Blue hydrogen will be needed in the coming years, despite its greenhouse gas emissions, because it will simply not be possible to meet H2 demand purely with green hydrogen, according to influential independent analyst Michael Liebreich.
The founder of BloombergNEF (BNEF) calculated that just replacing the current annual global demand for grey hydrogen with the green variety would require all the wind and solar power currently installed around the world.
And he found that meeting the International Energy Agency's hydrogen demand forecasts (in its 2050 net-zero scenario) purely with green H2 would require all the wind and solar power predicted by BNEF to be installed globally (see chart below).
“Try to meet future demand with green hydrogen and you risk absorbing all future wind and solar too, even though [existing] uses [such as fertiliser production and oil refining] should start to decline at some point,” he wrote in a LinkedIn post.
“What this means is that if you’re proposing any increase in the use of hydrogen, irrespective of whether it’s… steel and long-duration storage... aviation and shipping... or heating or transportation — and you are a green hydrogen fundamentalist, you need to explain where the supply is going to come from.”
He added: “Let me be absolutely clear. I'm not promoting blue hydrogen. Of course green hydrogen has the potential to be better from a climate perspective. All I'm doing here is pointing out the sheer scale of renewable power needed to meet the demand for hydrogen in a decarbonizing global economy.
“This is why I have made my peace with blue hydrogen. I simply cannot see sufficient quantities of green hydrogen being produced fast enough and with low enough environmental impacts to meet demand.”
Liebreich explains that his peace with blue hydrogen is, however, conditional. “I have already been very clear that for blue hydrogen to be compatible with net zero, it must achieve very high CO2 capture rates — well above 90% — and very low fugitive [methane] emissions rates, in the low fractions of a percent.
“These things are within the realms of science and engineering; they need to be brought into the realms of policy and economics.”
Liebreich tells Recharge that decarbonising the global electricity supply with renewable energy will be “hard enough”, let alone potentially doubling that capacity to produce green hydrogen — regardless of how cheap wind and solar might be.
“There are these constraints on [renewables] growth that are real — legislative inertia, learning effects, planning permission and so on,” he says.
And he points out that large-scale use of hydrogen in transportation and heating — as many in the energy industry are lobbying for — would “obliterate” any hope of meeting future hydrogen demand with renewable H2.
“If you really are a green hydrogen fundamentalist, then you absolutely cannot be doing hydrogen for heating or for transport.”
This is because using green hydrogen for transport and heating requires far more power than pure electric solutions such as EVs and heat pumps.
According to a recent study, green hydrogen for heating has an energy efficiency of 46% — in other words, for every 100kWh of renewable energy used to produce green H2, only 46kWh of heat is produced, due to energy losses in the production, storage and transportation of the gas. By contrast, heat pumps produce an energy efficiency of 270%, meaning that for every 100kWh of renewable energy, 270kWh of heat is produced.
And according to European NGO Transport & Environment, green hydrogen for fuel-cell vehicles has an energy efficiency of 30%. So for every 100kWh of renewable energy, only 30kWh are useable on the road, due to energy losses in the electrolysis process, the storage and distribution of hydrogen, and converting the H2 back to electricity inside the vehicle. This compares with 77% efficiency for EVs.
Liebreich wrote in his LinkedIn post that if blue hydrogen cannot be produced with low emissions — as suggested in a recent controversial academic paper — “then then I'm really not sure... how we get to net zero on any timeframe compatible with the Paris Agreement, while preserving human progress. The lives and lifestyles of literally billions of people hang on the question”.