table 3, panel b: hydrogen for energy …...table 3, panel b: hydrogen for energy storage scope of...
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Table 3, Panel B: HYDROGEN FOR ENERGY STORAGE
Scope of discussion, background and guiding questions
November 14th and 15th, Cuernavaca, Morelos, México
Hydrogen for Energy Storage
2 U. Cano-Castillo, F. Loyola-Morales
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Content 1. INTRODUCTION ........................................................................................................................... 3
2. POWER-TO-GAS (P2G) ............................................................................................................... 3
3. STATE OF THE ART – BRIEF REVIEW ...................................................................................... 5
Production of hydrogen .................................................................................................................... 5
Hydrogen Storage.............................................................................................................................. 7
Hydrogen Use .................................................................................................................................... 8
4. EXPERIENCES ............................................................................................................................. 9
5. ADVANTAGES / DISADVANTAGES OF HYDROGEN AS AN ENERGY VECTOR ................ 12
6. KNOWLEDGE GAPS AND OTHER CHALLENGES ................................................................. 14
7. NATIONAL CONTEXT ................................................................................................................ 15
8. OTHER REFERENCES: ............................................................................................................. 15
9. QUESTIONS & ANSWERS FOR FUTURE HYDROGEN TECHNOLOGIES APPLICATIONS IN
MEXICO .............................................................................................................................................. 16
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1. INTRODUCTION Hydrogen has been considered one of the future energy vectors that may substitute oil and other
fossil fuels in our society. Just less than a month ago Bloomberg, the global finance and technology
information company, referred to hydrogen as the “secret to switching the global energy system
entirely to renewables…”1. The company also mentions that China lost $3.4 billion of revenue
because wind farms were forced to remain idle as electric lines were congested. Other countries like
Germany have suffered from the same problems as their renewable energy share increases. There
are many clear advantages when using hydrogen as an energy carrier and energy storage, for
example the fact that hydrogen can be produced out of many sources. Hydrogen does not exist free
in nature but rather forming several compounds, including water. That is, hydrogen can be produced
from many primary energy sources including renewable energy and water as feedstock. This gives
hydrogen a true sustainable character when used as an energy carrier in many applications. Its energy
content per unit mass (33.3 kWh/kg H2) is about 3 times that of most conventional fuels like gasoline
or natural gas. Once obtained from its compounds, hydrogen can be stored for very long time with
almost no energy losses depending on the storage technology. Unfortunately, hydrogen is a gas at
ambient conditions and its compression requires energy to have practical energy density storage
systems. But even at a low pressure of 200 bars, the energy density of hydrogen gas is comparable
to that of lithium-ion batteries. When needed, its energy content can be recovered by either burning
the fuel for example in a gas turbine and generate cleaner electricity or by converting hydrogen
directly into electricity in a fuel cell, an electrochemical electricity generator highly efficient.
Hydrogen could also be used for industrial applications as feedstock in refineries or in the highly
relevant fertilizer industry providing a green path for that product and for the global food industry.
Probably, for the sake of this document it is fair to say that despite some remaining technical
challenges, hydrogen is one of the most promising energy vectors for a sustainable future and as an
energy storage option, hydrogen may offer several advantages compared to more conventional
storage technologies. This is true particularly due to the possibility of storing hydrogen practically for
indefinite time and to the possibility of providing several grid services that go from renewable
integration support and grid regulation and balance, to load sharing if converted back to electricity.
Hydrogen can be used for transportation in fuel cells electric vehicles or be injected into the natural
gas pipelines adding energy content while decreasing emissions when such fuel is used.
2. POWER-TO-GAS (P2G) The Power-to-Gas or Power-to-Fuel concept refers to the possibility of storing energy when is
available and cannot be dispatched to the electrical grid and consumed by demand but transformed
into a useful fuel like hydrogen or methane for later use, either in the electrical sector itself or in
other economic activity.
1 Big Energy Backs Hydrogen Power Storage, by Anna Hirtenstein, 4 of September 2017
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The right balance between electricity supply and demand is a complex challenge, which becomes
even more puzzling when intermittent energy sources are increasing their share on the electrical
system. When using renewable sources of energy, supply is not based on demand.
Hydrogen production through electrolysis can be done at times of low demand while power can be
distributed in periods of heightened demand. This is, additional loads in the grid such as electrolyzers
allow not only a better balance when supply generates surplus electricity, but also allow the storage
of clean energy for later use.
