At first glance, hydrogen is an energy superhero, solving most of the problems associated with climate change, decarbonization and the drive to eliminate greenhouse gas emissions. Popular visions of Europe 2050 or China 2060 assume the ubiquity of solar panels, windmills and other renewable technologies and the use of hydrogen as a clean fuel for heating, industry and transport. Hydrogen, together with economy of scale and advanced digital technologies, is also expected to ensure the stability of energy supplies to power systems from unstable renewable sources. Will the proper use of its potential really facilitate the necessary transformation? Or are we under the illusion of discovering a simple solution to difficult problems?
EXECUTIVE SUMMARY
- There are numerous technologies for producing hydrogen today, and the varying degrees of emissivity of these processes determine whether or not they are “green’.
- Hydrogen opens up new opportunities for the development of climate-neutral solutions in transport, industry and energy.
- It may be particularly important in the area of energy storage and stabilizing energy systems.
- Nowadays, it is nuclear technology that offers the greatest potential for the emission-free production of “green hydrogen” and, at the same time, for the optimization of its costs.
- Hydrogen optimism on the part of politicians calls for a cautious analysis of technical and economic issues, especially regarding the efficiency of fuel production processes.
- The technical solutions available today do not meet the ambitious plans, which calls into question the reality of the visions of a great hydrogen future that are being presented.
Endless source of energy
Hydrogen is the most common element in nature. In theory, it is freely available, but it does not exist in a free state on Earth; it has to be produced from other substances. Hydrogen offers the unquestionable advantage that it can be both obtained and used without any negative impact on the environment. The by-product of its production can only be pure oxygen, and the residue left over from the use of hydrogen is nothing but water. And this, using renewable energy, can be converted back into hydrogen, thus meeting the criterion of a closed loop economy.
The physical properties of hydrogen allow it to be a source of energy in a similar way to that in which we use natural gas nowadays. It can be stored, compressed, liquefied and transmitted, using appropriate installations. This inexhaustible energy source is therefore being identified as the natural successor to fossil fuels and natural gas, supporting the development of renewables and the elimination of CO2 emissions from industry and transport.
Unfortunately, hydrogen carries significant disadvantages as well. Its extremely low flash point means that under regular conditions it oxidizes at temperatures between +17 and +70 degrees Celsius. The hydrogen does this in a violent manner; it explodes, requiring extraordinary safety procedures. It is enough to recall the consequences of the ambitious use of hydrogen in aviation even before the Second World War. After another successful flight over the ocean, the transatlantic airship LZ-129 Hindenburg, a technological marvel of the time, filled with 212,000 m3 of hydrogen, burst into flames and burned to the ground on 6 May 1937 while docked at Lakehurst Airport in the US state of New Jersey. The safety systems of the world’s largest aircraft, were so unreliable that they led to the tragedy, which killed 36 people. The accident effectively halted the development of airships and other design ventures using hydrogen in aviation.
The development of technology, new materials, innovative solutions and appropriate safety procedures result in the increasing use of hydrogen by humans in a completely safe manner. Today, the largest demand for molecular hydrogen is generated by the petrochemical, chemical and energy industries. Its excellent heat-conducting and heat-storing properties are used in many thermal processes, e.g. for cooling generator windings in the conventional power industry.
There are many technologies for producing hydrogen, some of which have been known for a very long time. These include electrolysis, photo-electrolysis, steam reforming of hydrocarbons, gasification of coal, coke or biomass, thermal dissociation, biological processes (fermentation, photosynthesis), laboratory processes etc. They all share one common denominator, namely energy intensity. Thus, when considering different technologies for the commercial production and use of hydrogen, the energy balance of production, the energy source (its emissivity) and the efficiency of the overall process must be taken into account. New hydrogen research projects and technologies aim at maximizing these factors, i.e. increasing the efficiency of hydrogen extraction so that it costs as little energy and money as possible to produce 1 kg of hydrogen. If these efforts are successful, it is a prerequisite for the economic use of large-scale hydrogen.
Three colors of hydrogen
Hydrogen is a colorless and odorless gas, nevertheless the three conventional colors “green”, “grey” and “blue” are an important part of the public discussion about its use. The division relates to how the gas is obtained and, more specifically, the carbon intensity of the process.
