Dirty "gray" hydrogen, produced using coal and/or natural gas, currently retails for around US$1-$2 per kilogram, according to KPMG. From the same report, "green" hydrogen – produced with zero emissions using renewable energy, water and electrolyzers – costs between $2.50-$6.

The USA's new Inflation Reduction Act squeaked past the Senate in a tiebreaker vote on the weekend, and will soon be passed by the House. It's a $739-billion shadow of the US$3.5-trillion Build Back Better act originally proposed by Democrats in 2021, but it still marshals more than $360 billion toward clean energy – the largest such investment in American history.

And tucked away in its arcane text is a tax credit of up to $0.60 per kg for green hydrogen – defined as hydrogen that can be proven to create less than 0.45 kg (1 lb) of lifecycle CO2e emissions per kg of hydrogen, as verified by a third party, for projects that begin construction before 2033.