solar thermal vision 2030 060530

8/8/2019 Solar Thermal Vision 2030 060530

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This vision document was prepared by the initiator group of ESTTPTeun Bokhoven, Nigel Cotton, Harald Drck, Ole Pilgaard,

Gerhard Stryi-Hipp, Werner Weiss and Volker Wittwer

with valuable contributions fromAris Aidonis, Riccardo Battisti, Chris Bales, Maria Carvalho, Jan-Olof Dalenbck, Simon Furbo, Hans-Martin Henning, Soteris Kalogirou, Peter Kovacs, Dirk Mangold, Mario Motta, Collares Pereira, Christian

Roecker, Matthias Rommel, Thomas Schabbach, Claudia Vannoni, Grzegorz Wisniewski

ESTTP Secretariatc/o European Solar Thermal Industry Federation (ESTIF)

Renewable Energy HouseRue dArlon 63-65, B-1040 Brussels

Tel: +32 2 546 19 38, Fax: +32 2 546 19 [email protected], www.esttp.org

ESTTP is supported by

Solar Thermal Vision 2030Vision of the usage and status of

solar thermal energy technology in Europeand the corresponding research topics

to make the vision reality

First version of the vision document for the start of the

European Solar Thermal Technology Platform

(ESTTP)

May 2006


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Solar Thermal Vision 2030 May 2006 Page 2

European Solar Thermal Technology Platform (ESTTP)

Executive summary

Without any question, solar thermaltechnology is already a maturedtechnology. 30 years of developmenthave led to efficient and long lastingsystems. However, today solarthermal energy is only used in a smallpercentage of European buildings,usually for domestic hot water heatingin private houses. A growing share ofthe installed systems provide

additional support of room heating,covering already typically up to 30%of the total heating requirements of abuilding in Central Europe. Some largesolar thermal systems are installed,which provide domestic hot water formulti-family buildings, hotels,

hospitals and similar buildings. A fewvery large solar energy systems aredelivering heat for district heating,sometimes by using huge seasonalstorages, which are heated by thesolar collectors in summer and whichdeliver this heat for room heating inwinter. There are also somedemonstration systems installed toproduce high temperature heat forindustry or to assist cooling machinesup to now.

The most important reason for not

using more solar thermal energytoday is the low (and subsidized) pricefor fossil fuels. However, from 1998 to2005, the oil price increased by 23%

p.a. on average. Further there aregrowing doubts over the security of oiland gas supply since the Russian-Ukrainian gas quarrel at the beginningof 2006. And a growing number ofexperts are proving evidence that weare near reaching peak-oil, afterwhich oil supply will decline due tophysical reasons. In addition, theurgency to reduce the use of fossil

fuels in order to reduce emissions ofgreenhouse gas and to limit climatechange becomes more and moreobvious. For all these reasons a fasttransition to an energy structurebased on renewable energy is ofutmost importance.

Solar Thermal Energy is an importantalternative to fossil fuels with a hugepotential. In 2005 approximately10 GWth of solar thermal capacitywere in operation in Europe. This

capacity could well be increased to atleast 200 GWth by 2030, when solar

thermal energy will be used in themajority of European buildings. Thetypical share of solar thermal energyin meeting the heating and coolingdemands of a single building will beincreased dramatically to more than50%, and up to 100%. And newapplications will be developed, e.g.solar thermal systems that provideprocess heat for industrial use.

Although matured solar thermaltechnologies are available already,there are further developmentsneeded to provide adjusted productsand applications, reduce the costs ofthe systems and increase market

deployment. Turning solar thermalinto a major energy resource forheating and cooling in Europe by 2030is an ambitious but realistic goal,which is well achievable providedthe right mix of research &development, industrial growth andconsistent market deploymentmeasures is applied.

About 49% of final energy demand inEurope is used for heating and coolingrequirements, mainly in buildings. Onthe basis of a strong reduction of

energy demand through energyefficiency measures, solar thermalenergy will be the most importantenergy source for heating and coolingin new buildings and in the existingbuilding stock by 2030. Already today,state-of-the-art buildings areconstructed that are fully heated by

solar thermal energy.

Solar thermal systems will look verydifferent in the future. Solar thermalcollectors will cover, together withphotovoltaic modules, the entiresouth-oriented roof area of buildings.Roof windows will be integrated. Thestorage tank will be able to store thesolar heat over weeks and months,but will not be too large. The solar

thermal energy system will providedomestic hot water, room heating inwinter and room cooling insummertime, thus greatly increasingthe overall comfort of the building.

Important further solar thermalapplications will be available: large

systems for multi-family houses,hotels, hospitals etc. In small cities,


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every building will have its own solarthermal system; in large cities, solarthermal energy will be used withindistrict heating systems. Solarthermal systems will provide processheat of up to 250C for industrial

requirements. Solar thermal sea waterdesalination will be important, e.g. forthe Mediterranean countries.

In a few years, solar thermal systemswill be cost competitive, due toreduced costs for solar heat and

increased prices for fossil fuels. Theeffect of large-scale use of solarthermal will decrease greenhouse gasemissions as well as the highEuropean dependency on importedfuels. Solar thermal energy willconsequently help to keep the energy

costs within acceptable limits forconsumers and industries. In addition,a large number of new and future-

oriented jobs will be created mainly insmall and medium size enterprises,due to the decentralised nature of thetechnology.

