Hydrogen promises to be an extremely versatile tool in the race to decarbonise. It can be used to store energy for an unlimited time, and as an energy source for sector coupling, for example in the transport sector. It also can be used to make synthetic fuels that can replace fossil fuels as a feedstock, for example to make plastics. A further advantage is that it can be traded internationally. The World Energy Council estimates that the demand for green synthetic fuels could equal around 50 percent of today's global demand for crude oil from mid-century onwards.

But hydrogen has a big downside. It is dangerously explosive – after all it's used as rocket fuel. This means that it requires a complicated infrastructure. A further drawback is that its use can be highly inefficient, because a lot of energy is lost while it is being made.

Germany sets out to harness the potential of "tomorrow's oil"

Energy transition pioneer Germany, which wants to become climate-neutral by 2050, has set out to harness hydrogen's potential to further its Energiewende, and to make clean hydrogen technology made in Germany an export success. It plans to lay the cornerstone for realising these ambitions with a highly anticipated National Hydrogen Strategy, which is due to be approved by government in the coming weeks.

The government says the climate-neutral gas will play a central role in powering tomorrow's clean economies around the globe, creating huge export opportunities for the country's famed engineering companies.

"Green hydrogen is tomorrow's oil. The flexible energy carrier is indispensable for the energy transition and opens up new markets for us," states the country's research ministry. "The energy of sun and wind can thus be stored, transported and used as required with a versatile energy source […] We must seize the unique opportunity to use our know-how to become the supplier of a global energy transition."

The government has said Germany could create hundreds of thousands of jobs by the middle of the century if it can hold onto its current share of the global market for electrolysers that produce hydrogen, which stands at around 20 percent.

German industry has also become a cheerleader for hydrogen. Ramping up this technology internationally would be "a success both in terms of climate policy and industrial policy," according to Germany's industry association BDI, which insists that "the current hydrogen hype is justified." The country's utility association BDEW also considers the renewable gas an "all-round talent of tomorrow's energy supply."

But E3G's Heilmann and other experts also warn that the focus on green hydrogen must not lead to a neglect of other steps to reduce emissions – for example, increasing efficiency, recycling, and substituting emission-intensive materials such as steel, concrete, and plastics with climate-friendly alternatives wherever possible.