasibility of this option.

An affinity for CO2Despite some handicaps intrinsic to coal, inparticular its relatively poor permeability, whichlimits its potential for injection at a high flow rate, other factors are in favour of CO2 storage in coal seams.Their adsorption* capacity first and foremost:coal has the unusual feature of commonlycontaining large amounts of gas trapped withinits internal structure. This is generally methanegas, the cause of firedamp explosions. Coal,however, has an even greater affinity for CO2insofar as it can absorb twice as much as it canmethane, hence the idea of storing CO2 in coalwhilst at the same time retrieving the methanegiven off in the process.Secondly, their location: coal seams are relativelycommon and widely present throughout thecontinents. They are also to be found nearindustrial facilities or power plants that areimportant CO2 sources, thereby reducing transport costs.The last advantage is that this option is economic:the methane can be recovered and sold. The

The principle ofEnhanced Coal Bed Methane

(ECBM) recovery,which allows

the natural methanegas trapped in coal

to be tapped.

Detail of the dsorption/desorptionmechanism inside beds in the coalseam: during adsorption, carbondioxide bonds with coal, whilemethane is desorbed; the ratiobetween the adsorption of CO2and the desorption of methane(CH4) is 2:1.

28

The main obstacle lies in the permeability of coal,which is not always sufficient to ensure that CO2can be readily injected. The adsorption*/desorptionmechanisms of CO2 and methane in the pores of coal also need to be better understood.Experiments are being conducted in the laboratoryand on-site with the aim of making progress in these areas.An alternative would consist in injecting CO2into sedimentary aquifer zones interbedded withcoal seams and to take advantage of theadsorption* capacities of coal as a CO2 filter,a large-scale activated carbon filter as it were.In this case, the CO2 would be stored primarily inthe aquifers, with the coal seams forming adynamic cover due to their affinity for CO2.

The American Coal-Seq projectThe Coal-Seq project was launched in the UnitedStates in October 2000. Funded by theDepartment of Energy (DOE), this project studiescoal seams in the San Juan Basin, on the Colorado-New Mexico border, the largest methane-producing basin in the world. On one of the sites(Unit Allison), CO2 was injected for five years. Themethane release was in agreement with reservoirmodelling predictions, with a very low CO2 contentin the final gas. A comparison was made withanother site (Unit Tiffany), where nitrogen wasinjected. Here, although methane production wasgreater, nitrogen increases rapidly in the methanerecovered, meaning that the gas produced mustbe processed, which turns out to be costly. TheCoal-Seq project has demonstrated the economicadvantages of CO2 injection for methane recovery.

H2O

CH4CO2CO2

injectionReduce methane partial pressure

in cleatsH2O + CH4

by transportto wells

Methane desorbed from and carbon dioxideadsorbed into coal matrix

CO2

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Extraction and purificationof methane

Power stationalso producing CO2

Injection ofthe captured CO2

Coal seam

methane in coal seams represents a vast energyresource that is rarely exploited today, but whichcould become more widely used in the future in conjunction with an enhanced recovery processbased on CO2 injection (Enhanced Coal BedMethane recovery, ECBM*).The potential for CO2 storage in coal seams,although difficult to assess accurately, representssome 40 billion tons of CO2. Only unmineableformations are concerned, because sites wherecoal has already been mined are riddled withgalleries and shafts that would serve as quickescape routes for CO2 migration to the surface.International research projects have been set up in recent years to confirm the feasibility of large-scale CO2 storage in coal seamsaccompanied by methane recovery.

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The Coal-Seq project: sixteen methane-producing wells (photo),four CO2 injection wells and one observational borehole are in operation at the Allison site in the San Juan Basin, New Mexico (USA).CO2 injection over a five-year period has enabled the production of methane with a very low level of carbon dioxide.

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The Canadian ECBM* projectLaunched in 1997, this Enhanced Coal Bed Methanerecovery project involves many national andinternational players. Its purpose is to study CO2re-injection in the Alberta coal mines, in theFenn/Big Valley area. Several injection tests wereperformed with various CO2 and nitrogencombinations. These tests resulted in a databasethat enabled the numerical model to be validated.The operation demonstrated the actual feasibility ofCO2 storage in coal-bearing structures.

The European Recopol projectThe Recopol project, launched by the European Union in November 2001, aims to reduce CO2 emissionsthrough CO2 storage in a coal basin in Poland.To implement this project, an international consortiumwas set up, composed of research institutes, universitiesand European oil and gas companies. France isrepresented by IFP, Gaz de France, Air Liquide andGazonor.The site selected is the Silesian Basin, wheretwo methane-producing wells have already been inoperation since 1996.The CO2 provided by Air Liquide is

conveyed by tanker trucks.The European project targetsthe same objectives as the American and Canadianprojects: assessing the feasibility of CO2 injection intocoal seams. It also calls upon modelling and laboratoryexperiments, which could act as a reference basis and adecision-support tool for the concerned industrialplayers.The flow rate of the injected CO2, initially 1 to 3 tons ofCO2 per day, was increased to 12 to 15 tons of CO2 perday as of April 2005, which has made it possible to studythe injection capacity in coal seams.The associatedmethane production is currently being evaluated.

One of the four CO2-injection wells at the Allison site,part of the Coal-Seq project.

Operational pilot in Polandfor the European Recopol project:

halfway between the twomethane production wells,a well injects CO2 at a rate

of some fifteen tons per day.The objective is to assess

the capacity for CO2injection into coal seams

and the associated increasein methane production.

Core sampling taken for a detailed study of the rocks intersected when boring a well for CO2 injection into the coal seam.Prior to injection,the CO2 transported by truck is stored atthe surface in tanks (lower photo).

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Although it has not as yet achieved the same levelof technological advancement as geological storage,the conversion of CO2 into carbonate rock is a line of research that is beginning to be explored.

An emerging conceptThe notion of transforming CO2 into a stable substancehas been around for about ten years. It is based onobservations of the formation process of carbonaterocks in nature, dating back millions of years.These rockscome into being through a whole series of variedinteractions (surficial weathering, groundwatercirculation and hydrothermal activity) between a water-based fluid and fragments of silicate rocks enriched incalcium and magnesium.The calcium and magnesiumsubsequently react in the presence of CO2 to precipitateas carbonates.These reactions, well known to geologists,can be reproduced artificially.Two axes are currently being explored: mineralsequestration ex-situ, which involves industrialprocessing, and in-situ mineral sequestration. In thislatter case, the injection takes place in a naturalsetting where the chemical conditions are highlyfavourable to the mineral sequestration of CO2(a reservoir in basic rocks of magmatic origin, such asbasalt); the IPGP (Institut de Physique du Globe deParis - Paris Geophysical Institute) and BRGM havebegun to pursue this line of investigation.