Nowadays, the majority of hydrogen produced in the world is labelled grey. “Grey hydrogen” is most often produced by methane reforming or coal gasification, processes that use fossil fuels and have very high emissivity. The use of a raw material obtained this way, mostly in the chemical industry, is not in line with the European Green Deal.
“Blue hydrogen” is a fuel produced using non-renewable energy sources, but in the conditions of a significantly reduced carbon footprint of the process, achieved through carbon capture technology. The captured greenhouse gas is then stored (e.g. underground) or reused. The designers of the new green industrial revolution assume the possibility of a gradual transition from “grey” to “blue” hydrogen in the coming years on the way to a “green” target model. For the time being, however, this is only an assumption, as hydrogen production technologies combined with CO2 removal are at a very preliminary stage of development and are still a long way from entering the phase of becoming commercialized.
With regard to the implemented climate policy, what is most desirable is so-called “green hydrogen”, i.e. a raw material produced entirely without greenhouse gas emissions, using renewable energy. “Green” gas can be obtained by electrolysis of water, powered, for example, by a wind power plant. Such a vision is fully in line with the dream of climate neutrality, but for the time being, this technology still leaves a lot to be desired in terms of efficiency, i.e. the process performance and the price of the hydrogen produced in this manner. Not least, the production capacity for “green” hydrogen is far from sufficient.
There are various publications that distinguish the following additional “hydrogen colors” besides the three basic “hydrogen colors’: black, brown, pink, turquoise, yellow and white (here is more information on the hydrogen color spectrum), but for the purposes of this text we will stay within the framework of the tripartite division described above.
Steam instead of exhaust
Hydrogen cars do exist and do run on the roads, also in Poland. Their electric engines are powered by energy generated on an ongoing basis in a fuel cell, and the tanks hold approximately 5 kg of fuel. Such a car is filled up in a similar way to vehicles running on common LPG fuel. There are also hydrogen filling stations, although in Poland these are still only announced and planned by Orlen and PGNiG. Hydrogen motoring offers one indisputable advantage: it allows cars to be used in the same way as drivers have been used to for the last hundred years. A vehicle’s empty tank can be topped up on the spot, in a few minutes, easily and without complications. Hence the hydrogen strategy of some (not all) car companies, and the successive models of such cars on the market as well as the slow but steady growth of the service station network.
Hydrogen also seems to be the best solution for other transportation sectors. Hydrogen trucks, hydrogen locomotives and trains already exist and are in operation and more automotive, transport and rail companies are announcing their growth in this direction. Hydrogen-derived fuels such as ammonia or synthetic hydrocarbon fuels based on hydrogen and CO2 offer an alternative to liquid hydrocarbons in maritime transport and aviation.
However, the enthusiasm is not shared by everyone in the industry. The problems include the already discussed energy intensity of production by electrolysis (estimated at 55-70 kWh per kg of hydrogen), the dominance of “grey” and insufficient availability and logistics of “green” hydrogen, as well as the high cost of transport to petrol stations and, finally, the explosiveness of the gas. Given the great concern for safety, both on the part of car manufacturers and fuel distributors, the physical properties of hydrogen (that together with oxygen or air can form an explosive mixture) and the need to store it in tanks under enormous pressure, raise public concerns. Due to these reasons, the main trend in the automotive industry today is classic electrification, i.e. “plug-in” powered cars. There are also some fairly straightforward statements, such as that of Volkswagen Group boss, Herbert Diess, who said that hydrogen cars are not a solution to climate problems and that considering this alternative is a waste of time.
Cement and steel
At present, hydrogen (the “grey” one) is mainly used in the chemical industry for, among other things, the production of ammonia, hydrogen chloride and the reduction of certain metal ores. In the petrochemical industry, it is used, for instance, to produce petrol from higher boiling fractions of crude oil, and in the food industry, as the additive E949, it protects food from oxidation in sealed packaging. In challenging climate projects, which are being implemented primarily in Europe, but also in the USA and China, hydrogen is set to play a key role in transforming the entirely coal-dependent production of steel and the manufacture of cement. The key products for civilization are to be produced in emission-free processes, implemented according to the principles of a closed loop economy.