In Germany up to 20% of wind energy in the north sea is wasted as the electrical grid is not able to
receive electricity generated if it is not needed. This issue is aggravated not only in Germany but in
many other places where renewable energy is set to increase its energy share. Mexico has set a goal
of a 35% share with renewable energy sources for the year 2024 and has been prompted to consider
the expansion of grid infrastructure by adding energy storage systems to avoid imbalances in the
grid.
Large quantities of hydrogen could be stored in underground caverns similar to those used by natural
gas (NG) suppliers as reservoirs. Moreover, hydrogen could be injected in the existing natural gas
grid, which can accept up to 5% hydrogen. Siemens has mentioned2 that the NG grid in Germany
could transport 130 terawatt-hour of electrical energy as hydrogen, representing almost 25% of
German annual power needs.
The International Energy Agency (IEA) Hydrogen Technology Collaboration Program (TCP), a
multinational coordinated hydrogen RD&D effort, dedicates its Task 38 to P2G activities including
technical, economic and regulatory aspects of hydrogen systems to examine this fuel as a key energy
carrier for a sustainable and smart energy system. Task 38 clarifies that hydrogen is generated via
electrolysis technologies with power from or independent of the grid, providing flexible energy
storage and carrier option able to defer the requirement of new lines and alleviate transmission
issues. IEA’s Hydrogen TCP lists the following applications:
transport (hydrogen for fuel cells, biofuels, synthetic methane for transport etc.)
natural gas grid (hydrogen mixed with natural gas or synthetising methane and injecting it
into the natural gas grid)
re-electrification through hydrogen turbines and stationary fuel cells
general business of merchant hydrogen for energy or industry, especially refinery, steel
industry, ammonia, etc.
ancillary services or grid services for the electricity grid, transport or distribution grid.
2 https://www.siemens.com/innovation/en/home/pictures-of-the-future/energy-and-efficiency/smart-grids-and-energy-storage-electrolyzers-energy-storage-for-the-future.html
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3. STATE OF THE ART – BRIEF REVIEW
Production of hydrogen
The main two paths in commercial use for hydrogen production are steam methane reforming (SMR)
of natural gas and electrolysis of water. In the first process, methane from NG is catalytically
converted into hydrogen. In this process, NG is exposed to steam at high temperatures at which
methane is mainly converted to CO, CO2, H2 and some unreacted methane. This product, high in
hydrogen content, is then used to produce additional hydrogen in a process called Water Shift
Reaction (WSR), where the remaining CO reacts with water molecules to generate additional
hydrogen, oxidizing CO to CO2. The hydrogen thus produced is usually purified, to get rid of unwanted
components (CO2 and remaining methane) through a Pressure Swing Adsorption (PSA) process or by
membrane separation to generate hydrogen gas of at least 99% purity3.
Any H2, CH4 and CO separated gas mixture is used in the reformer as fuel, as SMR is basically an
endothermic process, taking place at ~850°C and pressures of 20-50 bar, with catalytic conversion
which can be used for many other light hydrocarbons to produce synthesis gas. For this reason biogas
or any other synthesis gas from biological feedstock can also be used to produce hydrogen on a more
carbon neutral process compared with SMR using NG.
Heavier hydrogen containing feedstock can be used but the heavier the molecule the more difficult
the reaction is. For such heavier feedstock where energy requirement may increase, a process called
partial oxidation (PO) instead of the conventional MSR is recommended, where the hydrogen
containing feedstock is fed with oxygen and transformed into synthesis gas with a particular H2/CO
ratio prior to a Fischer-Tropsch (FT)4 process for the production of liquid hydrogen fuels. This process
is actually more suitable for biomass, carbon, and other biocompounds.
Thus, the most interesting and convenient process for the sustainable generation of hydrogen is the
electrolysis of water, where electricity from renewable sources separates water into hydrogen and
oxygen inside an electrochemical device called electrolyzer. This technology has been around for
more than seven decades, it is very efficient (>75%) and the hydrogen produced is relatively clean,
especially with modern electrolysis technologies (see below), i.e. >99.99% compared with a two-
stage MSR hydrogen (95-98%) or with modern reforming processes that include PSA (99% pure
hydrogen).
