Hydrogen has been controversial ever since the tragedy of the Hindenburg, an airship filled with it that went down in flames in 1937. Boosters say that the gas is a low-carbon miracle which can power cars and homes. The hydrogen economy, they hope, will redraw the energy map. Sceptics note that several hydrogen investment drives since the 1970s have ended in tears as the gas’s shortcomings were exposed. As we explain, the reality lies in between. Hydrogen technologies could eliminate perhaps a tenth of today’s greenhouse-gas emissions by 2050. That is a sliver—but, considering the scale of the energy transition, a crucial and lucrative one.
Hydrogen is not a primary source of energy like oil or coal. It is best thought of as an energy carrier, akin to electricity, and as a means of storage, like a battery. It has to be manufactured. Low-carbon energy sources such as renewables and nuclear power can be used to separate water (H2O) into its constituents of oxygen and hydrogen. This is inefficient and expensive, but costs are falling. Hydrogen can also be made from dirty fossil fuels but this emits a lot of pollution unless it is coupled with technologies that capture carbon and sequester it. Hydrogen is flammable and bulky compared with many fuels. The implacable laws of thermodynamics mean that converting primary energy into hydrogen and then hydrogen into usable power leads to waste.
All this explains the gas’s tricky history. The oil shocks of the 1970s led to research into hydrogen technologies but they never went far. In the 1980s the Soviet Union even flew a hydrogen-powered passenger jet—the maiden flight lasted just 21 minutes.
Today climate change is causing another wave of enthusiasm. More than 350 big projects are under way and cumulative investment could reach $500bn by 2030. Morgan Stanley, a bank, reckons that annual sales of hydrogen could be worth $600bn by 2050. That is up from $150bn of sales today, which come mainly from industrial processes, including making fertilisers. India will soon stage auctions for hydrogen and Chile is holding tenders for its production on public lands. Over a dozen countries including Britain, France, Germany, Japan and South Korea have national hydrogen plans.
Amid the excitement, it is worth being clear about what hydrogen can and cannot do. Japanese and South Korean firms are keen to sell cars using hydrogen fuel cells, but battery cars are roughly twice as energy efficient. Some European countries hope to pipe hydrogen into homes, but heat pumps are more effective and some pipes cannot handle the gas safely. Some big energy firms and petrostates want to use natural gas to make hydrogen without capturing the associated carbon effectively, but that does not eliminate emissions.
A power plant in Utah plans to store the gas in caverns to supply California. Sunny and windy places that lack transmission links can export clean energy as hydrogen. Australia, Chile and Morocco hope to “ship sunshine” to