Following the trend, the steel manufacturer Arcelor Mittal has announced the implementation of two carbon-free steelmaking technological pathways. The two technologies, i.e. Smart Carbon and DRI, involve using hydrogen as a reducing agent and capturing CO2 for use in the production of chemicals and then plastics. The company estimates the cost of the multi-phase introduction of the solutions to be in the tens of billions of euros. It is no secret that the ambitious plans for a major overhaul of the steel industry cannot be realized on the basis of currently available methods (insufficient quantities of hydrogen and the required effectiveness of electrolysers), while the cost increase for carbon-free steel production is estimated at up to 80 per cent.
Cement producer Cemex, on the other hand, has announced a plan to deliver concrete with a zero carbon footprint by 2050. In 2019, in Alicante, Spain, the company successfully used “green hydrogen” for the first time as one of the fuels in its cement production process. The rapid deployment of the technology demonstrated its theoretical potential, however, insufficient solution performance and high costs still stand in the way of a total reduction in CO2 emissions.
Energy storage facilities
The fundamental problem of renewable energy sources is their unstable nature. Depending on weather conditions, they supply the system with variable amounts of energy, sometimes less and sometimes more, than consumers demand. Providing security of supply and predictability of production in a system based on renewable sources, which is what we are striving for, is therefore very difficult. Nowadays, the stability is guaranteed by fully controllable conventional sources, which still account for the vast majority of available capacity. In the coming decades, the role of stabilizers is to be taken over by intelligently managed networks and energy storage facilities.
Despite technological development, we still do not have “system batteries that are long-lasting, cost-effective and capacious enough to take in, store and dispense the energy quantities that are important for the whole energy system. We use various solutions on a smaller scale, including pumped hydroelectric energy storages, which were invented decades ago, yet still work very well. Hydrogen opens up entirely new possibilities: when solar and wind power production exceeds the system’s needs, the “surplus” can be used in electrolysis. The hydrogen thus generated can be stored and then run on combustion technologies when solar and wind power are not available.
Such storage facilities could be established at basically any renewable power plant, thus turning these sources into sustainable ones. An idea that has been much talked about recently is the use of offshore wind farms in such a way. Here, however, questions arise as to how to define this “surplus energy”, who and how will set the price of the energy produced as “surplus” that will be used to produce hydrogen. Furthermore, there is the issue of whether current electrolysis technologies are efficient and reliable enough to be interrupted at any time depending on the availability of “surplus’? Certainly, scientists and innovators are asking themselves such questions, and given the scale of investment that is anticipated in the development of this sector of the economy, it can be expected that we will soon have answers.
Similar solutions can be applied to conventional sources, which are also indirectly dependent on weather conditions. Merit-Order, which is the order in which power plants operate on the trading market, always guarantees priority to renewable sources and therefore forces a reduction in capacity or a shutdown of conventional power plants when conditions are favorable for RES. The development of hydrogen energy storage alongside gas, coal or nuclear sources would be beneficial from the point of view of the efficiency of the use of this capacity. It would also have a positive impact on the financial performance of these companies, reducing the costs of shutdowns and restarts as well as providing greater flexibility to operate in the market.
While electrolysers are becoming more common and more affordable, they still do not offer the potential to be used for large-scale hydrogen energy storage. Currently, the total worldwide capacity of these devices used to produce hydrogen is not yet staggering, but technological advances and new projects already being implemented will mean that production capacity will soon increase dramatically. In fact, there are optimistic forecasts that in the future up to 1/4 of the available energy will be related to hydrogen-based production. However, achieving this goal requires time, refinement of processes, technical solutions, regulatory frameworks, etc.
Heat and cold
Given the conditions in a country like Poland, district heating is still dependent on fossil fuels, primarily coal and, increasingly, natural gas. Alongside modern cogeneration sources, there are still old-type boiler plants running at peak demand. The potential use of hydrogen in future installations providing heat and cooling to consumers seems to be a natural direction for the development of this industry, which is in line with the concept of a closed loop economy. This gas could be used to supply heat directly or to produce synthetic fuels.