In an electrolytic process an electrolyzer or electrolytic cell, assisted by electrocatalysts, decomposes
water into its main components, i.e. hydrogen and oxygen when current flows through it. A minimum
voltage needs to be attained for the decomposition of water, which oxidizes at the anode (negative
3 Presentation: John Jechura, Hydrogen from Natural Gas via Steam Methane Reforming (SMR), Colorado School of Mines
(2015) 4 Hans Schulz, Short history and present trends of Fischer–Tropsch synthesis, Applied Catalysis A: General, Volume 186, Issues 1–2, 4 October 1999, Pages 3-12
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electrode) generating oxygen and sending protons (positive hydrogen ions) to the cathode (negative
electrode) where two protons combine with two electrons to generate pure hydrogen gas.
This process is very convenient as it can be energized with electricity from renewable sources such
as wind, hydro and solar energy. Also, electrolyzers are well fitted to operate efficiently at several
capacities which makes them very flexible and convenient for the intermittent renewable energy
sources. The most advanced technology for the electrolysis of water is the so-called polymer
electrolyte (membrane) electrolyzer (PE or PEM), which consists mainly of two electrodes cell stack,
anode and cathode, separated by a proton conducting perfluorsulfonic acid membrane that serves
as electrolyte, i.e. ion conductor. Hydrogen fuel from a PE electrolyzer is very pure and often only
needs to be dried before is stored or compressed.
In the 20th century the alkaline electrolysis technology, dominated the scene thanks to the use of
non-noble metals catalysts. Today one can buy commercial alkaline electrolyzers that can generate
pressurized hydrogen by using electrochemical methods, that is, no mechanical compression.
The need of highly alkaline electrolyte, prompt to react with CO2 present in air, represents an
operating challenge as the electrolyte reduces its ion conductivity increasing its charge resistance
and then increasing the power necessary for hydrogen production. In recent decades, this fact and
some advantages like the possibility of an acid solid thin electrolyte (more compact) promoted the
development of PE electrolysis technology.
In recent years though, the alkaline process of electrolysis has gained new attention due to the
possibility of also using alkaline membranes as electrolyte that allows the separation of both gases,
hydrogen and oxygen without any further cleaning process and the use of non-noble metals as
catalysts. In general, an alkaline media is less aggressive to many components than an acid
environment but solid alkaline electrolyzers are still under development while PE electrolyzers are
already in the market.
In recent years Electrolysis of water combining electricity and heat at high temperatures (800°C-
1,000°C, for example from solar concentrators) as energy sources has been the subject of R&D
projects as the combination of both sources of energy can yield efficiencies as high as 90%. This type
of technology makes use of ceramic electrolytes in the so-called solid oxide electrolyzer which
comprises a similar system as in a Solid Oxide Fuel Cell (SOFC). These technologies are still under
development.
The use of electrolysis for hydrogen production makes sense when any electricity surplus is used and
where the main load from the electricity source does not require electrical energy or when the grid
is not able to receive more renewable electricity. The fact that electrolysis requires electricity, makes
hydrogen production one of the grid services that hydrogen may provide by leveraging the excess
electricity generated from renewables. For this reason, electrolysis seems ideal as energy storage
from renewable sources. In such case, the energy stored takes the form of a fuel gas than can be
converted back to electricity or be used in highly energy demanding sectors like transport and
industry.
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It should be pointed out that hydrogen could be produced either in a centralized production plants
or in distributed sites before it is used, similar to electricity generation concepts. In either case, there
are advantages and challenges associated with technological and economical aspects. On the one
hand, mass production of hydrogen may reduce overall onsite production costs, while distributed
generation may reduce initial investment costs associated with transportation compared with
centralized production plants. In a recent study by the National Renewable Energy Laboratory (NREL),
it was estimated that a cost of hydrogen production of $7/kg could be competitive for transportation
applications, independent of the production path5.
Hydrogen Storage
Pressurized hydrogen is the most commercial technology used today to store hydrogen. As
mentioned above, hydrogen is hard to compress as it requires high pressures, i.e. high energy, to
store sufficient gas, but pressures of 350bar and 700bar are achieved today in vehicular applications
in fuel cells vehicles. Such pressures are enough to travel by hydrogen fuel cell cars even longer
distances than conventional gasoline vehicles, certainly much more than battery vehicles. Despite
that fact, cost of pressurized hydrogen is still high mainly due to the compression and cooling stages
energy required after hydrogen production. This energy increases even further as distribution vessels
and dispensers need to be at higher pressures before dispatch. Theoretically the energy needed to
compress hydrogen isothermally from 20 bar to 350 bar (~35 MPa) is around 1.05 kWh/kg H2 and
1.36 kWh/kg H2 from 20 bar to 700 bar (~70 MPa, the tank pressure of today’s fuel cell cars)6. A need
for cooling during fuel transfer can take some additional energy (0.15 kWh/kg H2) by pre-cooling (-
40°C) to ensure fast fill temperatures are 85°C or lower.