The European Solar ThermalTechnology Platform (ESTTP) will playa very important role in the future

development of solar thermal inEurope by:

specifying the vision of theuse of solar thermal energy in2030

working out a strategicresearch agenda which is

necessary to achieve thevision

accelerating the technologicaland market development ofsolar thermal technologies

advising industry, researchersand politicians about the mostappropriate and effective

steps to develop thetechnology, industry andmarkets for solar thermal in

order to implement the visionand the strategic researchagenda

The goal of the ESTTP is to help theindustry, the research community aswell as public funding bodies to focuson high-impact topics with the aim ofsustaining the European solar thermalsector's global technologicalleadership.


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1 Introduction

A major part of the energy use in theEU is related to applications in heatingand cooling which operate attemperatures far below 250C. Mostof this heat could be provided by solarthermal energy.

About 49% of final energy demand inEU25 is used for heating purposes.80% of that demand is used forapplications below 250C. These

figures reflect the enormous potentialfor solar thermal as the maintechnology to replace traditional fuelsused for heating and cooling.

Heating

49%

Transport

31%

Electricity

20%

Fig. 1: Breakdown of final energyconsumption in Europe

In order to fully utilise the potential ofthe technology, there must be a

structural approach towards researchand development along withimplementation aspects. Solarthermal will generally be produced onsite and not transported over longdistances. Therefore, solar thermalneeds to blend into the existingprocesses, installations and buildings.

In new buildings, solar thermal energycan cover 100% of heating and

cooling requirements. In the existingbuilding stock, solar thermal cancover more than 50% of the heatingand cooling requirements, and up to100%, depending on the specific

conditions. For various industrialprocesses, the solar thermal potentialis hardly used today, but this isexpected to change drastically oncethe turning point is reached and price

levels of traditional fuels will exceedsolar thermal prices.

This vision document describes thegoals and targets for solar thermalenergy and provides an overview ofthe technological perspectives andneeds of research and development tofully utilise its benefits as a majorenergy source in 2030. The papergives some ideas as to the sectors in

which solar thermal energy will beused, to what extent, with whichtechnology and in what types ofapplications.

2 Objectives and scope

2.1 The nature of thetask: heating andcooling without theuse of fossil fuels

In 2030, it is very likely that due totheir limited availability fossil fuels willbe too expensive to be used forheating and cooling buildings. Theneed for drastic reductions in theconsumption of fossil fuels for energy

requirements in buildings andindustrial processes will lead to

energy efficiency measures andenergy savings in general. Howeverthese measures alone will not besufficient. The large-scale deploymentof renewable energies and especiallysolar thermal is the essential factor toguarantee a sustainable supply ofheating and cooling.

The proportion of CO2-neutral heatingsystems using biomass, and in someregions geothermal, will rise

significantly in the future. The existingbiomass and geothermal potential will

Solar thermalenergy offers theavailability tocover a substantial

part of the EUenergy use in acost effective and

sustainable way


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however not be sufficient to cover theentire heating and cooling demands,especially since biomass will also beneeded to cover the requirements ofthe transport and electricitygeneration sectors.

In the vision described in thefollowing, the efficient use of energysources, by means of heat insulationof buildings for instance, but also byusing passive solar energy throughwindows, as well as the extensive use

of biomass and geothermal energy, istaken for granted and not givenspecific mention. Therefore only theactive solar thermal energy systems,which cover an important part of theremaining energy demand, aredescribed.

2.2 A vision for 2030:solar thermal energysystems will provideup to 50% of lowtemperature heatingand cooling demand

For new buildings, the vision is toestablish the completely solar-heatedbuilding as a building standard by2030. This concept already exists andthe functionality of such systems hasbeen proven. The only requirementsare a sufficiently large area for thesolar collector and a seasonal heatstorage system that uses the energyobtained in summer to heat thebuilding over the winter months.Already in 1989, a house using solarenergy for 100% of its heatingrequirements was constructed inOderburg, Switzerland. This was

followed by other solar energyhouses, for example the Self-Sufficient Solar House in Freiburg in1991. A growing number of buildingsconstructed in Europe are heated 50%to 100% by solar thermal energy.

In the future, new compact long termstorage technologies will significantlyreduce the space demand required ofheat storage devices. High-efficiencysolar collectors will be developedfurther, which will increase the energygained from the winter sun. Additonalcomponents and the design of such

systems have to be further improved

to allow their use in the widestpossible spectrum of applications, aswell as their integration in the buildingand in the energy system.

For the existing building stock the

challenges are even greater. Thebuilding envelope, the location,orientation and access to energynetworks determine the possibilities to

reduce the heating demand and toproduce the entire heat demand bysolar thermal energy. Howevertechnologies and products todrastically reduce the energyconsumption are already available.The aim of the solar thermal branch isto cover substantially more than 50%of the remaining heating demand withsolar thermal energy in refurbished

buildings.