The search for industrial processes Several ex-situ mineralogical sequestrationexperiments have already been carried out. A typical

operation consists in introducing a concentrated CO2source into a reactor, where crushed olivine orserpentine (magnesium-rich silicate rocks) from amine have already been placed.When heated to ahigh temperature, the reaction yields carbonate rockplus some residual CO2, which can then be recycled.There are two advantages to this concept: long-termstability of the trapped CO2 and huge storagecapacities, as the raw material (the magnesium-richsilicates) is plentiful on every continent. However, theprocess is still relatively slow, and most of thereactions require both high pressures and hightemperatures, which drives up the cost. Lastly, a large-scale development of the method would not bedevoid of environmental repercussions. It is estimated

30

that a 500-MW power plant generating approximately7200 tons of CO2 per day would need a little over20,000 tons of ore per day to trap the CO2 in mineralform.The resulting carbonates would either bereturned to the mine or put to a variety of uses,including landfill.Another approach could be to have the CO2 react, notwith natural rocks, but with solid or liquid industrialwaste. Fly ash, for instance, which is waste from coal-fired power stations, is composed of iron oxides,calcium and other metals that can form carbonates.In addition to capturing CO2, carbonation can alsoimmobilize certain toxic heavy metals, which mightmigrate outside the waste-storage zones due toleaching by rainwater.

A study of carbonation of blast-furnace slagThe steel sector in Europe has committed tostringently reducing the carbon content of itsemissions in the framework of the European Ultra LowCO2 Steelmaking project (Ulcos). As part of the 6th

Framework Research and Development Programme,this project involves all European steelmakers (Arcelor,TKS, Corus...), but also research institutes anduniversities (BRGM, CNRS, Cired...) as well as industrialplayers such as EDF. By five years from now, the project is intended to come up with a productionstream that reduces emissions by between 30 and70%, starting from iron ore, with verification of its technical feasibility and predictions concerning its economics and social acceptability.This is indeed an ambitious objective, considering that steelmanufacture generates about 1.8 tons of CO2 perton of steel produced. In order to reduce emissionssubstantially, new processes based on breakthroughtechnology must be tested: one of these relies onthe carbonation of fly ash residues rich in calciumsilicates. The potential for the geological storage ofCO2 in the vicinity of steel mills is likewise beingexamined.

�Samples of blast-furnace slag:mineral combustion residues

are capable of capturingCO2 (carbonation).

Taking advantage of thisproperty could generate a 70%

reduction in CO2 emissionsinvolved in steel production.

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�This highly magnified imageof slag reveals the presence

of a larnite-type mineralpossessing phases that could

form carbonates (red arrows).

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A test rig for mineral carbonationcomprised of two 4-litre autoclavesoperating at up to 200 bars and340° C and fed by a system thatinjects supercritical CO2.

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important to watch out for possible leaks, theoccurrence of geochemical reactions involving thedissolution or precipitation of minerals (whichmay, according to circumstances, have a positive ornegative impact on storage), water quality in theaquifers interbedded between the storage zoneand the surface, and the quality of the overlyingcap rock. These sensitive points must be controlledand monitored by reliable permanentmeasurement systems (geophysical and/orgeochemical).To achieve a complete environmental assessment,it will also be necessary to supervise injection andwhat happens to impurities that may be presentin the CO2. The capture, purification and

31

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Monitoring gas in soil:a probe installed 2 m below the surface is used to measure gasconcentrations in soil.

An experimental rig for controlled pressurized CO2 percolation.The first cell prepares the pressurized CO2 injection solution,

the second receives a core sample of porous reservoir rockat confining pressure, and the third serves

as a pressurized sampling cell.

Repeated 3D seismic imaging to monitor the evolutionof the CO2 bubble at the Sleipner site: in 1994 before injection;

in 1999 after the injection (which began in 1996) of 2.35 million tons (Mt) of stored CO2; and in 2001 when storage reached 4.36 Mt.

Monitoring the geological storage of CO2 calls on awide assortment of techniques and methodologies,the objective of which is to ensure the safety of the technological approach over several centuries.

Multi-faceted monitoringTechnologies currently available in the oil and gasindustry allow CO2 to be captured and storedunderground, but the quest for storing thesubstance without risk to the environment overlong intervals - several hundreds or even severalthousands of years - imposes new restrictions asto the temporal and spatial scope to be covered bythe monitoring. Control measurements will differaccording to whether the phase of the operation isthat of site qualification, injection (from severalyears to several decades) or storage monitoring.If indeed, initially, it is necessary to controlinjection and to locate the “CO2 bubble”, it is also ©

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compression processes do eliminate mostcompounds associated with the CO2, but there canstill be others derived from the flue gas, such assulphur dioxide or nitrogen oxides, that must bespecifically tracked. It is important to know whatamounts are injected and to check that they donot pollute the groundwater aquifers in thevicinity of the storage site.

The contribution of numerical modellingThe information accumulated on the nature of thereservoir can be used in numerical modelling,which can enable long-term predictions about theevolution of the CO2, the simulation of scenariosand the quantification of potential risks such asleakage through the cap rock or the rupture of awell. Several types of models are called on.Engineering models of the reservoir in 3D used togain knowledge about hydrocarbon deposits

32

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Chemical reaction simulations forCO2 injection at Sleipner after atime lapse of 10,000 years.Injected CO2 dissolves in the aquifer,represented by a 200 m-thick layercomposed of minerals liable to reactwith CO2. Initially, calcite (red)accounts for 3.9% of the rockvolume; 10,000 years later,simulations predict that only 0.3% of the calcite has beendissolved by the CO2.

Examples of carbon dioxide leakage scenarios in a geological storagefacility sited in a hydrocarbon reservoir beneath the North Sea, part of theEuropean NGCAS project.

Hydrodynamic modelling at a regional scale (50 km long x 36 km wide x 5 km thick).

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Modelling methodologyis carried out at various scales:

basin, field, and reservoir.

Modelling the vertical migration of CO2 according to a leakage scenario: after 100, 500 and 1000 years.

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provide a description of fluid flow and ofexchanges between water, gas and oil. They can beused in conjunction with geomechanical models,which contribute data on the mechanicalbehaviour of the porous media and of the cap rock.As to geochemical models, these take into accountthe chemical interactions between watercontaining dissolved CO2 and minerals. Lastly,models of the sedimentary basin are capable ofsimulating a reservoir or a storage site within its

geological setting and on a regional scale.For these models to be pertinent and usable,they must be regularly updated with new data,seismic among others, which make it possible to monitor the reservoir's geomechanical evolutionover time and to map CO2 movements.