Advanced magnetic regenerative liquefiers may require as little energy as 7 kWh/kg LH2. For
comparison, the lower heating value (LHV) of hydrogen is 33.3 kWh/kg H2 but practical
compression energy requirement from on-site production range from approximately 5 - 20% of
LHV, while liquefaction requires 30 - 40% of LHV
Table 1. Mass Energy Content of Hydrogen compared with NG and Gasoline
Fuel Liquid Mass
Hydrogen (liquid) 1kg
Natural Gas (compressed) 2.1 kg
Gasoline (liquid) 2.8 kg
5 Early Market Hydrogen Cost Target Calculation—2015 Update, DOE Record #: 15012 Date: August 27, 2015 6 Energy requirements for hydrogen gas compression and liquefaction as related to vehicle storage needs, DOE Hydrogen
and Fuel Cells Program Record, Record #: 9013, July 7th, 2009. This estimation assumes that hydrogen is generated at 20bar.
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Linear Motor Reciprocating Compressors (LMRC) are being tested to reduce their energy
consumption during compression of hydrogen, as well as capital and maintenance costs. Other types
of compressors for hydrogen include reciprocating, conventional multistage advanced centrifugal
compressors. Air Products is commercializing hydrogen by distribution trailers at an operating
pressure of 7,500 psi (520 bar) in California and Europe.
Besides compressed hydrogen, liquefying hydrogen is one way to increase hydrogen’s energy
density, but it requires very low temperatures (cryogenic) to condense, -252.77°C. As liquid hydrogen
has a specific gravity of 70.99 g/l, its energy content can be compared with natural gas and gasoline
on a mass-based manner (related to the lower heating value), meaning liquid hydrogen is very
convenient in terms of energy content.
The storage of hydrogen in liquid form has some losses as boiling occurs at ambient conditions, which
makes storage systems complex and expensive. On the other hand pressurized hydrogen does not
present significant losses during months and even years when stored which makes it more
convenient.
Another proposed way to store hydrogen is using caverns and salt domes. The pressure needed is
usually small and according to7 the UK and the USA already use this storage system for hydrogen
which could supply grid level quantities of load following and peaking power. The Energy Technology
institute (ETI) in the UK says that for schemes operating below 40% load factor (turbine) the store
adds value reducing overall system investment.
Hydrogen Use
The energy stored as hydrogen, i.e. a chemical produced from surplus energy, can be recovered in
three general ways. The most obvious is the use of hydrogen to generate electricity in fuel cells. Fuel
cells are electrochemical devices that convert the chemical energy of hydrogen directly to electricity
without any combustion. This electricity generation is performed at high efficiencies that go from
around 55% in low temperature fuel cells, up to 85% in the less developed high temperature fuel
cells (HTFC). At higher temperature, electrochemical reactions get faster and easier, making the
reaction a more efficient process, but load following features are challenging and systems may get
very complex. Low temperature PEM Fuel Cells are the electrochemical generators more developed
as their main application in electric transportation is a very attractive market. In this sector, PEMFC
systems have seen lower costs the last few years. DOE has reported costs for PEMFC systems of
$53/kW when they are produced in volumes of 500 thousand units per annum. The economics of
PEMFC for automotive applications are sensitive to the scale of production.
Fuel cells for low temperature are well developed technologies that face costs challenges and
durability issues, but that have reached a technology readiness level of 9 as they can be obtained
7 Den Gammer, Energy Technologies Institute LLP, Hydrogen Storage and a Clean, Responsive Power System, Fuel Cell and Hydrogen Conference, Birmingham, May 2015
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commercially. Yet, fuel cell developers are not numerous8 and the technology keeps improving
making innovation a constant competition among them.
As mentioned above hydrogen can be injected in NG pipelines up to a 5% content, adding energy and
decreasing emissions when NG is burnt. Many countries, including Mexico, have well developed NG
grid systems that may receive clean hydrogen.
Finally, hydrogen produced by excess of renewable energy could also be marketed in industrial
applications giving utilities the possibility to diversify its activities beyond the energy sector, while
making its energy infrastructure more profitable. Industries that can benefit from green hydrogen
include fertilizer producers, food industry, metallurgical processes, electronics and others.
4. EXPERIENCES There are several companies and R&D organizations, including governmental institutions, that have
embarked in development and demonstration projects to generate hydrogen from renewable energy
and store it providing a series of grid services and beyond that.