Solar thermal energy will not only bethe most common type of heating

system in residential buildings butalso in public, commercial andindustrial buildings, and it will supplyheat for domestic hot water as well asfor room heating and coolingrequirements.

For the industrial and agriculturalneeds of process heating and cooling,

the challenges are similar. Due toincreasing prices of fossil fuels and

growing restrictions of greenhousegas emissions, the industry isincreasingly adapting to review itsenergy-consuming processes. In thatrespect, there is growing potentialwhich will require further appropriatetechnical solutions based on solarthermal technology in order to tap theenormous potential for heat attemperatures of up to 250C.

Approximately 40% of the finalenergy consumption in the EU isaccounted for by the low-temperatureheating segment in new buildings, theexisting building stock, and industrialrequirements in process heating andcooling. It is in this segment that theEuropean Solar Thermal TechnologyPlatform is operating.

It is expected thatin the comingyears solar thermalwill become the

most importantsource of energyfor heating andcooling buildingsand will play animportant role in

providing(industrial)

process heat


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2.3 The potential forinnovation has beenunderestimated

Up to now, solar thermal technology

has no high priority in European andnational R&D strategies and thereforeonly very limited financial resourcesare provided for R&D in this sector.The reason is that in many circles,solar thermal energy systems areregarded as a low-tech technology

with little potential for development.But the huge potential of energyproduction and the huge potential oftechnical development of solarthermal technology described in thisvision document make it evident thatsolar thermal technology is as yet

dramatically underestimated.

Already in recent years, impressivetechnological developments have been

made. All components of solarthermal systems were improved, newconcepts, materials and new types ofproduction were developed in order toincrease efficiency, quality and lifetime of the systems, as well as toreduce costs. For example, solarcombi-systems (solar thermal systemsfor combined domestic hot water

provision and space heating) havebeen significantly improved in theirlevel of efficiency and reliability, aswell as in the level of integration ofcollectors into the roof cladding orfacades and of the integration of solarenergy systems into conventionalheating technology.

Now we have to start to fully exploitthe great potential for innovation ofsolar thermal technology in a strategic

way. This applies to all componentssuch as solar collectors, storages,

controllers, pumps, securityequipment etc. as well as systemdesign, integration in conventionalheating systems and the buildingenvelope. In addition, the newapplications such as process heat and

cooling have to be further developed.

2.4 The high variation ofgeographicalconditions has to beconsidered

The different intensities of solarradiation and the different demandsfor domestic hot water, room heatingand cooling throughout Europe lead tovery different solar thermal systemsand applications. This represents amajor additional challenge for thedevelopment of the technology, butalso brings more dynamism into theprocess. Other than electricity, heatcannot be transported over large

distances, therefore solar thermalenergy has to be produced near theloads, and the applications have to beadjusted to the various existingheating and cooling equipment andstructures.

The vision and the strategic researchagenda for solar thermal technologyhave to take into account thegeographical and climatic variation

across Europe, and have to guaranteethat adjusted solutions are developed.Mediterranean heating and coolinginstallations have differentrequirements than Scandinavian ones.Covering cooling demand is of priorityin the south, and heating demand inthe north of Europe.

3 Solar thermal energy in 2030

By the year 2030, specific solutionswill be developed for new buildings,for the existing building stock, and forother applications such as industrialneeds and cooling. Solar thermalenergy will be used in stand-alonesingle family houses as well as in

multi-family houses. In urban areas, agrowing proportion of buildings will beheated by district heating systemswith seasonal storages, which areheated up to 100% by solar thermalenergy.

Highly efficient,innovative andintelligent solarthermal energy

systems providinghot water, heatingand cooling will beavailable, and will

offer a high level ofreliability andcomfort


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3.1 Solar vision for newbuildings: the ActiveSolar Building

New buildings offer the chance of

optimising building architecture byproviding a large solar proportion ofenergy usage, minimum heat loss,efficient ventilation and optimalintegration of large solar collectorareas. Integrated building planningoffers a high level of comfort in room

temperature conditioning by usingsurface heating and solar coolingsystems. The Active Solar Building willbe fully heated by solar thermalenergy.

There are different ways to achievethe goal of fully heated buildings inSouthern as well as in Central andNorthern Europe. Active solar thermalenergy systems could be integrated

into the walls, thus efficientlyminimising the heating requirementswhilst providing an active and efficientflow of heat energy into the building.In summer, the heat energy can beused for cooling, as required. Solarcollectors on the roof provide heatingof the domestic water. As analternative to wall-integrated active

solar energy systems, large collectorfields on the roof and in the facadecan feed into seasonal compact heatstorage systems that retain theenergy for use in the winter months.

Active solar thermal energy systemscan also be used for cooling thebuilding. Systems will be adapted toaccommodate geographic differences.Buildings in the north of Europe willemphasise the heating aspects, whilebuildings in the south of Europe will

emphasise cooling. Buildings inCentral Europe will most likely balancethe two aspects in genericapproaches.

3.2 Solar vision for theexisting buildingstock: Active SolarRenovation

In the future, the energy-relatedrenovation of the existing building

stock will be a much bigger task thanthe construction of new buildings. Allthroughout Europe, active solarthermal energy systems offerexcellent options for carrying outenergy-related renovation of

buildings, with sustainable emission-free heating and air-conditioningsystems. Huge synergy effects can beused by combining active solarthermal systems with insulationmeasures.