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34

Starting in 2000, momentum has been developing on the international scene in support of CO2 capture and storage.Research programmes and industrial pilot projects are proliferating the world over…

Although there is no longer any doubt that CO2capture and storage has a very significantpotential for reducing carbon emissions, theconcept, before it can become reality, mustovercome many obstacles, one of the mostdaunting of which is economic. Technologies forconveying CO2 by pipeline and injecting itat depth into geological layers are now operationalat a reasonable cost. On the other hand, theexisting capture techniques remain relativelyexpensive. The cost of the complete technologicalline is currently estimated at 50 euros on averageper ton of avoided CO2 (cf. graph), 85% of which isdue to capture alone (including the cost of

Capture Current cost

Future cost

Cost (€/t)0 20 30 50 70101020 40 60 80

Transport and storage

Value from enhanced recovery

TotalCost of avoided CO2: 60 €/t

Cost of avoided CO2: 15 €/t

a

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b'

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b

c

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(a')+(b')-(c')

In the framework of the European Geological Storage ofCO2 project (Gestco) designed to assess the potential forgeological storage in Europe, decision-support tools havebeen provided to evaluate financial risks.The economicmodelling of CO2 capture, transport and storage isperformed by a group of European scientists in theframework of the Gestco Decision Support System (DSS),in which BRGM is taking part on behalf of France.Information on the subject is collected into a commondatabase and processed with appropriate software.Thus,thanks to this tool, an operator will in future be able toselect a source of CO2 and determine where to store itand how much this will cost.The tool has been designed

Avoided CO2CO2 capture requires the use of

additional energy, which in turngenerates carbon dioxide. Avoided

carbon dioxide emissions areaccordingly calculated by computing

the difference between a powerstation without capture, and one

with capture -but which consumesmore energy. Because of this

mechanism, the amount of capturedCO2 is always greater than

that of avoided CO2.

Reducing costsAt present, even when CO2is used for enhanced oil recovery,the cost of capture, transportand storage adds up to approximately 60 euros per ton.The goal would be to reduce this amount by a factor of 4.

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�separating out the CO2 and compressing it).To be economically viable, this amount should be divided by a factor of between 2 and 4.It is hoped to hopefully, this challenge can beovercome through the development of moresuitable techniques and the standardization of the methods used. A similar action in the pastresulted in a very considerable drop in the price of oil exploitation.

35

Research & Development needsResearch & Development work is necessary to devisenew techniques that are more economical and morereliable for CO2 capture and storage. R&D is particularlyessential for gaining an understanding of the chemicaland physical processes at work in the geologicalstructures intended to host the CO2. Methodologiesmust also be developed for selecting storage sites andpredicting the long-term impact of the CO2 on thereservoir and on the environment, for risk assessment orfor monitoring and verification. Many research projectsin the world are addressing these needs.

The Castor projectThe Castor project (CO2 from Capture to STORage),coordinated by the French Petroleum Institute (IFP),involves eleven European nations and brings togetherthirty public and private partners from the industryand research sectors. It was launched in February

2004 and is expected to conclude in 2008. Its budgetis 15.8 million euros, including an 8.5 millioncontribution from the European Union. Castor has twomain objectives: the first is to cut the cost of post-combustion capture in half, from 40-60 euros per ton

of captured CO2 down to 20-30 euros.To accomplishthis, the project partners are undertaking work aimedat developing, testing and optimizing new processes.A large-scale capture pilot capable of processing 1 tonof CO2 per hour is to be installed in a Danish coal-firedpower plant.The second deals with the geologicalstorage of CO2 and the validation of this concept inEurope from a study of four specific sites:

• A disused oil reservoir in the Mediterranean (theCasablanca field operated by Repsol in Spain).

• A deep saline aquifer in the North Sea (on theSnøhvit site operated by Statoil, with Gaz deFrance involvement).

• Two depleted gas reservoirs: that of K12B in theDutch North Sea, operated by Gaz de France, andthat of Atzbach-Schwanenstadt in Austria,operated by Rohoel.

The European network of excellence, CO2GeoNetCO2GeoNet, the European network of excellence

devoted to the geological storageof CO2, aims to strengthen theintegration and coordination of13 European research institutions

with internationally recognizedlevels of expertise: BGS (the coordinator,

Great Britain), BGR (Germany),

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to calculate the best route for transporting the gasbased on the distance, but also on the pipeline systemsavailable and the geographical setting (topography,built-up areas, watercourses, etc.).Theoretically, this toolwould also make it possible to compute the cost of theseparation and compression of the gas, and that of itstransport and injection. Lastly, cash flow could beestimated on a simple spreadsheet integrated into theprogramme.The cost analysis using DSS indicators is based on thecost of capture according to the post-combustion(amine scrubbing) and pre-combustion methods.

Precise cost estimates have been calculated for 350 European power plants and over 340 industrialplants. In those powered by fossil fuels, this depends ona large number of parameters, among which the mostimportant are the type of installation, increasedinvestment and a drop in production output (between 6and 12 points). In most instances, electricity generatingcosts could be expected to increase from 30-45 eurosMWh to 40-60 euros per MWh, without counting thetransportation and storage of the CO2. Attempts havealso been made to estimate the total cost of the entirechain, with 17 European facilities examined to date.

�In the Castor project, the disusedCasablanca oil reservoir in theMediterranean, 43 km off the

Spanish coast near Tarragon, isbeing considered in the context ofCO2 storage in depleted oil fields.

The running total of the amountof carbon dioxide stored at

Sleipner (1 Mt/yr.), Weyburn (1.8 Mt/yr.) and In Salah (1 Mt/yr.) is some 20 million tons. By addingthe scheduled storage facilities at Snøhvit (0.75 Mt/yr., mid 2006)and Gorgon (4 to 5 Mt/yr.,end 2006), the total amounts to 50 Mt by 2009 and 100 Mt by 2014,and certainly even more if futureprojects are included.

GEUS (Denmark), BRGM and IFP (France), OGS andthe University of Rome (Italy), NIVA, RF and SPR(Norway), TNO (Netherlands) and Imperial Collegeand Heriot Watt University (Great Britain).More than 100 research scientists are involved in thesix key research themes:• the integration of a site's geological characteristics

into a geological model;• the development of predictive modelling tools;• experimentation in the laboratory and on-site;• perfecting geophysical and geochemical

monitoring methods;• the development of risk-assessment

methodologies;• coupling CO2 storage with the enhanced recovery

of hydrocarbons.

This network of excellence was launched in 2004with funding from the European Union of 6 millioneuros over five years in the framework of its 6th

Framework Research and Development Programme.It is destined to grow beyond the five-year period with support from other public orprivate sources of funding and by integrating newmembers so as to strengthen European researchcollaboration in this field, whilst promotingcoordination with national research programmes.

The CO2NET networkSet up in 2002 with supportfrom the EuropeanCommission, this thematicEuropean network currentlyhas 65 member organizationsfrom 19 countries. Bringing

together research scientists, developers and end-users of CO2 capture and storage technology, itspurpose is to facilitate exchange and cooperationamongst the various players. French memberorganizations are Air Liquide, BRGM, CEA, CGG,GDF, IFP and Total.