A compilation of P2G projects was reported in a 2013 publication9, where tens of known projects
were identified at that time. The paper compiles projects in Germany (7), the USA (6), Canada (5),
Spain (4) and the United Kingdom (4). In this review paper projects from other European countries,
Argentina and Japan are also mentioned. The main conclusions of this review paper were the need
of continuous long-term operation, system configuration and overall performance improvements.
Among improvements the efficiency, reliability, lifetime, maintenance, costs of components were
mentioned as relevant. Dealing with fluctuating power sources and reduction of ancillary
components were also mentioned as opportunities for improving systems.
The following is an adapted table published in September 2017 by Bloomberg, sourced through its
industry research branch Bloomberg New Energy Finance (BNEF), of some projects in the order of 1
MW or beyond in several European countries. In the same table, 3 more projects were added by the
author of this report, including one in Fukushima Japan that may become the largest P2G plant in the
world.
The Falkenhagen plant listed above started in August 2013 by Uniper and converts excess wind power
into hydrogen. The gas is then fed into a plant that combines the gas with CO2 to produce methane,
which is transported and stored in the existing pipelines. The convenience of using green hydrogen
in methanisation processes is the improvement of CO2 conversion from 60% to 95% and reducing
GHG emissions according to Proton Onsite, a company that offers PEM Electrolyzer technology up to
1MW10.
8 Incluyendo al INEEL el cual ha desarrollado su propia tecnología de PEMFC 9 Gerda Gahleitner, Hydrogen from renewable electricity: An international review of power-to-gas pilot plants for stationary applications, International Journal of Hydrogen Energy 38, (2013), pp. 2039-2061 10 https://vimeo.com/185368302 (video )
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Table 2. Grid Related recent projects of Hydrogen Applications
Project Company Country MW
WindGas Hamburg Uniper Germany 1.7
WindGas Falkenhagen Uniper Germany 2
ITHER Foundation for the Development
of New Technologies in Aragon
Spain 0.7
INGRID McPhy Energy & 6 others Italy 1.2
Werden-Kessin WIND Projekt Ingenieur Germany 1
Fukushima (begin to operate
in 2021)
Toshiba Corp. & utility Tohoku
Electric Power Co.
Japan 10
EnergyStock Zuidwending EnergyStock (Electrolyzer from
ITM Power)
Netherlands 1.1
Orkney Tidal-powered
220kgH2/day generation and
compression (in preparation
for the Surf’n’Turf project,
see text)
European Marine Energy Centre
(EMEC) and ITM Power
UK 0.5
Energiepark Mainz Siemens and Mainz Germany 6
On the 19th of September this year, ITM Power announced the sale of a 1.1MW rapid-response PEM
electrolyzer to EnergyStock, a subsidiary of Gasunie, a gas transmission network operator from the
Netherlands11. Such an electrolyzer will be situated at EnergyStock’s Zuidwending salt cavern storage
facility in the northern part of that country. The hydrogen will be utilized in EnergyStock’s systems,
or distributed by tube trailers to future hydrogen refueling stations. According to ITM Power, P2G is
the lowest cost long duration, energy storage technology known. With this project, ITM P2G Energy
Storage exploits the virtues of an existing asset (the gas grid) to decarbonise both electricity and gas
networks.
Also in September 2017, ITM Power revealed the world’s first tidal-powered hydrogen generated at
Orkney, Scotland with the European Marine Energy Centre (EMEC). Hydrogen was generated using
electricity from tidal energy. ITM Power supplied the PEM electrolyzer, which according to their
11 http://www.itm-power.com/news-item/sale-of-1-1mw-power-to-gas-plant-to-energystock
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website is a rapid response system with self-pressurisation up to 20 bar. EMEC uses a series of
prototype tidal energy converters – Scotrenewables’ SR2000 and Tocardo’s TFS and T2 turbine.
The Surf’n’Turf project being led by Community Energy Scotland in partnership with Orkney Islands
Council, EMEC, Eday Renewable Energy and ITM Power, will be using the electrolyzer acquired by
EMEC. The project plans to use electricity from EMEC’s test site and from a 900kW Enercon wind
turbine from Eday community. Once generated, hydrogen will be transported to Kirkwall, to operate
a fuel cell installed on the pier as auxiliary power for ferries when tied up overnight.