Active Solar Renovation could meanthat compact facade or roof unitscontaining active solar elements willbe placed on top of existing facadesfor insulation and energy productionpurposes. Various solar facade androof modules will be available, for

example solar thermal collectors forwater or air heating, photovoltaicmodules for electricity generation, as

well as modules with transparentinsulation for directly heating thewalls.

Facade elements used for heatinsulation of existing buildings will besignificantly thinner and, at the sametime, offer greatly improved insulationcharacteristics, for example throughthe use of vacuum insulation. The

elements will be offered in a widerange of standard raster sizes and willoffer the architect all possibilities foradding full-surface solar facades tothe building. The ability to combinesolar and opaque elements with anydesired surface will extend thearchitectural design possibilities andoffer the chance of providing acomplete solar energy solution.

Other facade elements could be

directly coupled to the existing wall.The wall will be able to efficiently

absorb solar energy and direct theheat into the building in a controlledmanner. Layers within the wall will beable to regulate the heat flow into thebuilding efficiently for heating thebuilding in winter through the wall andinsulating it against external heatoutside the heating period. Buildings

could be largely heated by the wallsusing this technique.

In summer, the solar heat will be usedfor cooling the building. Cooling

machines driven by solar heat will bemuch smaller than today and highly

The Active SolarBuilding which is

100% heated andcooled by solarthermal energy willbe the building

standard for newbuildings

Active solarrenovatedbuildings will beheated and cooledby at least 50%with solar thermalenergy; activeSolar Renovationwill be the mostcost-efficient

way to renovatebuildings


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integrated. As a result, the thermalcomfort of the buildings will be muchhigher than today.

3.3 Solar vision forother applications

3.3.1 Block and district heating

In cities with dense building areas,block and district heating systemsmust significantly increase their shareof heat from solar thermal energy,biomass and geothermal. By 2030,the use of fossil fuels will be replacedby renewable heating systems inexisting block and district heating

plants, e.g. in Sweden and Poland,where they are common. In othercountries in South, Central andNorthern Europe, new block anddistrict heating systems will be built,because such systems make itpossible to heat buildings in densebuilding areas with renewable energy.Solar thermal energy is availableeverywhere and will cover a largeproportion of the energy demands ofthese block and district heatingsystems.

3.3.2 Solar assisted cooling

The world air-conditioning market isexpected to grow exponentially in thenext decades and the demand forbuilding air-conditioning will definitelyalso increase in the European andMediterranean countries. Althoughintelligent architecture willsignificantly reduce the cooling loads,and the use of environmental heat

sinks such as soil or air will save

energy and cover some of the coolingrequirements, the rising demand forcomfort and increasing summertemperatures will still cause a rapidgrowth in space cooling loads.

Solar assisted cooling (SAC) machineswill cover a large share of the coolingdemand. Due to the simultaneity ofcooling demand and solar radiation,

solar assisted cooling technology ishighly likely to cover a large share of

demand. An important reason forusing SAC is the need to avoid atotally unbalanced peak in electricityproduction during the summer period.

3.3.3 Solar thermal desalination

One of the most urgent global tasks tobe solved in the future will be tosupply people with clean drinkingwater. It is necessary to acceleratethe development of novel waterproduction systems from renewableenergy. Keeping in mind the climateprotection targets and strongenvironmental concerns, waterdesalination and water treatment

around the world will be increasinglypowered by solar, wind and other

clean natural resources in future.Often very favourable meteorologicalconditions exist for the application ofsolar thermal systems exactly in thoseareas with a high level of drinkingwater scarcity. Solar thermaldesalination and water treatmentsystems will provide excellent

possibilities to cover that need in asustainable and cost-effective way.

3.3.4 Process heat for industrialneeds and new

applications

28% of the end energy demand in theEU25 countries originates in theindustrial sector. Many industrialprocesses require heat on atemperature level below 250C. By2030, solar thermal systems will bewidely used to serve that marketsegment. Important areas for solarthermal systems exist in the food and

drink industries, the textile andchemical industries and in washingprocesses. Production halls, officebuildings, shopping centres etc willalso be heated and cooled using solarthermal energy in the future.

The availability of high temperaturecollectors will lead to the developmentof other new solar thermalapplications, e.g. solar thermal drivenrefrigerators, steam-sterilisers, solarcookers or compact solar air-conditioning systems.

Solar thermalenergy will play animportant role inall segments

where heat of upto 250 C is used


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4 Innovation and technological development

The restructuring of the heating sector

from fossil fuels to renewable andespecially solar energy generation notonly fulfils the requirements ofsustainability and ecology but is alsothe optimum direction from aneconomic point of view. By the year2030, the costs of solar thermalenergy will have been significantlyreduced by technological innovation

and industrial mass production. Onthe basis of the simultaneous increasein the cost of fossil fuel energysources, solar thermal heating andcooling will be the most cost-effective

way to generate heat and providecooling in the described marketsegments. Due to the greatadvantages of using solar thermalenergy, once it has achieved cost-

competitiveness its use will only belimited by the available space toinstall the solar thermal collectors.Some of the fields of innovation andpossibilities for cost reduction aredescribed in following.