The European InCA-CO2 projectThe InCA-CO2 (International Cooperation Actions inCO2 Capture & Storage) project aims at establishingEuropean know-how in the field of CO2 capture andstorage on the international scene.Since 2005, the project has gathered around IFP sixEuropean research centres: BGS (Great Britain),BRGM (France), GEUS (Denmark), OGS (Italy), Sintef(Norway) and TNO (Netherlands), as well as fourmajor industrial partners: Alstom, BP, Statoil andVattenfall (electricity leader in Sweden, very wellestablished in Germany). This group constitutes astructure for cooperation, dialogue and exchange, onwhich the European Commission will rely in itsinternational negotiations. A number of orientationsare to be developed simultaneously: identify theopportunities for future cooperation betweenEurope and its international partners (Australia,Canada, the United States and Japan), provide all theinformation required by the Europeanrepresentatives with seats in internationalorganizations, such as the CSFL (CarbonSequestration Leadership Forum) and develop acoherent point of view on international activityregarding CO2 capture and storage so as to promotefuture European policies. The InCA-CO2 project hasobtained funding from the European Union.36

CASTOR: this European project, scheduled to run 2003-2008 and integrating the entire CO2capture-transport-storage chain, is also broadening its scope to include hydrogen storage. Itincludes many sub-projects with the objectives of installing real demonstration pilots,technical optimization of the chain, risk quantification and working out scenarios that arerealistic both technically and economically.Partners: IFP (coordinator), Alstom Power, BASF, BGR, BGS, BRGM, Elsam, ENI, Gaz de France,GEUS, GVS, Imperial College, Mitsui Babcock, NTNU, OGS, Powergen, PPC, Repsol, Rohoel, RWE,Siemens,Sintef,Statoil,TNO,the University of Stuttgart,the University of Twente and Vattenfall.http://www.co2-castor.com

CCP (CO2 Capture Project, USA): this R&D project, piloted by a group of industrial players, is devotedto lowering the costs associated with capture, separation and geological storage.Partners: BP, BR, Chevron Texaco, ConocoPhillips, DOE, EnCana, ENI, Klimatek NorCap, NorskHydro, Shell, Statoil and Suncor.http://www.co2captureproject.org/

CMI (Carbon Management Initiative): studies that address CO2 sequestration and measurethe risk of migration.Partners: Alberta Energy and Utilities Board, EUB and Princeton University.http://www.eub.gov.ab.ca/bbs/products/newsletter/2002-01/feature_02.htm

CO2GEONET: the European network of excellence dealing with the geological storage of CO2that seeks to promote integration and coordination amongst research teams.Partners: BGS (coordinator), BGR, BRGM, GEUS, IFP, Imperial College, NIVA, OGS, RF, SPR-Sintef,TNO, Heriot Watt University and the University of Rome.http://www.co2geonet.com

CO2NET:a thematic European network devoted to CO2 capture and storage that seeks to promoteexchanges and cooperation amongst the various players.Partners: Technology Initiatives (coordinator), 65 member institutions from 19 Europeancountries.http://www.co2net.com

CO2STORE: a study of long-term behaviour on the Sleipner site and of the feasibility of storage inaquifers on four other sites in Europe.Partners: BGR, BGS, BP, BRGM, EnergiE2, Exxon-Mobil, GEUS, Hydro, IFP, IEA, Industrikraft,GHG, NGU, Schlumberger, Sintef, Statoil,TNO,Total, Valleys Energy and Vattenfall.http://www.co2store.org/

COAL-SEQ (US DOE Netl, since 2000): CO2 sequestration in deep coal seams.Partners: Advanced Resources International, Alberta Research Council ECBM, BP America,Burlington Resources and the Recopol Project Consortium. The first pilots in the San JuanBasin, USA (Allison Unit operated by Burlington Resources, CO2 injection since 1995, andTiffany Unit operated by BP).Work with Recopol and ARC.http://www.coal-seq.com/

List of the mainprogrammes

throughout the world

37

CSI (Carbon Sequestration Initiative, 2002-2007, the Massachusetts Institute of Technology): research rangingfrom CO2 capture to all the sequestration techniques (forests, geological reservoirs, deep oceans, etc.).A Consortium made up of Alstom Power, American Electric Power, American Petroleum Institute, AramcoServices, ChevronTexaco, Electricité de France, Epri, ExxonMobil, Ford Motor Company, General Motors andPeabody Energy.http://sequestration.mit.edu

GEODISC (since 1999): the Australian Petroleum Cooperative Research Centre (APCRC) is engaged in drawing up alist of potential reservoirs in Australia, the in-depth study of a few sites with modelling, studying reservoirs ofCO2 analogues, developing a monitoring programme on a pilot site (starting in 2003) and quantifying risks.Partners: BHPP, BP Amoco, Chevron, Gorgon, Shell and Woodside.http://www.apcrc.com.au/Programs/geodisc_res.html

GEOSEQ (2000-2015,DOE-NETL,National Energy Technology Laboratory): the purpose of this programme is to makelarge-scale sequestration of CO2 in geologic formations a reality by 2015. This project has been using a pilotsite in Texas, the Frio Brine Pilot, since 2002.Partners: the Alberta Research Council (ARC), BP-Amoco, Chevron, IFP, Pan Canadian Resources, StanfordUniversity, Statoil,Texaco and the US Geological Survey.http://esd.lbl.gov/GEOSEQ/

GESTCO (Geological Storage of CO2, 2000-2004): a European Union project to draw up a list of CO2 storagecapacities in Europe.Partners: GEUS (the Geological Survey of Denmark and Greenland) coordinator, BGR (the Federal Institute forGeosciences and Natural Resources, Germany), BGS (British Geological Survey), BRGM (French GeologicalSurvey),Ecofys (Netherlands),GSB (the Belgian Geological Survey), IGME (the Institute for Geology and MineralExploration, Greece), NGU (the Geological Survey of Norway) and NITG-TNO (the Geological Survey of theNetherlands).www.nitg.tno.nl/projects/eurogeosurveys/projects/GestcoWeb

ICBM (EU): the development of characterization and modelling tools to improve methane recovery by CO2 injectionin coal.Partners: BP, Deutsche Steinkohle Aktiengesellshaft, IFP, Imperial College London, the University of Delft andWardell Armstrong.

IEA Weyburn Monitoring and Storage Project (2001-2004): CO2 storage in the Weyburn(Saskatchewan, Canada) oilfield in conjunction with enhanced oil recovery.Partners: EnCana (oil company), the Dakota Gasification Company (CO2 supplier), PTRC (PetroleumTechnology Research Center, coordinator of the research project), Canadian and American research teams,European research teams (BGS and Quintessa, UK; BRGM, France; GEUS, Denmark and INGV, Italy).http://www.ptrc.ca

IN SALAH: an industrial project of CO2 storage in Algeria in a gas reservoir nearing depletion. A million tons of CO2per year have been injected since August 2004.Partners: BP, Sonatrach and Statoil.