Although not for grid services, back in 2003 INEEL (formerly IIE) integrated a hydrogen production
system in Mexico using solar energy. The system was simplified to avoid the use of expensive
components. Such simplification was achieved by direct coupling of an electrolyzer with a
photovoltaic system designed to operate near its maximum power point at the voltage needed for
hydrogen generation. A commercial system with a capacity of 1m3 of H2 per hour by Proton was
used12. Such configuration avoided the less developed power conditioning from the PV system for
connection to power the electrolyzer. Also, the adaptability of the electrochemical hydrogen
generator to the fluctuating energy source was identified.
As mentioned above, hydrogen produced from renewables could be used in combined cycle gas
turbines (CCGT), reducing the GHG emissions from conventional CCGT operating on NG. Siemens
anticipates that by 2018, turbines that can burn hydrogen will be available13. An estimation of 50%
energy losses are expected on the way from wind energy to electricity from a turbine (including
electrolysis) but the wind turbines will not need to be turned off due to overcapacity and GHG
emissions will be avoided to generate electricity.
This same company has its own electrolysis technology based on the PEM type of hydrogen
generator, which according to the company it responds within milliseconds to intermittency from
renewable energy even under three times its nominal power rating for a short while. This technology
is at its prototype stage with a nominal power rating of ten kilowatts (kW) reaching 300 kW when
needed. From this development, Siemens was planning in 2015 to deploy three electrolysis systems
of a combined output of 6MW. This project would enter service within a research project in Mainz,
Germany. The hydrogen produced from renewable wind energy, will be integrated into the gas power
grid as energy storage option or supplied to a filling station for fuel cell vehicles.
Recent studies at INEEL explored the effect on electrical grid feeders in Mexico City, of the
introduction of electric vehicles, both lug-in and hydrogen vehicles. These studies included the
possibility of connecting 30 electrolyzers for hydrogen generation to produce this fuel at low demand
hours, i.e. between 9pm and 6am, with no impact on the feeder. The results showed that even more
electrolyzers could be connected for a distributed generation of hydrogen. The studies also included
the potential benefit of implementing V2G (Vehicle-to-Grid) technology. Although the study assumed
12 Direct coupling of a solar-hydrogen system in Mexico, L.G. Arriaga et al., International Journal of Hydrogen Energy 32,
issue 13 (September 2007), 2247 – 2252 13 https://www.siemens.com/innovation/en/home/pictures-of-the-future/energy-and-efficiency/smart-grids-and-energy-storage-electrolyzers-energy-storage-for-the-future.html
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battery vehicles, hydrogen fuel cells electric vehicles can also be considered. This study showed the
V2G benefits satisfying demand at peak hours, helping to reduce power losses and assisting in
improving voltage profile14.
Mainz part of the province of Rhineland-Palatinate, seeks eliminating fossil fuels from electricity
production by 2030. The project, Energiepark Mainz, uses Siemens Silyzer 200 PEM electrolysis
systems that operates with a conversion efficiency of 65-70%15. The website of the project says that
the hydrogen production system is enough to compensate capacity shortages in the distribution grid
and provide stabilization to the grid. The same site mentions the testing of commercial operation
stage for 2017.
This very same year (2017) the Hydrogen Council (HC), a consortium of global companies from major
energy and industrial sectors, was formed to position hydrogen fuel among the key solutions of the
energy transition. In this council the CEO-level group is made up of 18 leading energy, transport and
industry multinationals like Air Liquide, Alstom, Anglo American, Audi, BMW Group, Daimler, ENGIE,
General Motors, Hyundai, Iwatani, Kawasaki, Plastic Omnium, Shell, Statoil, The Linde Group, Total
and Toyota. In that spirit, the Council does the following recommendations “to unlock the
contribution of hydrogen to the energy transition”16:
Provide long-term and stable policy frameworks to guide the energy transition in all sectors
(energy, transport, industry, and residential). They offered their expertise on the feasibility
of decarbonization solutions in each sector.
Develop coordination and incentive policies to encourage early deployment of hydrogen
solutions and sufficient private-sector investments. These policies should complement sector
policies and provide tools to capture the benefits of hydrogen.
Facilitate harmonization of industry standards across regions and sectors to enable hydrogen
technologies and take advantage of scale effects and decrease costs.