4.1 Solar thermalcollectors

4.1.1 Integration

By 2030, in most buildings solarthermal collectors and solar electricitymodules will cover the entire south-

facing roof surface (south-facingmeans from east, through south, towest). Collectors and modulestogether with roof windows in a

unified design will share the existingsurfaces. As well as the dedicatedsolar thermal collectors, combinedsolar thermal and electricity collectors(PVT) will be available.

In addition to the roof areas, south-

facing facades will also be used asactive solar absorption surfaces. Thesolar collectors will be completelyintegrated into the building envelopecomponents. A new synergy will occurthrough compact constructiontechniques and the intelligent multi-use of construction components.

Standardisation of the installation

technology and standardisation of theinterface between the collector, theroof or facade and the rest of theinstallation will significantly reduce theinstallation time and costs. This willalso lead to improvement ofarchitectural design and therefore theacceptance and the possibilities ofusage of collectors in the roof and the

facade.

A very large innovation potentialexists in combining the functions ofthe building envelope with the heat

generation by the collector.Waterproofing, windproofing, heatinsulation of the roof and facade, andthe static loading requirements of theroof and walls have only beenintegrated into the collector design in

isolated cases up to now. Especially innew buildings, the constructionelements and the solar thermalcollectors could form a single unit inthe future. The collector can eventake over the visual presentation ofthe facade, in the sense of structureand colour.

4.1.2 Development

The strong increase of the market forsolar thermal collectors and therelated types of applications leads tothe diversification of specific collectortypes for different applications. High-

temperature collectors will bedeveloped alongside large-scalecollector modules, faade-integratedmodules and very inexpensive low

temperature collectors.

To address the segments in thetemperature range of 80C to 250C,collectors must be developed that canreach these temperatures at a highlevel of efficiency. Appropriate

technology concepts already exist, forexample flat-plate collectors withmultiple glazing and anti-reflectivecoating, stationary CPC (compoundparabolic concentrator) collectors orsmall parabolic collectors. Hightemperature collectors can also be

used for refrigeration servicesrequired in industrial processes.

Solar thermal

systems offer ahigh potential forinnovation and

cost-cutting,especially whenused as the maincomponents inheating & cooling

systems


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4.1.3 Materials

The materials and processes currentlyused in the production of solarthermal collectors do not satisfy allthe requirements of suitability for

mass production. For example, a newgeneration of plastics can bedeveloped further with respect to thenecessary mechanical, electrical andoptical characteristics. Naturalmaterials are fundamentally suitablefor heat insulation with super-

insulating characteristics, or canassume static functions. Ceramics,metal foam and other future materialspromise a high potential forinnovation in the area of collectortechnology and will promote thedevelopment of new process-oriented

heat collectors.

Significant progress in thedevelopment of functional glass

coatings has been made in recentyears, from heat-protection glazing inbuildings, to anti-reflective coatingson solar glass, which raise theefficiency of heat collectors by up to5%. Further progress is to beexpected from continuing intensiveresearch and from the latest researchresults in nanotechnology. For

example, dirt-resistant and IR-reflective layers will further increaselevels of efficiency over the entire lifespan of the product. Switchable layerswill allow the performance of the solarthermal collector to be dynamicallyadjusted to suit immediaterequirements by adjustment of thelevel of reflection. Further innovationsare seen in improved selectiveabsorber coatings regarding dirt

resistance, high-temperatureresistance, chemical resistance andperformance regulation.

4.1.4 Manufacturing

Great progress has been made inrecent years in optimising thetechnique used for joining theabsorber sheets and the absorberpipes. Further great potential forimprovement is seen in the use ofnew materials and productiontechnologies in order to reduceproduction costs, e.g. with fullthrough-flow volumetric absorbers

and frames suitable for industrialproduction.

4.2 Heat storage forsingle buildings

The fully solar heated building willusually require seasonal storage ofthe solar heat generated in thesummer months which is stored forheating demands in the wintermonths. Currently, in a well thermallyinsulated single-family house, thetoday available water storage systemsneed a volume of much more than tencubic metres to provide the necessarycapacity. By 2030, new storagetechnologies will offer a significantly

higher energy density and will reducethe required volume drastically. Thegoal is an eightfold increase in theenergy density of storage compared

to water as storage medium. Inaddition, thermal insulation of storagewill be greatly improved, e.g. usingvacuum insulation that reduces theheat losses of the storage as well asthe volume of the insulating layers.

The target is a seasonal heat storagesystem with a volume of only a fewcubic metres for single family houses.In addition to a centralised heatstorage system, decentralised storageconcepts in the form of heat-storingplastering material and storage wallswill also become available.

In order to achieve this goal, R&D inthe field of storage technology has to

have a high priority. Fundamentalresearch is required to bring about afundamental and innovativebreakthrough with regard to reachingthe target of time-indifferent, compactstorages. New approaches, likethermo-chemical (TC) storageconcepts, need to be explored.Separate paths of development arerequired in order to achieve an

evolution in new generations ofstorage concepts. Each step in theevolution from water storage, to PCM(phase change materials) storage, toTC storage will bring us closer tocompactness and time independence.