INCA-CO2 (since 2004): this project aims to establish European know-how regarding CO2 capture and storage onthe international scene.Partners: IFP (coordinator), Alstom, BGS, BP, BRGM, GEUS, OGS, Sintef, Statoil,TNO and Vattenfall.

IPGP (since 2003): a study of the basic mechanisms involved in the evolution of CO2 underground.Partners: IPGP (coordinator), Schlumberger, and Total.http://www.ipgp.jussieu.fr/francais/rub-recherche/programmes/CO2.html

NASCENT (2001-2004):studies of natural CO2 reservoirs in Europe,as natural analogues of CO2 storage.Co-financedby the European Commission.Partners: BGR, BGS, BP, BRGM, IEA-GHG, IGME, MAFI, Statoil,TNO and the University of Rome.http://www.bgs.ac.uk/nascent/.

NGCAS (2002-2004): the Next Generation Capture And Storage project is part of CCP; directed by the EuropeanUnion, it aims to develop a methodology and tools for maximizing CO2 storage; feasibility studies concerningdepleted pools in the North Sea.Partners: BP (coordinator), AEA Technology, BGS, GEUS, IFP and Statoil.

PICOREF (F): the purpose of the project devoted to CO2 storage in reservoirs in France is to prepare industrialdemonstrations of CO2 injection into the subsurface in France (notably hydrocarbon reservoirs and salineaquifers).Partners: IFP (coordinator), Air Liquide, Alstom, Armines (ENSM-SE), BRGM, CFG Services, CGG, Correx, Gaz deFrance,Géostock, Ineris, the Laboratoire des Mecanismes de Transfert en Géologie (LMTG),Magnitude,La SNETand Total.

RECOPOL (EU,2002-2005):a pilot test of CO2 sequestration in a coal seam in Poland.The project includes laboratorytests, building geological models, conducting simulations and technical and socio-economic impact studies.Partners: TNO-NITG (coordination, the Netherlands), Central Mining Institute, Csiro, DBI-GUT, Gaz de France,Gazonor, IEA-GHG, IFP, Jcoal, Shell-RTS and the technological Universities of Aachen and Delft.http://www.nitg.tno.nl/eng/projects/recopol/index.shtml

RITE CO2 Geological Sequestration project (2000-2004):a feasibility study on the geological storage of CO2 in Japan.A test of injection into an aquifer (10,000 tons over 18 months, i.e. about 20 tons of CO2 per day).Partners: RITE and ENAA, the Engineering Advancement Association of Japan.http://www.rite.or.jp/English/E-home-frame.html

SACS : a study of CO2 storage in the Utsira saline aquifer, on the Sleipner site in the North Sea (Norway).Partners:Statoil (coordinator),BGS,BP,BRGM,Exxon-Mobil,GEUS, IFP,Norsk Hydro,TNO-NITG,Sintef,Total andVattenfall.http://www.ieagreen.org.uk/sacshome.htm

The search for a regulatoryframework There is no specific legislation or regulatoryframework today applying to the undergroundstorage of CO2, nor any legal statute relative toCO2 liberated by large-scale combustion plants. IsCO2 a waste substance? If so, should it be classedin the category of industrial waste or in that ofdangerous industrial waste? A number ofregulatory texts offer the beginnings of an answer,but none address the long-term storage of thisgas, designed to avoid its release into theatmosphere. Future texts regulating this activitywill therefore need to integrate the notion of long-term storage, a new concept that mustlegally stipulate the specific duration of storagelasting more than a century. For the moment, thepilot projects call on other texts, such as thosegoverning the underground storage of natural gasor oil exploitation in the North Sea.The legislative problem is different, however,according to its source and whether the CO2 isstored offshore or onshore.

Offshore underground storageToday, storage in the North Sea is regulated by twotexts that deal with the environmental protectionof the marine environment: the LondonConvention (1972, 1996) and the OSPAR Convention(Convention for the Protection of the MarineEnvironment of the North East Atlantic). The aimof these treaties is strictly to protect the marineecosystem from possible pollution; the texts donot take into account that CO2 storage is a meansof reducing emissions. Failing any new legislation,it does nevertheless appear legally possible, underthe OSPAR Convention, to capture gas on thecontinent and then inject it beneath the sea,provided it transits by pipeline - a solution beingstudied today in the United Kingdom.To clarify the situation, a working group that is an

outgrowth of the London Convention has cometogether. It will prepare a list of the different legalpoints of the Convention and of the 1996 Protocolthat could be relevant to CO2 storage, in order to organize a debate around a possible adaptationor future amendments.

Onshore underground storageThis subject is more complex, for it depends on thelaws in force in each country and on the specificstorage site conditions. Storage via enhanced oilrecovery profits from existing laws in this field (eachcountry's mining code covers this type of operation).Injection into an aquifer raises more problems: it relieson regulations applying to the underground storage ofnatural gas, or on laws related to water.The EuropeanDirective concerning landfilling also deserves amention, which defines underground storage in rockcavities as a permanent storage method.This Directivewill have to be adapted if it is to serve as a regulatorybasis, because it does not apply to substances subjectto physical or chemical changes.

The search for a political frameworkA special report on CO2 capture and storagetechnology is being drafted by theinternational scientific authority constituted bythe Intergovernmental Panel on ClimateChange (IPCC). The report will review alltechnical, economic and environmental aspectsin order to assist in decision-making on apolitical level. Steps are thus being taken onthe international scene, within the frameworkof the Kyoto Protocol, to add CO2 capture andstorage as additional tools for combatinggreenhouse effect.The sixth programme of European Communityaction for the environment has identifiedclimate change as a priority field of action andhas planned to establish a Community systemfor the exchange of emission rights. Itrecognizes that the Community has committeditself, between 2008 and 2012, to reducinggreenhouse gas emissions by 8% comparedwith 1990 levels and that, in the long term,greenhouse gas emissions will have to bereduced by some 70% with respect to 1990.

Tradeable* CO2 emission permitsThe 2003/87/CE Directive of the EuropeanParliament and of the Council of 13 October 2003(modified by Directive 2004/101/CE of 27 October2004) establishes a Community system for theexchange of greenhouse gas emission rights: theEuropean Union Emission Trading Scheme (EU-ETS)became effective on 1 January 2005. This system isdivided into two periods, the first from 2005 to2007, the second from 2008 to 2012. Thesetradeable permits* apply, at least for the firstperiod, exclusively to CO2 emissions from fivesectors of activity: the production of energy and of

The Norwegian Statfjord platformin the North Sea that taps anatural gas reservoir in conjunctionwith a CO2 storage project in themarine subsurface.