There is another aspect worth addressing here. Current hydrogen electrolysis technologies have an efficiency of about 70 %, so about 1/3 of the energy used is wasted as heat. In the reverse process, which involves producing energy from hydrogen using a fuel cell or steam turbine, the efficiency reaches about 55 %. Thus, the combined efficiency of the process of storing and releasing energy from hydrogen drops to about 30 %, in nominal conditions, unless heat recovery and utilization solutions are added, as is the case in conventional CHP. Such combined heat and power systems seem to have potential in the heat and cooling market.
Unfortunately, as it has already been mentioned, the available technologies are not yet able to fulfill expectations. The two main methods, i.e. fuel cells and gas turbines, have been known and used for decades. The trouble is that commercialized fuel cells operate on the kilowatt scale and are not suited to the needs of large-scale power generation. Higher-powered facilities are not cost- and technically competitive for the time being. The development of gas turbines is similar. There are projects enabling the combustion of natural gas blended with approx. 30% of hydrogen, as well as research projects based on hydrogen in 100%. However, we will still inevitably have to wait for their commercialization. An additional significant problem is the issue of logistics and supplying sufficient hydrogen fuel to future zero-emission CHP plants.
Hydrogen transfer and distribution
It is quite a common belief among both non-professionals and some specialists that hydrogen will be able to be transmitted and distributed via the existing gas infrastructure. This is a very attractive scenario, as it implies not only the use of gas transmission pipelines and distribution systems that have been built for decades, but also the rapid deployment of the new green fuel. Unfortunately, there are many reasons to believe that natural gas facilities cannot be used to transport hydrogen. Hydrogen easily penetrates walls and seals and is very detrimental to materials, causing corrosion and reducing their strength. Not only is there doubt among experts about the simple substitution of natural gas for hydrogen, but also about the efficiency of the method, which involves mixing a small amount of hydrogen with natural gas “at the entry” to the pipeline and recovering it “at the exit’.
There is a separate issue here, already raised in the analysis on the transitional character of natural gas. Since the gas infrastructure may not be suitable for hydrogen transmission, and the development of the gas network is accelerating rather than slowing down, is it realistic to move away from natural gas as early as 2037? Moreover, if a method of efficiently transferring hydrogen mixed with natural gas is refined, then natural gas will still need to be produced and used for something. Finally, shouldn’t the dynamics of the transmission network developed to accommodate this gas be a measure of the reality of hydrogen plans? The issues raised seem to put a big question mark over the viability of ambitious hydrogen plans on the assumed scale in the near future.
The nuclear alternative
The most effective methods of producing large quantities of cheap hydrogen, which are actually already available, are related to nuclear power. The nuclear industry as such has been clearly indicating its interest for some time in the possibility of complementing reactor power operations with hydrogen production. Their high efficiency and the heat generated offer the right potential, and the market interest in hydrogen is an opportunity for the industry to generate alternative sources of income.
The Americans have been investigating the possibility of using light-water reactors for high-temperature steam electrolysis, which would provide an efficiency advantage over the lower-temperature electrolysis used today. However, this would require increasing the heat generated at a power plant or building new ones using high-temperature reactor technology. A demonstration of such a solution is being prepared by the leading US laboratory INL (Idaho National Laboratory) together with Xcel Energy.
There is also another interesting option: the relatively simple, albeit less efficient, idea of producing hydrogen by locating “surplus” electricity production in conventional low-temperature electrolysers. The hydrogen produced in this manner, at relatively cheap cost, can be stored and converted back into energy if demand increases or used for industrial purposes. Tests of such a solution are already being carried out by Exelon Corporation at one of its US power plants. Reactor-electrolyser combinations can also be constructed based on small modular reactors (SMRs).
It does appear that, for the foreseeable future, only nuclear energy has the potential for emission-free hydrogen production on a sufficiently large scale, in technologically and financially efficient processes, yet at a reasonable price. This fact must be taken into account, as the availability of sufficient quantities of hydrogen at a competitive price is an essential condition for the success of the hydrogen revolution in all the sectors discussed.
For more information, see the World Nuclear Assotiation website.