4.2.1 New materials andconcepts

The development and use of newmaterials offers great innovationpotential in storage technology.

Sorptive and thermo-chemicalprocesses achieve significantly higher

The goal is aneightfold increasein the energy

density of heatstorage by 2030


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storage densities than the waterstorage tanks used today. Newmaterials have already proven to havebetter properties than the previouslyused silica gel and zeolite types.Alongside further research into new

materials, reduction of the productioncosts also plays a significant role.

Especially in short-term storage,latent heat storage tanks using asolid-liquid phase change will offer abalance between load and source or

sink, in summer and winter. Latentheat storage systems can beintegrated into the building ortechnical systems in a variety ofdifferent ways, for example throughintegration into the building materialsand components or by introduction

into the heat transfer fluid. Bothvariations require R&D work at alllevels, from material research,

through component development, tosystem integration and actualoperation.

Another important aspect is thefurther development of insulation ofstorage systems using new materialslike vacuum insulation, superinsulation and the use of naturalmaterials with the aim to reduce heat

losses, insulation layer thickness andrecyclability.

4.2.2 Integration into thebuilding

With the introduction of seasonalstorage systems, the demands forstorage space will greatly increase.Beside the aim to increase storagedensity, this demand could be met byintegrating the storages into thetraditional construction elements of

the building. Elements such as floors,ceilings, walls and plastering willabsorb and store extra heat and thenreturn this to the building, eitherdirectly or in a controlled manner, asrequired. This direction is alreadyindicated by the use of internalplastering containing PCM at anumber of demonstration sites.

By integration of the storagefunctionality into the wall, a completedecentralised solar thermal unit withsolar collector in the facades, storagein the wall, and layers which control

the heat fluid are possible.

4.3 Heat transfer andequipment

In the future, a large proportion ofsolar thermal collectors will remainseparate from the storage mediumand will still require a heat transfercirculation loop. The development ofnew types of heat transfer media, e.g.ionic fluids, and collector loopmaterials, e.g. metallised plasticpipes, could improve system outputand reduce costs.

New pumps especially developed forthe solar heat circuit are already

reducing the electricity demand bymore than 80%. These pumps,together with additional functionality

such as measurement of the pressurewithin the loop, will become standardwithin the next years. In additionthermally driven pumps will bedeveloped.

Expansion tanks and vessels,overpressure valves, heat exchangers

and other system components will befurther integrated and developed, e.g.to resist high temperatures.

4.4 Controllers andmonitoring systems

By 2030, there will be only onecontroller for the solar thermalsystem, the backup heating and thecooling system with an integratedmonitoring functionality. This devicewill allow an immediate overview ofthe system functions and will reportfaults at an early stage. The controllerwill be self-optimising and willminimise error situations. Improvedcontrol strategies will be possible byusing weather forecasts to increasethe system output.

Development of so-called power/energy matchers or energyhubs will increase the overall systemefficiency, e.g. by matching the timingof the load to the timing of theavailability of the energy supply. Indistrict heating systems, peak loads inthe net will be avoided by allowingpower companies to adjust certain

load pattern and energy productionparameters.


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4.5 Solar district heatingsystems with andwithout very largeseasonal storages

4.5.1 Solar district heating

In dense building areas or inapplications with a mismatch betweenload and available collector mountingpossibilities, district heating systems

will be necessary in order to cover alarge share of the heat requirementsby means of solar thermal energy.These systems will be in use in allsizes, for settlements with a smallnumbers of buildings as well as forlarge residential settlements or

industry and commercial areas.

Solar block and district heatingsystems benefit in general fromeconomy-of-scale effects, as thesystems and the contracts are large.The competitiveness of solar blockand district heating systems willbenefit from the further developmentof large module collectors.

Combined solar thermal energysystems and wood fuel boilers will be

the most feasible type of block anddistrict heating systems in 2030.District heating and cooling as well ascentralised systems should bepredominant in new infrastructure

design concepts for the city oftomorrow.

4.5.2 Very large seasonal

storages

Very large seasonal storages withindistrict heating systems are necessary

in order to cover a large share of theheat demand by means of solarthermal and will be common in 2030.They benefit from the reduced surfacearea to volume ratio and thereforelower specific heat losses incomparison with small seasonalstorages in detached houses. The firstdemonstration plants of largeseasonal storages with a volume ofsome 10,000 m are installed inCentral and Northern Europe as pitstorages, ground storages and aquiferstorages. Further development isnecessary to reduce costs andincrease the efficiency.

4.6 Thermally drivencooling systems

Thermally driven cooling systems canuse any type of heat source thatprovides adequate temperatures.They are especially suitable for usewith solar thermal energy because ofthe correlation between the level ofsolar irradiation and the coolingservices required. Currently, the air-conditioning world market isdominated by decentralised room air-conditioners, e.g. split and multi-splitsystems. Moreover, these systems are

habitually less efficient than largercentralised technologies; they cause atremendous impact on the electricityrequirements in terms of energy and

power. This underlines the need forthe development of small-scale solarthermal driven cooling machines inthe range of 2-5 kW units.