38

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oil

ferrous metals, the mineral industry (cement andglass works), the manufacture of ceramic goodsand of wood pulp. Starting in 2008, other sectorslike the chemical or aluminium industries mightbe included under the directive.A certain number of emission allowances areallocated for the period to each industrial plantconcerned by the directive. A CO2 allowancecorresponds to one ton of CO2. Each year, eachplant will be required to provide an account of itsactual CO2 emissions. In the case where actualemissions are lower than the annual allowance,the plant will be awarded an excess allowancethat it can either set aside for succeeding years orsell on the market. Conversely, those plants thatemit more CO2 than their annual allowance willbe under the obligation to purchase theallowances they lack on the market, or will beforced to pay an excess emissions penalty of 40 euros per ton of CO2. The system is expected tobe extended to the international market around2008 and the penalties will increase (to 100 eurosper ton), which opens up encouraging perspectivesfor CO2 capture and storage.This European market of CO2 emission rights isstill in its early stages for various reasons: not allthe national allowance plans have yet beenallocated - the industrial players are discovering asystem of management of CO2 allowances that isnew to them - and the European exchange thatwill link all the national markets is not yetoperational. Today, information on the price of aton of CO2 comes from traders who recordbilateral forward transactions.The price of the European CO2 allowance has beenrising continuously since 1 January 2005, when itwas 5 euros/t CO2; only six months later, it wasmore than 20 euros/t CO2.According to the European Commission, 6.5 billionallowances - and thus as many tons of CO2 - havebeen allocated for 2005-2007 to approximately11,500 European industrial sites. Ten percent of

these will probably be exchanged, representing anannual market of 200 to 300 million tons andsome 20 billion euros at European scale.

An important choice for Society How will the general public react to massive CO2storage in France? The few polls that have beenconducted reveal a total lack of understanding ofthe technology. When the public does have someknowledge of the issue, questions concerningfears over life expectancy of the facilities or risks ofleakage are repeatedly voiced. A considerableeffort in favour of public awareness and dialogue -in particular with the population residing in thevicinity of the projected sites - should thereforeaccompany the approach adopted for the varioussocietal players, with guarantees of transparencyand independent oversight. The management ofCO2 storage will need to be conducted underconditions of total safety, ones that public opinionregards as satisfactory.

FutureGen (United States) and HypoGen (Europe)The fear of seeing CO2 capture and storage beingused as an alibi for failing to develop alternativeenergies or to control energy use is one of themain arguments used against its development.Conversely, it can be declared that the obligationunder which the users of fossil fuels are placed toeliminate their emissions will, by making thesource more expensive, promote the developmentof renewable forms of energy and of intensifiedenergy conservation. It is important to resituatecapture and storage in the multiple energy sourceperspective. Setting up an energy stream based onthe capture and storage of CO2 can be illustratedby the FutureGen initiative of the American

Department of Energy (DOE), the projectcoordinator. Launched in 2004 in collaboration with industrial partners,this programme's objective is to extract hydrogenfrom coal, for which the United States holds 23%of the world's reserves. DOE has been allocated abillion dollar budget for building over the next tenyears a 275-MW plant that will use gasified coal to produce electricity and hydrogen, all this withno pollution, since the CO2 released will becaptured immediately and stored underground.With HypoGen, Europe has launched a similarprogramme: 1.3 billion euros will be devoted tocreating a European pilot site that produceshydrogen from gasified coal or from natural gas.

39

Flow sheet of theprinciple underlying theFutureGen programme Using coal gasification,the aim is to generate bothelectricity and hydrogen without releasing any carbondioxide, since this is to be captured immediately and stored in deep saline aquifers,hydrocarbon reservoirs nearingdepletion and coal seams.

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A number of the national players take a key partat European scale in research devoted to CO2capture and its long-term storage, and this has beenthe case ever since the first European project,“The underground disposal of carbon dioxide”(Joule II Project 1993-1995), which allowed thefeasibility of this technology to be demonstratedand in which BRGM took part. For over ten years,France has thus been involved in a majority ofEuropean projects and also in certain internationalprojects dealing with geological storage, particularlythose associated with the first industrialapplications (Sleipner and Weyburn).

In 2001, a national forecasting study on energypolicy strategy conducted by French researchinstitutes (including CEA and CNRS) prioritized,amongst the different measures at issue, thetechnologies for CO2 capture and storage,considered a strong option both for tackling theproblems of climate change and for boostingindustry. This work, supported by a dynamicscientific community and motivated industrialplayers, has brought the concerned parties closertogether to form a national network that is active inboth European and international projects. Thecreation of Club CO2, French participation in theInternational Energy Agency's programme ongreenhouse gas reduction (IEA-GHG) and, lastly,involvement in the Carbon Sequestration LeadershipForum (CSLF) constitute the principal landmarks inthis process.

National projects• A network was formed to study geological

storage: it involves a consortium of gas and oilcompanies (Total, GDF), an engineering company

(Géostock), research centres (BRGM, IFP andCNRS) and a number of French universities.This group, backed by the RTPG (Réseau desTechnologies Pétrolières et Gazières - Network ofOil and Gas Technologies), participated from2002 to 2004 in a project on CO2 Capture inReservoirs (PICOR) as well as in a feasibility studyof a CO2 storage pilot in a hydrocarbon field.Also under study is a clean coal project based onthe storage possibilities for the Gardanne(Bouches-du-Rhône Département) and Carling(Moselle Département) plants. In 2005, theseefforts will continue within the Picoref project.

• With respect to CO2 capture and transport,several projects are being implemented by theindustrial players in the sector (Air Liquide,Alstom, Arcelor, EDF, GDF, Total, and Lafarge),with support from Ademe (French Agency forthe Environment and Energy Management).Topics addressed are the calcium cycle, cryogenicseparation, oxy-fuel combustion, solventscrubbing, chemical looping, etc.

• The IPGP (Institut de Physique du Globe de Paris- Paris Geophysical Institute) joined in 2003 withtwo major players in petroleum research to setup a research programme on CO2 capture andunderground circulation; six laboratories and 25 research scientists are involved in this projectwith support from Ademe.