5. ADVANTAGES / DISADVANTAGES OF HYDROGEN AS AN ENERGY
VECTOR
There are many advantages for the use of hydrogen from the energy point of view:
It has the highest energy content per mass unit of any known fuel and even @ 200bar its
energy density compares with Li ion batteries
It can be produced from several feedstock materials including biomaterials, water, and even
fossil sources (if needed), in which case some CO2 will be associated or captured
Its production, mainly through electrolysis, is compatible with renewable energy sources and
it can lower associated intermittent power disruptions
14 Khan, et al., V2G study for electric grid reinforcement in a commercial feeder in Mexico City, ROPEC 2017, IEEE S.
Centro Occidente 15 http://www.energiepark-mainz.de/en/ 16 http://hydrogencouncil.com/our-mission/
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Its transport and distribution use technologies that are well known and even represent a
complement for energy distribution
When electrolysis is the preferred method of its production, its operation is highly flexible as
its efficiency remains relatively high at partial capacity. Electrolysis tolerates fluctuating
power profiles
Electrolyzers have high response rate in the order of miliseconds
Its energy conversion during production is reasonably high, i.e. 70% or higher
Current Electrolysis technologies are self-pressurized and generate hydrogen suitable for
energy storage, transportation applications and for blending the fuel with natural gas to
reduce GHG emissions
It can be stored as a pressurized gas for months and even for longer times, possibly
indefinitely. Making it suitable for seasonal energy harvesting and use.
Once hydrogen is pressurized, its energy storage capacity is determined only by the size of
its vessel
It can be used for power generation in gas turbines and fuel cells, and for transport systems
in fuel cell electrical vehicles
When hydrogen is stored in a fuel cell vehicle, it can provide grid services by V2G technology
Most technologies to exploit the benefits of hydrogen have been developed (some of them
decades ago) and most are commercially available now
Fig. 1 Schematics of Hydrogen for energy storage: production, grid-connected uses and other
applications
The remaining challenges for the ample use of hydrogen as a fuel and as an energy storage means
are:
Hydrogen is an added value product as it is not free in nature
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Its energy capacity depends on the physical conditions, i.e. pressure and temperature,
therefore commercial technologies need energy to store it
Hydrogen compression and transport are costly, making its related infrastructure costs
relatively high
In the cost evaluation of hydrogen options, the reduction in greenhouse gases (GHG) is not
considered as a positive economic impact. Although other technologies generate GHG and other
pollutants in their life cycle, they are not evaluated in economic terms for the damage they bring to
societies, which can be in the order of $220/ton17 according to a recent study published in the
Stanford University News Service in 2017.
6. KNOWLEDGE GAPS AND OTHER CHALLENGES Although several ongoing projects are in the search for making hydrogen a feasible option as an
energy storage and energy vector, in particular for the electrical grid, none of them is being
developed under market conditions. This is understandable as they are emerging technologies that
need testing and evaluated before they are inserted in the market.
As mentioned on the advantages section, many hydrogen technologies for its production, storage
and final use, have been developed and are commercially available today, despite its high costs in
some cases. This means that many hydrogen technologies have a TRL18 of 9. For this reason one of
the main challenges for hydrogen technologies rely on the reduction of costs, by substitution of
components and reduction of manufacturing costs. Although this is true, there is space for
improvement of technologies performance, which in turn shall decrease costs.
On the application side related to grid services, interfaces such as power electronics need to be
developed under more standardized configurations to ensure compatibility among equipment
components integrated into hydrogen energy systems. This includes rectifiers, inverters, d.c./d.c.
regulators, control systems, etc.
A lot of experience needs to build up in order to guarantee continuity of performance operation of
hydrogen systems and confirm design and technical specifications.
Economic models and business cases need to be developed to initiate an energy market based on
hydrogen energy storage.
17 Compared with the $37/ton of CO2 cost from US Government estimation and that Mexico, USA and Germany use for its planning 18 Technology Readiness Level o Nivel de Prontitud Tecnológica basado en conceptos de la NASA
Hydrogen for Energy Storage
15 U. Cano-Castillo, F. Loyola-Morales
INEEL noviembre 2017
7. NATIONAL CONTEXT Since 1999, Mexico has a professional association dedicated to the promotion and development of
technologies associated with hydrogen as a fuel. This association, Sociedad Mexicana del Hidrógeno19
(SMH), organizes an annual Technical Congress where activities of members from several R&DT
institutions in the country present their progress. The event also brings international specialists as
main invitees and offers technical courses for students and professionals interested in hydrogen as
an energy vector.
