The hype and reality of hydrogen as a power source
The car show Top Gear was notorious for its disdain of environmentally friendly cars, so viewers were stunned in 2008 when the hosts confidently predicted that hydrogen fuel cells would power the cars of the future. But today these cars remain rare. What went wrong?
“Going to hydrogen fuel cell automobiles was not as easy as they thought,” explains Fredrik Östman, Wärtsilä’s General Manager of Ecosystem Innovation. “There have been improvements in capacity and efficiency, but the capital outlay and operating expenses for hydrogen fuel cells remain high. However, the biggest challenge is hydrogen itself.”
Where do you get hydrogen?
The attractiveness of hydrogen is that it is clean: during combustion, the only waste product is pure water. No CO₂ is released in the atmosphere. However, hydrogen gas doesn’t occur naturally in ways we can easily access. It has to be produced, such as by reacting natural gas with steam or using electricity to split water into hydrogen and oxygen.
“The production of hydrogen requires huge amounts of energy,” continues Östman. “If you use fossil fuels to produce this energy you are emitting CO₂ into the atmosphere and are defeating the purpose. You have to use renewable energy, such as wind or solar, or else you are just making things worse.”
The prices of renewable energy have decreased so this is now a viable option to produce hydrogen. In various places around the world, the hydrogen economy is slowly advancing.
The hydrogen economy
The Orkney islands off the north-eastern coast of Scotland produces 120% of their electricity demand. They use surplus wind and tidal energy to produce hydrogen, which is used to heat local buildings and power vans and ferries. Meanwhile, Japanese auto manufacturers are investing heavily in hydrogen fuelling stations and London uses hydrogen public buses.
Hydrogen is also used in larger vehicles. Germany has introduced the world’s first hydrogen-powered train, while Wärtsilä is working with Norwegian transport operator Boreal Sjø to develop a hydrogen ferry in Norway.
Yet don’t be fooled: major problems remain and many of these projects are simply demonstrations or proofs-of-concept.
“The lifecycle of a fuel cell is short for maritime applications,” explains Östman. “The hydrogen is difficult to handle and may need to be kept cold or under pressure. Hydrogen has a low energy density, so you need larger tanks to have the same capacity as LNG, for example. Also, the entire infrastructure is missing.”
The challenges seem daunting, but hydrogen is versatile when it comes to its ability to be a power source.
“Our view is that LNG is an excellent way to make a significant dent in greenhouse gas emissions and synthetic fuels based on hydrogen will probably be the long-term solution,” Östman says. “In addition, we will probably see more applications using fuel cells and batteries in the future, but the combustion engine will remain as the main power converter for a considerable time.”
“There are several paths to using hydrogen to decarbonise,” explains Jero Ahola, Professor of Energy Efficiency at Lappeenranta University of Technology. “We can use hydrogen in fuel cells. We can mix hydrogen with methane to use in gas engines. Renewable electricity-based hydrogen with CO₂ or N₂ can produce synthetic fuels to power ships with Power-to-X processes. We will probably use all of these options, and the only question is what is most feasible for which task.”
Ahola agrees with Östman that hydrogen will be important in the future of marine energy. Since ships generally sail port-to-port the infrastructure can be concentrated in those areas. Harbours will also have high volumes of consumption which can help bring costs down.
“Hydrogen will probably be used in different ways in the maritime industry,” says Ahola. “Fuel cells with gaseous hydrogen would be viable for ferries in their short trips. However, for a long journey, such as from the EU to the USA, you might instead use synthetic ammonia or methanol and then split the hydrogen out to be used as a fuel in fuel cells. This removes some of the storage difficulties.”
As the hydrogen economy continues to evolve, Ahola has one more tip when it comes to comparing various fuel sources.
“Someone might say fossil fuels are ‘cheaper’ than hydrogen, but this is not factoring in the cost of the damage being done to the environment,” he says in conclusion.