Polish view of a hydrogen breakthrough
What should all this look like in Poland? The question has been answered by the Polish government’s project “Polish Hydrogen Strategy to 2030 with an Outline to 2040“. It assumes a dynamic development of the hydrogen market, hydrogen technologies and a gradual increase in the importance of the fuel in the European Union.
“Due to its characteristics and numerous links to a number of industries, modern hydrogen technologies can be a key factor in maintaining the competitiveness of the Polish economy. The current situation on the energy market creates an opportunity for hydrogen to play a significant role in creating a low-carbon economy. Essentially, the business and technological environment is fostering the development of hydrogen production, distribution and use in energy, industry and transport. More technologies, such as the use of hydrogen as a raw material in the production of synthetic fuels in power-to-gas, power-to-liquid and power-to-ammonia installations, could be commercialized in the near future.”
Polish Hydrogen Strategy to 2030 with an Outline to 2040
The Polish government regards hydrogen as both an opportunity and a challenge for the national economy. The document identifies six goals and 40 actions. Thus, the strategy sets forth the following:
- Implementation of hydrogen technologies in the energy sector. The pursuit of this goal indicates the need to launch a P2G (power-to-gas) installation of 1 MW class based on Polish technology (stabilization of distribution networks), support for research and development in the creation of co- and poly-generation systems (energy production) and the start of using hydrogen as an energy store.
- Use of hydrogen as an alternative fuel in transport, i.e. hydrogen buses and trains, filling stations, production of synthetic fuels based on hydrogen.
- Supporting the decarbonization of industry. In pursuit of this objective, the strategy provides support for the acquisition and application of hydrogen for petrochemical and fertilizer production processes, as well as support for so-called hydrogen valleys with a significant element of hydrogen transmission infrastructure.
- The production of hydrogen in new installations translates into launching the production of hydrogen from low-carbon sources such as electrolysis, from waste gas bio-methane and from natural gas using CO2 recovery technology, as well as through pyrolysis and other alternative technologies. It also assumes the launch of synthetic gas generation through hydrogen mechanization. The strategy also assumes the use of 2 GW of RES capacity for the production of hydrogen and synthetic fuels and to provide the conditions for the construction of hydrogen production facilities at nuclear power plants.
- Efficient and safe transmission of hydrogen. This means the gradual development of hydrogen transmission and distribution networks and the introduction of SNG produced in P2G systems into gas networks.
- Creation of a stable regulatory environment.
The Polish government expects dynamic development in all components of the hydrogen value chain and the emergence of a new hydrogen industry.
Optimism vs. realism
The main advantage of hydrogen is that it can be used in a closed circuit. To simplify things as much as possible, we can produce hydrogen fuel from water by applying energy, store or transfer the gas, and then convert it into energy and water. A process thus organized makes it possible to turn the beams of the sun and the breezes of the wind into any form of energy needed, with no greenhouse gas emissions, no waste and in an environmentally neutral way.
The hydrogen technologies are by no means new; the mechanism of operation of most of them has been known for decades or even centuries. The fact that they have not yet replaced fossil fuels is due to the technological challenges of hydrogen use, the utility limitations, the poor energy balance of the processes and the high cost of hydrogen-based solutions, the “green” ones in particular. Developing efficient solutions to produce hydrogen from renewable energy on the right scale to meet intentions is still more a future story, requiring gigantic amounts of time and work, which is unlikely an obstacle to the further reasonable development of hydrogen technologies. Some limitations are related to the physical properties of hydrogen and will always be a factor in increasing the cost of these technologies.
The ambitious plans of the architects of a new green industry, climate-neutral transport and zero-carbon energy require a fundamental overhaul of the entire energy acquisition and exploitation system. At times, it is hydrogen that is pointed out in these plans as the solution to all the difficult issues involved in the green revolution. However, it is uncertain whether this is possible, and the number of technological, economic and logistical challenges today is difficult to estimate precisely. It is worth investing in hydrogen and developing this branch of the economy based not so much on far-reaching aspirations and positive green visions of the future, but on real possibilities and solutions that are within reach in a reasonable perspective.
Sławomir Krenczyk