A scientific paper released Aug. 12 that said low-carbon hydrogen in heating was significantly worse for the environment than using natural gas poses a challenge for the UK's forthcoming hydrogen strategy, expected to include support for both low-carbon and renewable production.
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Renewable, or green, hydrogen is produced from the electrolysis of water powered by renewable electricity, and low-carbon, or blue, production is via steam methane reforming of natural gas with carbon capture and storage.
The study from scientists at Cornell and Stanford universities concludes, however, that using blue hydrogen for heating had 20% higher greenhouse gas emissions than using natural gas.
Speaking to S&P Global Platts on Aug. 10, co-author of the study Robert Howarth, Professor of Ecology and Environmental Biology at Cornell University, cautioned against supporting blue hydrogen on environmental grounds.
"I definitely think that would be a mistake," Howarth said.
The UK government has set a target of 5 GW of low-carbon or renewable hydrogen production capacity by 2030 in its 10-point plan for a "green industrial revolution", and is expected to give support for both technologies in a forthcoming hydrogen strategy.
"Low-carbon hydrogen will be essential for meeting our legally binding commitment to eliminating the UK's contribution to climate change by 2050, with more details to be set out in our forthcoming Hydrogen Strategy," a UK government spokesperson said in an email, responding to the findings.
"Independent reports, including that from the Climate Change Committee, show that a combination of blue and green hydrogen is consistent with reaching net zero but alongside the Strategy, we will consult on a new UK standard for low-carbon hydrogen production to ensure the technologies we support make a real contribution to our goals," the spokesperson said.
The UK has delayed publication of its long-anticipated hydrogen strategy since the start of 2021, and is expected to release the document in the coming weeks.
The UK government's Department for Business, Energy and Industrial Strategy has said it would pursue a twin-track approach to developing low-carbon hydrogen, with support for both green and blue production pathways.
The strategy is expected to include measures for contracts for difference as well as incentives for green hydrogen in transport and large-scale industrial processes, ITM Power CEO Graham Cooley, who also sits on the UK government's Hydrogen Advisory Council, said in June.
BEIS deputy director, hydrogen economy, Rita Wadey said in May the strategy would consider carbon intensity as the primary factor in market development.
The Netherlands and Norway, with offshore subsea storage potential in depleted oil and gas reservoirs, also support the development of blue hydrogen.
The EU, meanwhile, is explicitly supporting renewable hydrogen in its policies and legal framework for achieving net-zero emissions by mid-century.
Low-carbon or renewable
Climate organizations were critical of the UK's focus on blue hydrogen.
"A climate-safe future demands a rapid and steep reduction in greenhouse gases, but today's new report warns that fossil fuel derived blue hydrogen is far from a truly zero emissions fuel," European climate think tank E3G Senior Policy Advisor, Clean Economy, Juliet Phillips said in a statement.
"Worryingly, the UK government has so far allocated around 75% of public investments in hydrogen towards this fossil-based fuel," Phillips said. "We encourage the UK government to rethink its risky strategy of pursuing a 'twin track' approach of supporting both blue and green hydrogen, and instead focus on becoming a global leader in green hydrogen sourced from renewables."
"This landmark paper sheds light on the key unknown in the UK's hydrogen debate: the greenhouse gas footprint of blue hydrogen," David Cebon, Professor of Mechanical Engineering at the University of Cambridge said in a statement.
"The calculation method is rigorous, the assumptions are all solid and the results are stark," Cebon said. "Blue hydrogen cannot be considered 'low-carbon' or a 'clean' solution."
"Politicians must take notice of this important finding before considering investment in blue hydrogen under the premise that it supports our climate goals," he added. "The only hydrogen we can consider truly emissions-free, is that made from renewable energy such as green hydrogen."
Blue hydrogen production is currently much cheaper than electrolysis, but green hydrogen costs are expected to come down rapidly with the rollout of more renewable power generation and cheaper electrolyzers as production increases.
Platts assessed the cost of producing hydrogen via alkaline electrolysis in the UK (including capex) at GBP6.31/kg ($8.73/kg) Aug. 11. PEM electrolysis production was assessed at GBP7.66/kg, while blue hydrogen production by autothermal reforming was GBP2.69/kg (including capex, CCS and carbon).