• The Metstor programme, funded by Ademe andinvolving a large number of partners (Inéris, GDF,Géostock, Cired, IPGP, ENSMP, BRGM, IFP and theUniversity of Pau), is due to be launched in 2005.Its purpose is to design a decision-support toolfor selecting storage sites in France.40

The project devoted to CO2 seques-tration in reservoirs in France hasthe assigned objective of preparingindustrial demonstrations of CO2injection into the French subsurface(notably into hydrocarbon reservoirsand saline aquifers). It was initiatedby the Ministry for Industry in theframework of the Network of Oil

and Gas Technologies (RTPG) and bya consortium of French firms anduniversities. Its objective is to pro-vide descriptive information aboutCO2 storage at specific geologicalsites and to identify pilot demon-stration sites in France. Already, theParis Basin emerges as a potentialcandidate for capturing the CO2 pro-

PICOREF

Formation Area Mean netthickness Porosity Total pore

volume

Storagecapacity(aquifer)

Storagecapacity(traps)

km2 km km3 Mt CO2 Mt CO2

Bundsandstein 21 000 0,200 0,1 420 17 640 529

Keuper 27 500 0,025 0,15 103 4 331 130

Trias 48 500 0,225 523 21 971 659

The storage capacityof Triassic aquifers,

which cover morethan 48,000 km2,amounts to some

22 billion tons of CO2.The red dots mark

the main CO2emission sources.

The topography ofthe bedrock underlying

the main sedimentarybasins is indicated

by contour linesfor depths greater

than 1000 m.

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• Lastly, CO2 capture and storage count amongthe priorities of the National Agency forResearch (ANR) recently created in February2005. Moreover, the future Agency for IndustrialInnovation might assist in carrying outindustrial demonstration projects in this field.

European ProjectsResearch centres (BRGM and IFP) together withsome industrial players (GDF, Alstom and Total)have also been taking part in European projectssince 1993: Joule II, SACS, Gestco, Nascent,Weyburn, Recopol, Castor, CO2Store, etc. France isalso participating in CO2Net, a thematic Europeannetwork devoted to CO2 capture and storage, aswell as in CO2GeoNet. This latter network ofexcellence devoted to geological storage iscoordinated by the British Geological Survey, withthe participation of BRGM and IFP.

International involvementIn addition to its participation in the InternationalEnergy Agency programme on greenhouse gasreduction (IEA-GHG), France is a member of theCarbon Sequestration Leadership Forum (CSLF), aninternational forum initiated by the United Statesto promote efficient and cost-effectivetechnologies for CO2 capture, transport andstorage under satisfactory safety conditions. CSLFalso aims to boost development of the concept byestablishing an appropriate political andregulatory environment. The members of thisforum are South Africa, Germany, Australia, Brazil,Canada, China, Colombia, the EuropeanCommission, France, Great Britain, India, Italy,Japan, Mexico, Norway, the Netherlands, Russia

and the United States. CSLF plays the role ofreference authority and awards products the sealof approval.

In 2005, for the first time, the Gleneagles (GB) G8summit devoted its meeting to the combatagainst global warming, stressing the need forcooperation amongst developed and developingnations - particularly China and India - who aredestined to become the largest emitters of CO2because of their industrial development basedmainly on coal.

Progressively a worldwide consensus is emergingaround the necessity to develop and adopt,in the shortest timescale possible, the technologyfor CO2 capture and storage. Today, it is clearlyonly by combining energy savings, thedevelopment of renewable energy sources andCO2 capture and storage that we may hope tosucceed in stabilizing CO2 concentrations andthereby avert the threat of massive climateupheaval.

41

duced by industry and storing it inits subsurface saline aquifers(Dogger and Triassic). These aquiferscontain zones that are relativelywell known, such as those examinedin connection with geothermalenergy or oil. They also have theadvantage of being located directlybeneath the CO2-producing zones,

thereby cutting down on transportcosts. Lastly, the aquifers have con-siderable storage capacities: about4 billion tons for the Dogger and 22 million tons for the Triassic. In2005, the project is to examine twotypes of site in the Paris area: a pro-ducing hydrocarbon reservoir and adeep saline aquifer.

Formation Area Mean netthickness Porosity Total pore

volume

Storagecapacity(aquifer)

Storagecapacity(traps)

km2≈ km km3 Mt CO2 Mt CO2

The Paris geothermal reservoir 2 484 0,020 0,15 7 215 0,43

Dogger 15 000 0,100 0,1 150 4 320 8,64

The Doggergroundwater reservoiroffers a storagecapacity of 4 billiontons of CO2.Red dots mark the main industrialzones emitting CO2.

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Club CO2 was formed in 2002 on the initiative of Ademeand with the support of IFP and BRGM, the latter acting assecretary. It represents a key element in the organization ofFrench research in the field of CO2 capture and storage. It isin fact a response to the need to more effectively federatenational efforts, whilst giving them better public visibility.Under the presidency of Ademe, the Club gathers togetherthe major concerned players in the industrial sector and inresearch. A clearinghouse for dialogue, information andinitiatives amongst its members in the area of studies andtechnological developments concerning CO2 capture,

transport and storage, the Club encourages cooperation at a national level betweenthe public and private sectors, and several research projects have been started underits initiative. Theme-based groups have been formed to collect all availableinformation on this field. The data serve to identify directions where progress shouldbe made and to make recommendations to decision-makers and funding bodies toinitiate multidisciplinary work. Lastly, it plays the role of showcase for promoting theFrench technological know-how within the European and international arena.

As of 1 September 2005, Club CO2 will count the following as members: Ademe, AirLiquide, Alstom, Arcelor, BRGM, CNRS, EDF, GDF, Géostock, IFP, Lafarge, SARP Industrieand Total.

42

LAFARGE

CENTRE NATIONALDE LA RECHERCHESCIENTIFIQUE

The Missions of Club CO2

• Identify the broad orientations and the major challenges to be targetedby scientific and technical programmes;

• Make recommendations to decision-makers and research funding bodiesthat inter-disciplinary efforts should be initiated and expanded;

• Conduct forecasting studies, based notably on an activity of techno-logical and strategic oversight on the theme;

• Promote French technological know-how on the European and interna-tional arena;

• Encourage partnerships between research teams in the public and privatesectors;

• Foster contacts and information exchange amongst all players involvedin the field: industry, research institutes and government authorities;

• Disseminate and communicate information: data banks, websites,forums, etc.;

• Organize workshops around specialized themes.

In 2004, two thematic groups were formed within Club CO2, one on thecapture and transport of CO2, the other on its geological storage. The aimof these two working groups is to propose priority directions for researchand development in the medium term for France, so as to promote andcoordinate the nation's R&D for each of the “technological building-blocks” needed to ensure the whole programme's success, whilstremaining coherent with European and international initiatives.

The capture andgeological storage of carbon dioxideemitted by industrialand energy-producingactivities, in conjunctionwith energyconservation and the developmentof renewable energysources, emerges as a self-evident optionfor reducing greenhouse gases.

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The French Agency for the Environment and EnergyManagement (Ademe), a public entity, participates in theimplementation of public policy in the sectors ofenvironment, energy and sustainable development. It makesits expertise and advice capabilities available to companies,local communities, public authorities and the public at largeand assists them in funding projects in five areas: waste,ground preservation, energy efficiency, renewable energysources, and air quality and noise control, and in advancingin their actions supporting sustainable development.

