Table 3, Panel B: HYDROGEN FOR ENERGY STORAGE Scope of discussion, background and guiding questions

November 14th and 15th, Cuernavaca, Morelos, México

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Hydrogen for Energy Storage

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

2 U. Cano-Castillo, F. Loyola-Morales

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Hydrogen for Energy Storage 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 3 U. Cano-Castillo, F. Loyola-Morales

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Hydrogen for Energy Storage 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 4 U. Cano-Castillo, F. Loyola-Morales

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Hydrogen for Energy Storage 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 5 U. Cano-Castillo, F. Loyola-Morales

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Hydrogen for Energy Storage 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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Hydrogen for Energy Storage 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 6 1.36 kWh/kg H2 from 20 bar to 700 bar (~70 MPa, the tank pressure of today’s fuel cell cars) . 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. 7 U. Cano-Castillo, F. Loyola-Morales

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Hydrogen for Energy Storage 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 8 U. Cano-Castillo, F. Loyola-Morales

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Hydrogen for Energy Storage 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 ) 9 U. Cano-Castillo, F. Loyola-Morales

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Hydrogen for Energy Storage 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 Spain 0.7 of New Technologies in Aragon

INGRID McPhy Energy & 6 others Italy 1.2

Werden-Kessin WIND Projekt Ingenieur Germany 1

Fukushima (begin to operate Toshiba Corp. & utility Tohoku Japan 10 in 2021) Electric Power Co.

EnergyStock Zuidwending EnergyStock (Electrolyzer from Netherlands 1.1 ITM Power)

Orkney Tidal-powered European Marine Energy Centre UK 0.5

220kgH2/day generation and (EMEC) and ITM Power compression (in preparation for the Surf’n’Turf project, see text)

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 10 U. Cano-Castillo, F. Loyola-Morales

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Hydrogen for Energy Storage 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 3 hydrogen generation. A commercial system with a capacity of 1m 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 11 U. Cano-Castillo, F. Loyola-Morales

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Hydrogen for Energy Storage 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/ 12 U. Cano-Castillo, F. Loyola-Morales

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Hydrogen for Energy Storage  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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Hydrogen for Energy Storage  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 14 U. Cano-Castillo, F. Loyola-Morales

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Hydrogen for Energy Storage 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/ 15 U. Cano-Castillo, F. Loyola-Morales

INEEL noviembre 2017

Hydrogen for Energy Storage 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?

16 U. Cano-Castillo, F. Loyola-Morales