Solar cooling and air-conditioning isstill in the early stages of

development and therefore offersextensive potential for innovation.Thus, there is a requirement ofextensive research into improvingstorage materials and heat transfermedia and also the furtherdevelopment of systems, to turn theminto highly compact, efficient units.One major field of research activitieshas to be the development of small-

scale systems that can coversimultaneously heating and cooling,so-called solar-combi-plus systems.The aim is to achieve commercialcompact products that can be offeredto consumers as alternatives to thesmall-scale conventional chillers.Furthermore, significant developmentwork is required in their integrationinto general building technology.

In the short term, the main tasks forresearch and development are: state-of-the-art system technology anddesign, operation and systemmonitoring as well as thedevelopment of "best practice"guidelines and generalstandardisation. In the medium term,compact combined systems forheating, cooling and process water

heating (solar-combi-plus) inresidential and small office buildingsmust be developed and the know-howmust be transferred to the plannersand installation engineers. These


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systems have to be in the form ofpackages involving a minimum ofconstruction effort in the building inorder to achieve maximum reliabilitycomfort. In the long term, units mustbe developed that are significantly

more compact, especially in the areasof lower power systems and fordecentralised use in single rooms orintegration into a facade. Facade-integrated modules will provideheating, ventilation, cooling and

dehumidification as required.

R&D effort is needed for systems withsorption processes on the low drivingtemperatures market, between 85 and110C. Further development isnecessary to lower drivingtemperatures without efficiency losses

in order to raise the heat productionefficiency of solar thermal collectors,especially flat-plate collectors. In

existing buildings and distributionsystems, cooling systems with highdriving temperatures are usuallynecessary since the installed systemsrequire low inlet temperatures.Therefore it becomes necessary to usehighly efficient solar collectors.

For multi-stage processes withmaximum efficiency, solar collectors

for high temperatures between 140and 180C have to be developed.Promising possibilities are also offeredby systems that operate as single-stage systems under low levels ofsolar irradiation and then switch to atwo-stage system when the solarirradiation is higher, or when a backupheat source such as a biomass burneris used.

The success of solar thermal assisted

cooling systems depends on theavailability of highly efficient systems

which are able to replace theelectrically driven split systemscurrently being used. Significant R&Dwork is required in order tosubstantially improve efficiency in theheat and mass transfer of the reactor,as well as in the internalinterconnection for maximisation of

heat recovery.

4.7 Solar sea waterdesalination andwater treatment

New processes are under

development to design small,decentralised, solar thermal drivensea water desalination and watertreatment systems which areespecially tuned to match the specialconditions for solar energyapplications. New processes are

necessary because the well-knownprocesses such as MED (Multi EffectDistillation) and MSF (Multi StageFlash) which are used in large-scalesea water desalination systems arenot suitable for small solar thermalsystems. The first approaches are

membrane distillation, humidification-dehumidification stills and multi-stagesolar stills.

4.8 Auxiliary systems

The remaining heat requirements ofbuildings which are 50% to 100%solar heated will be covered in a CO2-neutral manner by the use of biomassor geothermal energy, in single

buildings as well as in block anddistrict heating systems. In thesesystems, the integration of theauxiliary heat source has to beoptimised in order to guarantee

optimised efficiency of the entiresystem.

The 100% solar heated buildings andprocesses will cover the heat demandin years when average weatherconditions prevail. In order to provideheating under occasional extremeweather conditions, small backup heatsources will be installed. The briefusage periods of these devices allow a

low-cost design to be used. Therenewable backup systems could bepellet burners or biogas boilers. It isalso conceivable that, by 2030, smallchemical or hydrogen-based storagesystems will be available, which canbe loaded in summer and then usedas a backup system to cover peakloads.


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4.9 Regulations andother frameworkconditions

In order to support the furtherdevelopment and market deployment

of solar thermal energy, it isnecessary to provide, in addition tothe technology itself, the appropriateframework conditions. Among theseare methods of testing and assessing

the thermal performance, durabilityand reliability of systems andcomponents, as well as tools andeducation packages for installationengineers, planners and architects,awareness campaigns and

improvements to subsidy schemesand solar thermal ordinances.Additional effort is needed to developcontracting and financing instruments.

5 Perspective and support requirements

5.1 Cost reduction

perspective

In previous years, the price of solarthermal systems for single familyhouses, which have a market share ofmore than 80% in Europe, decreasedcontinually. In all European marketsthe trend has been equal, althoughthe system costs vary a lot accordingthe typical size, type and quality.

The learning curve of the costs for a

typical DHW system in Central Europeas shown in figure 6 indicates the pastcost development as a function oftime and increasing installed capacity.The estimates as to further costdevelopment are based on the typicallearning curve theories, depending onthe expected growth of installed

capacity.

Fig. 2: Development of specific costs and installed capacity for small solarthermal systems with forced circulation in Central Europe

Within 20 years, costs will be reducedby more than 50%. In SouthernEurope, solar thermal energy is muchcheaper due to higher solar radiationand lower costs for solar thermalsystems. Therefore, in a lot of

Southern European regions, solar heat

is already cost-competitive with heatproduced by fossil fuels. Further costreductions will depend on thedevelopment of the market and of thetechnology. Therefore marketentrance policy and R&D activities

have to be continued or strengthened.


