The report elaborates on hydrogen as a potential clean energy source, while explaining the differences between “green hydrogen” and hydrogen produced from fossil fuels. The 41-page document could help policymakers understand the real potential of green hydrogen and avoid the marketing trap behind hydrogen campaigns conducted by fossil fuels companies. Additionally, the report discusses the most promising applications of green hydrogen.

Although hydrogen has green energy potential, today´s reality is the opposite of that. The report mentions that today, most hydrogen production does not occur through an environmentally friendly process and significantly contributes to climate change. Oil and gas companies are the biggest hydrogen producers: the hydrogen is obtained through steam methane reforming (SMR) of fossil gas, which is a pollution-intensive process. 99.8 percent of global hydrogen production is not green and generates an enormous amount of air pollution. (According to the International Energy Agency (IEA), annual hydrogen demand worldwide is more than the primary energy supply of the entire nation of Germany.) Additionally, SMR emits harmful pollutants such as nitrogen oxides, carbon monoxide, and volatile organic compounds. Local communities near oil refineries are mostly affected by these pollutants.

The fossil fuel industry is not only the producer but is also the primary consumer of hydrogen. (Approximately 60 percent of domestic hydrogen demand comes from crude oil refineries.) Here, hydrogen is used to lower the sulfur content of diesel. The second-largest hydrogen consumer is the agriculture industry (about 30 percent), where hydrogen is used as a feedstock for chemical fertilizers. The remaining 10 percent of hydrogen is used for other chemical processes such as methanol production.

Fossil fuel companies have joined forces to gain policy support for hydrogen production. They promote it not only as a green solution for home applications (heating, cooking) but also as a solution for transportation. However, it should be noted that these companies continually use the same hydrogen production process, which is far from green.

Hydrogen can become a decarbonization tool if policymakers understand what green hydrogen is. The key question is: how is hydrogen made? Today, the only green method of hydrogen production without negatively affecting the environment is by electrolysis powered by fully renewable electrical energy. In this process, hydrogen is split from water molecules. The IEA defines “green hydrogen” as hydrogen produced by using electricity generated from renewable energy sources.

Using renewable energy is essential because electrolysis is a highly energy-intensive process and using energy from any other available source on the grid will cause even more CO₂ emissions than the SMR hydrogen production process.

The report further warns policymakers about hydrogen produced from biomethane or biomass, which is also presented as a green approach. Although biomass is meant to be generated from organic waste, the reality is quite different. (In fact, this method of production provides just a minor part of the required biomass.) Usually, biomass is produced from timber or crops grown for the purpose of becoming an energy source. Biomass is not a carbon-neutral energy source and contributes significantly to greenhouse gas emissions.

The diagram below illustrates carbon emissions caused by different hydrogen production approaches.

Production Capacity of Green Hydrogen

Currently, Europe is a leader in deploying the technology to produce green hydrogen. The European Commission has set a target for deploying renewable hydrogen electrolyzers in the amount of 6 GW by 2024 and 40 GW by 2030. This will require a massive scale of manufacturing capacity, and Europe must double its green hydrogen projects to hit the target. The final goal is to halve the costs of electrolyzers by 2030, as they are currently extremely high.

The first limitation of green hydrogen is energy inefficiency because of the process of converting electrical energy into hydrogen. Electrolysis powered by renewable energy results in significant energy losses—between 20–40 percent. Thus, hydrogen is a more expensive energy source than renewable electricity. Additionally, devices powered by hydrogen have less efficiency than electrical devices. There are also difficulties with storing and transporting the hydrogen, as well as environmental challenges such as water needed for hydrogen production.

Hydrogen also generates health-harming pollution from combustion. Although hydrogen

fuel cells only emit water vapor, there are many potential applications where hydrogen involves combustion instead of fuel cells. The harmful pollutants are oxides of nitrogen (NO_x), which can damage the heart and respiratory functions of people.

The report discusses if hydrogen is an effective solution in different applications such as in homes (heating, cooking), industry, and transportation.

Analysis shows that hydrogen cannot be the first choice in homes for powering household appliances. There is a safety risk of hydrogen leaking—and hydrogen is also a greenhouse gas. The more efficient solution in homes is to use electric appliances powered directly by renewable energy.

In the transportation sector, battery-operated electric vehicles (EVs) are more energy efficient and affordable than hydrogen vehicles. This is why Sasan Saadat, coauthor of the report, said: “Hydrogen isn’t the silver bullet it’s marketed to be. Worse, the deluge of hydrogen hype from fossil fuel companies threatens to delay the clean energy transition by siphoning resources away from solutions like electric appliances and vehicles. In the future, green hydrogen may help us carry renewable energy into the toughest corners of the energy system, but it’s no substitute for rapidly electrifying the bulk of our economy today.”

Nevertheless, green hydrogen can be a solution in decarbonized sectors where electrification is not possible.

When hydrogen applications are discussed, they should be divided into three groups:

• Sectors where green hydrogen represents an effective solution
• Sectors where green hydrogen should be explored with caution
• Sectors where green hydrogen is not an effective solution

As previously explained, fossil fuel industries produce large amounts of hydrogen, which significantly affects the climate. This is probably the most important sector where green hydrogen can be the solution to reducing emissions. Additionally, green hydrogen does not require new technologies for its use. The hydrogen can be transported by using a dedicated pipeline and can be stored in the currently used infrastructure. It is important to note that this potential of green hydrogen as a displacement for fossil hydrogen should not be used as an excuse for the expansion of refineries and chemical fertilizer plants.

There are many sectors where green hydrogen can be used as a decarbonization tool but because of some drawbacks or lack of technology it needs to be explored with caution. The first potential sector is maritime shipping because about 3 percent of total greenhouse gas emissions and 15 percent of total sulfur oxides and nitrogen oxides pollution are generated from this sector. Batteries are still not a solution for long-distance maritime transport because of limited capacity and the need for recharging. Green hydrogen is identified as a potential solution for long-distance voyages because of its simpler storage and higher energy density. A greener approach is to use hydrogen in fuel cells, but this technology still needs to be improved.

The aviation sector also significantly contributes to pollution, at about 2 percent of global CO₂ emissions. As with the maritime sector, there are limitations to using batteries in this application. There is a proposal to use green hydrogen or its derivate hydrogen-based liquid fuel to decarbonize this sector. A few pilot projects are available, but the technology has yet to be improved.

High-heat industrial processes, such as steel production where electric decarbonization is not an option, can use green hydrogen as a solution. This would be an alternative to cooking coal in the iron-ore reduction process or in processes that require high-temperature heat. However, this industry needs a low-cost heating solution—a challenge for green hydrogen.

Green hydrogen has good potential for use in long-term storage of renewable electricity together with fuel cells. This can be a cost-effective solution for decarbonizing the electric grid, even for long periods with very low energy loss. Fuel cells can be used as a reversible storage solution that can convert green hydrogen into electricity when it is needed.

Fuel cell technology has high efficiency and is already available. However, fuel cells have a low energy density compared to combustion turbines. They are still effective for smaller power plants around 60 MW. For higher scales, fuel cell technology should be improved to be cost-effective.

Many will agree that switching from fossil fuels to renewable energy is the most effective way to reduce emissions. In sectors where electricity from renewable energy cannot be used directly, green hydrogen can be an effective solution.