In the context of its missions, Ademe contributes toreducing greenhouse gas emissions of human origin andhas earmarked CO2 capture and storage as one of itsresearch priorities. In this context, it takes part in federatingand structuring national efforts in the field, with thecreation in 2002 of Club CO2. Ademe supports largenumbers of projects and initiatives concerning all aspects ofthe capture/transport/storage technological stream, anddevotes special attention to socio-economic andenvironmental impacts in a sustainable developmentperspective.

The Bureau de Recherches Géologiques et Minières (BRGM),the national geological survey, is a public entity that ensuresa triple mission: research, expertise and internationalcooperation. Its objectives are, on the one hand, to gain anunderstanding of geological processes, to develop newmethodologies and to produce and disseminate pertinent,high-quality data and, on the other, to make the necessarytools available for policies concerning the management ofthe surface, subsurface and resources, the prevention ofnatural risks and pollution, and land-use development.

BRGM is among those who have played a pioneering role inresearch addressing CO2 storage in geological formations.Between 1993 and 1995, it took part in the first Europeanresearch project on the feasibility of the concept, the Joule IIproject, i.e.“The underground disposal of carbon dioxide.”Since then, it has been contributing actively to many otherEuropean and French projects, including SACS, Gestco,Nascent,Weyburn, CCP Samcards, Picor, Castor, InCA-CO2,Ulcos and Picoref. It plays a key role in the management ofthe CO2GeoNet European network of excellence, is an activemember of the thematic CO2Net European network, and issecretary of the French Club CO2. BRGM has moreparticularly received recognition for it competences inmodelling the chemical interactions between injected CO2and the host rock. Its research concerns, more widely, thechoice and characterization of storage sites, predictivemodelling and monitoring methods in order to guaranteethe safety of storage sites.

43

IFP is a centre for research, technological innovation andtraining in the fields of energy, transport and theenvironment; its vocation is to develop knowledge andtechnologies that make it possible to supply the energy tosatisfy the growing global needs for mobility, in asustainable manner and one that respects the environment,throughout the 21st century.

Solving problems concerning CO2 capture, transport andstorage represents one of its five strategic priorities.The actions undertaken aim at reducing the CO2 releasedfrom fossil fuels used in transport and industry bydeveloping engines and fuel that offer greater performanceand less pollution.They also aim at eliminating emissions bythe capture and long-term, underground storage of the CO2given off by electrical power plants and high-poweredindustrial facilities. In this area, IFP is actively participating inmany French and European projects covering all aspects ofthemes ranging from capture through to geological storage.In particular, IFP is coordinating a number of projectsincluding Castor (a European project aiming to cut the costof CO2 capture by half and to validate the concept ofgeological storage), InCA-CO2 (International CooperationActions on CO2 capture and storage, a European project thatseeks to promote European know-how in the field on theinternational scene) and Picoref (Capturing CO2 in reservoirsin France).

Adsorption: a surface phenomenon whereby gas or fluid molecules bind to the solid surfacesof certain substances according to variablyactive processes. Clays and zeolites areparticularly effective natural adsorbent media;active carbon is an excellent adsorbent.

Aquifer: a permeable geological formation that contains water.The most superficial aquifers contain fresh water used for drinkingsupply. Aquifers at greater depth contain brine that is totally unsuitable for humanconsumption.These are called deep salineaquifers. In places, aquifers contain oil and gas deposits where the pore water has locally been replaced by hydrocarbons.They may also contain deposits of pure CO2of natural origin.This is the basis for the idea of storing CO2 in the pores of rocks, thusmimicking natural CO2 deposits.

CO2 (carbon dioxide): one and a half times as heavy as air, CO2 does not exist in liquid form underatmospheric pressure conditions; one ton of CO2contains 0.27 tons of carbon.

CO2 sink: systems found essentially in seas, forests,and the ground that naturally absorb part of theCO2 released into the atmosphere.

ECBM, or Enhanced Coal Bed Methane: a process of enhanced methane recovery, making it possible to tap the natural gas that is trappedin the coal.

EOR, or Enhanced Oil Recovery: a process of stimulated oil retrieval that enhances theproduction of oil deposits.

GHG, or greenhouse gases.The two main gasesresponsible for the greenhouse effect are watervapour (H2O) and carbon dioxide (CO2).The other main “natural”greenhouse gases aremethane, CH4, nitrogen protoxide, N2O and ozone, O3.The main industrial greenhouse gases arehalocarbons such as HFC, PFC and CFC, and sulphurhexafluoride, SF6, which absorb infrared rays very strongly, much more so than CO2, and mayremain in the atmosphere for very long periods of time, up to 50,000 years.

Gt (gigaton): 1 Gt = 1 billion tons.

IPCC : the Intergovernmental Panel on Climate Change.This group was formed in 1988 by the WorldMeteorological Organization (WMO) and the UnitedNations Environment Programme (UNEP). Its role isto evaluate pertinent scientific, technical and socio-economic information with a view to understandingthe risk of climate change due to man.

Monitoring : the quantitative and qualitativesurveillance of natural environments or industrial operations using instrumentalnetworks in conjunction with predictivemodels.

NIMBY, or “Not In My Backyard”: a phenomenon ofsocietal resistance towards any project near tohome that might threaten, or is perceived as apotential threat to, the individual's quality of life.

Partial oxidation: a process called on in industrialinstallations to produce synthesis gas from various fuels (coal, biomass, heavy-grade oil, etc.)and oxygen.

ppmv: parts per million by volume; a way of describing the content of a given substance(carbon dioxide, for instance) found in a gaseoussample; one of these units corresponds to 1 cm3 per m3.

Steam reforming: a process used to producesynthesis gas from light fuel - natural gas - andwater vapour. Steam reforming of natural gasmakes it possible to obtain the highestconcentrations of hydrogen.

Synthesis gas (or syngas): an intermediate product,a mixture of carbon monoxide, CO, and hydrogen,H2, resulting from a partial oxidation or fromsteam reforming. Synthesis gas is used in manyindustrial applications to generate energy(electricity or hydrogen) and chemical substances(synthetic fuels).

Tradeable permits: a system enabling nations (or individual firms) that have cut back theiremissions beyond the stipulated objective or allowance to sell the corresponding emissionrights to another nation (or firm) that is unable to reduce its emissions enough toachieve its objective.

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www.clubco2.netThis website aims to make essential data and information available to research scientists, to professionals in the sector, as well as to a wider audience

(scientists, journalists, teachers and environmentally-involved NGO's, etc.) on carbon dioxide capture and storage,as embodying one solution to global warming.

This site's purpose is to provide an opportunity for exchange, to encourage cooperation nationally between the public and the private sectors.

It is a showcase to promote French technological capabilities on offer in the European and international arenas.

Main topics dealt with on the site:The “Greenhouse Effect”

The capture and storage of CO2Research & Development

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