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5.2 Economy of the solarthermal sector

By 2030, solar thermal technology willhave developed into a large economicsector, both worldwide and in Europe.There will be a strong solar thermalindustry with significant exports. Morethan 200,000 jobs will be created inthe European Union based on aannual production and installation ofsolar thermal systems with a power ofmore than 20 GWth. Many of these jobs will also be linked to theinstallation and building sector. These

jobs will therefore be spreadgeographically and between SMEs andlarge companies.

Current annual turnover in the EUmarket (2005) is over 1 billion eurosand sharply rising. Although no actualemployment statistics are available, itis estimated that the current solarthermal industry (complete supplychain) employs over 25,000 persons

(full-time equivalents).

5.3 Supportrequirements

In order to facilitate development, aconsistent and stable supportenvironment is required in the rathervolatile energy market. Supportinvolves general support for R&D

work, implementation support forsystems which pass thedemonstration stage, anddemonstration support for projectsaiming to demonstrate and learnabout the innovations.

5.3.1 Subsidies for marketdeployment

Technological development needsmarket development. Therefore,market deployment measures arenecessary, as long as solar thermalenergy is more expensive than heatfrom fossil fuels. Currently, most ofthe subsidy schemes provide grantslike in Germany or Austria, or taxreduction for the installation of a solarthermal system like in France. InSpain, solar thermal systems have tobe installed due to a solar ordinance.

The most important aspect of asuccessful subsidy scheme is that itworks continuously over a longerperiod. If there are grants, the budgethas to grow every year in order tocover the expected growth of the

market and therefore the growingnumbers of applications. Thealternative is to provide a taxreduction for solar thermal systemswhich is not limited.

5.3.2 Budget for research anddemonstration programs

In order to create an innovativeatmosphere in the solar thermal

branch, there is a need to havesufficient R&D activities in public

institutions as well as in industry, andtherefore a sufficient budget for R&D.Up to now, the public R&D budget istoo low to trigger a dynamictechnological development. In orderto achieve the goals set out in thisvision document, a strong increase ofR&D activities in the solar thermalsector in all European countries isrequired. Therefore the budget forR&D and demonstration programmeson the national and the EU level hasto be increased significantly to afigure of approximately 80 Mio Euro

annually.

5.3.3 Additional measures tocreate a solar thermalmarket

To accelerate the introduction ofproducts to the market and toproduce a further rapid spread of solarthermal energy usage, support of thefollowing measures is also necessary:

Implementation of awareness,

marketing, image-building andinformational campaigns

Training of installation engineers

Development of processes for the

comprehensive evaluation of solarthermal systems

Introduction of mechanisms forcontrolling/monitoring thefunctions of solar thermal systems

Further development of Europeanand international standards and

guidelines for solar thermalsystems and components


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6 Summary

At the beginning of 2005,approximately 10 GWth of solarthermal capacity were in operation inEurope. In the Solar Thermal Vision2030, it is believed that with the rightmix of R&D, industrial deploymentand consistent marketimplementation, the total installedcapacity could well increase to at least200 GWth by 2030. This goal isambitious but well achievable giventhe right mix of support measures and

increased R&D. By 2030, solarthermal technologies will cover up to

50% of all applications which requiretemperatures of up to 250C.

Solar thermal has a huge potential forinnovation that should now be fullyexploited. This covers the areas ofefficiency increase, as well as costreduction of solar collectors and othercomponents used in solar thermalenergy production. In particular,system technology and heat storage

systems are key elements which must

be developed further.

This vision of solar heating andcooling in 2030 refers to bothdecentralised and centralised systemsas appropriate for domestic andcommercial buildings, both newly builtand existing building stock, coolingapplications, process heat, block &district heating, and desalination.

Technical developments andrequirements are addressed, such as:

Solar absorption surfaces

Heat storage (as one of thekey research topics for thecoming decades)

Heat transfer

Cooling technologies

Large-scale solar energysystems (district, processheat/cooling, desalination)

Advanced control strategies

The learning curve for solar thermalsystems indicates the past cost

development as a function of time andincreasing installed capacity. Furtherreductions are based on the typicallearning curve theories which see afurther reduction as the marketdevelopment progresses and thetechnology matures.

In order to facilitate development, aconsistent and stable supportenvironment is required in the rather

volatile energy market. Supportinvolves general support for R&Dwork, implementation support forsystems which pass thedemonstration stage, and demon-stration support for projects aiming to

demonstrate and learn about theinnovations.

The European Solar ThermalTechnology Platform will further

follow, monitor and identify the areasin which strengthened R&D efforts willhave the highest positive impact onthe uptake of solar thermal energy.One of the goals of the ESTTP is todevelop and implement a strategicresearch agenda for the solar thermalsector, which will help the industry,the research community and publicfunding bodies to focus on high-impact topics. This will reinforce theEuropean solar thermal sector'sleading technological position.

solar thermal vision 2030 060530

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