Hydrogen Horizons: Unlocking the Potential of Green Hydrogen – Insights from Danfoss on Production, Use, and Efficiency in an exclusive Q&A with Hydrogen Central
In a world striving to reduce dependence on fossil fuels, hydrogen is emerging as a key player in the transition to clean energy. However, its production, application, and efficiency raise important questions. In this exclusive Q&A, Hydrogen Central engages with Danfoss to explore the potential of hydrogen, how it can be most effectively produced and utilized, and where its use may not be ideal. From green and blue hydrogen to its role in industries that are difficult to electrify, Danfoss provides valuable insights into the evolving hydrogen landscape and its future in the energy mix.
- Q: Why is hydrogen needed and what is the most efficient way it can be produced?
A: Hydrogen is often seen as a miracle fuel and will play a critical role in the transition away from fossil fuels. But it must be used in addition to electrification and energy efficiency improvements. Step one is to electrify as much as we can with renewable energy sources and eliminate energy waste. Electricity should be used wherever possible. The most cost-efficient strategy is to first implement all possible electrification and energy efficiency measures, then meet the remaining demand with hydrogen.
All hydrogen is not created equal. There are many ways to produce hydrogen. Let’s have a look at the two most well-known types of clean hydrogen, green and blue.
Green hydrogen is made through electrolysis where electricity splits water into hydrogen and oxygen. In order for hydrogen to be called “green”, the power supply must stem from renewable sources. Green hydrogen can have a carbon footprint from 0.5 to 6.6 kg of CO2e per kg of H2 and is one of the most promising options to supply low-emission hydrogen in the future.
Blue hydrogen is produced with fossil fuels such as natural gas or coal. Usually, blue hydrogen is produced through processes called steam methane reforming or coal gasification. Carbon emissions are captured and stored. At best, 85-95% of the carbon can be captured, which means that 5-15% is still emitted. Blue hydrogen is considered a low emission hydrogen, but emitting 1.5-6.3 kg of CO2e per kg H2, it is not the cleanest option.
- Q: How can hydrogen be used most effectively?
A: The best use of hydrogen is to decarbonize industries which are difficult to electrify directly, such as aviation and steel, fertilizer and cement production, which emit large quantities of carbon. Long range aircrafts cannot fly on battery power and many heavy industries employ high temperature processes where hydrogen can replace oil, natural gas and coal. Green hydrogen will be produced when large amounts of renewable electricity is available at low cost. The hydrogen can be stored and converted to other fuels like methanol, ammonia and sustainable aviation fuels.
- Q: In what settings is the use of hydrogen not recommended?
A: When hydrogen power is used, about one third of the electric energy is converted to heat and released into the atmosphere, and two thirds of the energy is actually turned into hydrogen. This is why direct electrification usually is more efficient than indirect electrification using hydrogen. Hydrogen used for heating of homes is one of the least efficient uses. Electric heat pumps are much more efficient. Danfoss recently conducted a study in the United Kingdom, which showed that replacing natural gas with green hydrogen for heating requires the energy of six times more wind turbines compared to using electric heat pumps or using surplus heat from industrial facilities to heat homes as part of a district energy system.
Using hydrogen to power personal cars and light trucks is also inefficient. Only 15% of the energy produced will be used to power the car. The remaining 85% will be lost as heat during the electrolysis, compression and transport of the hydrogen and conversion of the hydrogen back to electricity. Electric cars use approximately 80% of the energy to power the car and the cost of electric vehicles is decreasing every day.
- Can hydrogen be used for other forms of transportation?
A: Hydrogen can work well in heavy transport, where it is difficult or very expensive to electrify directly. In many places in North America, it is very expensive to go from diesel-powered locomotives to electric trains. Battery-powered passenger trains are available but there are no heavy goods trains powered by batteries only. However, trains with electrical drive systems powered by hydrogen fuel cells and batteries are good solutions to decarbonize the train transport sector.
There is still debate about the use of hydrogen for long haul trucking. Hydrogen-powered long haul heavy trucking will coexist with electric trucks for light/medium duty.
- How can the efficiency of green hydrogen electrolysis be improved?
A: The electrolyzer itself is the element in the chain where most of the electricity is wasted as surplus heat. All electrolyzer manufacturers are developing new designs with improved efficiency. Surplus heat is also generated in electric power conversion. This good news is that there are new AC to DC power converter technologies available today where the system efficiency is at least one percent better than traditional converters. One percent efficiency improvement will make a big impact on the operating costs of a hydrogen plant over a 15-20 year lifetime.
- Q: What is the safest and most effective way to transport and store large amounts of hydrogen?
A: Hydrogen is very expensive to transport in tube trailers and pressurized tanks on trucks. This puts a natural limit to the geographic range hydrogen can be transported economically. But hydrogen is almost as easy to transport in pipelines as natural gas. Hydrogen can also be stored in large amounts in underground caverns, just like natural gas. Having a hydrogen storage system enables the transportation of hydrogen over long distances between large producers and large consumers. It is typically less expensive to transport hydrogen in pipelines over a distance over 500 miles than to transfer the same amount of energy as electricity.
- Q: Can hydrogen be transported internationally by ship?
A: Hydrogen has a low energy density which makes it difficult to transport in tankers the same way as liquid natural gas (LNG). There are many projects in the pipeline to export green hydrogen by ship, but the hydrogen must be converted to ammonia or methanol before shipping. There are ambitious plans in Atlantic Canada to export large amounts of green ammonia to Europe, with an agreement in place between Canada and Germany and other agreements to likely follow. Green methanol and green ammonia are future fuels for long distance shipping. Several of the large shipping companies have ordered methanol-powered container ships and the first ammonia-powered ships engines are being built.
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Hydrogen Horizons: Unlocking the Potential of Green Hydrogen – Insights from Danfoss on Production, Use, and Efficiency in an exclusive Q&A with Hydrogen Central