In Mexico, the experience with hydrogen production from electrolysis has been limited with SMH
members as main active players. The Instituto Nacional de Electricidad y Energías Limpias (INEEL) in
the state of Morelos, integrated a solar hydrogen system using renewable energy sources to generate
hydrogen through electrolysis in 2003. INEEL has developed its own PEMFC and PE Electrolyzer
technologies within the Renewable Energy Department of INEEL. Other institutions have followed in
recent years with small hybrid systems integrated with commercial components. Institutions with
interest in hydrogen generation from renewable energy include the Instituto Politécnico Nacional
(IPN) in Mexico City and the University of Quintana Roo (U.QRoo) in Chetumal and the Instituto
Tecnológico de Cancún (ITC) in same state.
The SMH has made several efforts to develop a National Hydrogen Plan and bring it to the head of
the energy sector with little success. The Mexican Council for Science and Technology (CONACYT or
Consejo Nacional de Ciencia y Tecnología) supports several projects on hydrogen technologies, from
its production to its final use, but there is not a guide nor a coordinating effort as to the type of
projects, challenges and opportunities in the country.
Although Mexico participates in some TCP’s of the IEA, such as Fuel Cells, Wind, PV and Solar
concentration, among others, to the author’s knowledge, this country does not participate in the
hydrogen TCP. Mexico is now an official member of the IEA but its participation in TCP’s requires
funding for its membership, meeting attendance and mainly for sustaining substantial activities in
the topic of interest. The benefits of such membership are very relevant.
8. OTHER REFERENCES: Siemens: https://www.siemens.com/innovation/en/home/pictures-of-the-future/energy-and-
efficiency/smart-grids-and-energy-storage-electrolyzers-energy-storage-for-the-future.html
TÜV SÜD: https://www.netinform.net/H2/Wegweiser/Guide2.aspx?Ebene1_ID=48
Shell: http://www.shell.com/energy-and-innovation/the-energy-future/future-
transport/hydrogen.html
Alternative Fuels Data Center (USA):
http://www.afdc.energy.gov/vehicles/emissions_hydrogen.html
Sustainable Transportation (USA): http://www.energy.gov/eere/fuelcells/fuel-cell-technologies-
office
19 Mexican Hydrogen Society, see http://hidrogeno.org.mx/
Hydrogen for Energy Storage
16 U. Cano-Castillo, F. Loyola-Morales
INEEL noviembre 2017
International Partnership for Advancing the Hydrogen Economy (INT’L):
http://www.iphe.net/partners/japan.html
Partnership for Advancing the Transition to Hydrogen (Int’l): http://www.hpath.org/
We-net (Japan): http://www.enaa.or.jp/WE-NET/contents_e.html
H2 Program Japan (H2 y FC): http://www.fccj.jp/eng/index.html
Hydrogen TCP International Energy Agency (IEA): https://www.iea.org/tcp/renewables/hydrogen/
and http://ieahia.org/
Technology Collaboration Programme on Advanced Fuel Cells (IEA): http://www.ieafuelcell.com/
German Hydrogen and Fuel Cells Association: http://www.dwv-info.de/expert-commission-
performing-energy/politics/european-law/?lang=en
National Renewable Energy Laboratory (USA): http://www.nrel.gov/hydrogen/
Toyota: http://www.toyota-global.com/innovation/environmental_technology/fuelcell_vehicle/
Hyundai: https://www.hyundaiusa.com/tucsonfuelcell/index.aspx
Honda: http://world.honda.com/FuelCell/
BMW: http://www.bmwblog.com/2016/03/28/bmws-hydrogen-car-getting-closer-becoming-
reality/
Los Alamos National Laboratory (USA): http://periodic.lanl.gov/1.shtml
Fuel Cell and Hydrogen Energy Association: http://www.fchea.org/
Canadian hydrogen and fuel cell association: http://www.chfca.ca/
Codes and Standards:
http://www.fuelcellstandards.com/Hydrogen%20Matrix.pdf
http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_tc_browse.htm?commid=54560
http://www.fchea.org/regulations-codes-standards/
http://energy.gov/eere/fuelcells/articles/10-questions-regarding-sae-hydrogen-fueling-standards
9. QUESTIONS & ANSWERS FOR FUTURE HYDROGEN TECHNOLOGIES
APPLICATIONS IN MEXICO During the Workshop several questions will be made to reflect and discuss on the opportunities for
the Mexican electrical grid and electricity market, as well as general opportunities for the energy
sector when using hydrogen. Among the questions that will be raised during the workshop, the
following could be considered:
What benefits can hydrogen bring to the Mexican electricity infrastructure?
What opportunities does hydrogen represent for the Mexican energy sector?
What are the knowledge gaps for Mexico concerning hydrogen technologies developed in
other regions?