The problem with wind and solar is intermittency and storage. Hydrogen is often seen as the solution – an ideal way to store this energy. The availability of cars like the Toyota Mirai, or hydrogen-powered buses, leads many people to believe a hydrogen revolution is just around the corner. In this article I explain why hydrogen is not the right path to follow.
The problem is efficiency. If we start with electricity from solar, wind or nuclear, then we want it to stay as electricity for as long as possible. Electricity can produce mechanical work with at least 90% efficiency. Using a heat pump we can effectively heat a building with more than 100% efficiency – typically between 200% and 400%. Producing hydrogen, compressing it, pumping it and turning it back into electricity or mechanical work, all involve significant losses of energy. Therefore, fuel cell vehicles are four or five times less efficient than battery vehicles.
Some argue hydrogen is the only option for heavy trucks, but electrification of roads and railways is not only more efficient but also less capital intensive if the increased power generation is taken into account. For example, the cost of electrifying the UK’s major roads has been estimated at $39 Billion, but the improved efficiency compared to hydrogen would reduce the required investment in new solar and wind installations by about $180 Billion.
Hydrogen should have a limited role in grid storage and industrial applications. Widespread use of hydrogen for transport and heat will greatly increase the cost of decarbonization. Read my full article about the state of the hydrogen economy published on engineering.com