Unless hydrogen is “green” hydrogen, or all CO2 produced is genuinely stored for ever, it is not a low carbon fuel

The DfT is pushing the idea of planes fuelled partly by hydrogen, as part of its “Jet Zero” strategy – hoping to find ways in which people can continue to fly, without huge carbon emissions that make reaching the UK target of net zero impossible. However, the Government’s “Jet Zero Council” said, at the end of June, that government was launching “the first round of £3 million Zero Emission Flight Infrastructure (ZEFI) competition, supporting development of infrastructure required to aid electric and hydrogen aircraft such as charge points for planes.” Hydrogen can be produced in various ways, most using a fossil fuel and producing CO2 in the process. The hydrogen could only be a “low carbon” fuel if all this CO2 is captured and stored, for ever – not just reused (which is what usually happens at present.) Now a study by academics at Cornell and Stanford universities in the US, warned that blue hydrogen (produced by ‘steam reforming’, needing carbon capture and storage for the CO2 created) could be up to 20% worse for the climate than fossil gas owing to the emissions that escape during its production, multiplied by the amount of gas required to make the equivalent amount of energy from hydrogen.



Study finds blue hydrogen worse than gas or coal

By Adis Ajdin (Splash247)

August 16, 2021

The carbon footprint of creating blue hydrogen is more than 20% greater than using either natural gas or coal directly for heat, or about 60% greater than using diesel oil for heat, according to joint research by Cornell and Stanford universities in the US.

The paper, which was published in Energy Science and Engineering, warned that blue hydrogen may be a distraction or something that may delay needed action to truly decarbonise the global energy economy.

A research team claimed blue hydrogen requires large amounts of natural gas to produce and said that even with the most advanced carbon capture and storage technology, there are a significant amount of CO2 and methane emissions that won’t be caught.

Blue hydrogen sounds good, sounds modern and sounds like a path to our energy future, it is not

Professors from the universities calculated that these fugitive emissions from producing hydrogen could eclipse those associated with extracting and burning gas when multiplied by the amount of gas required to make an equivalent amount of energy from hydrogen.

The paper comes hot on the heels of the United Nations’ Intergovernmental Panel on Climate Change report claiming methane has contributed about two-thirds as much to global warming as CO2 and as many governments are looking to invest in hydrogen production.

Robert Howarth, a Cornell University professor and co-author of the study, said: “Political forces may not have caught up with the science yet. Even progressive politicians may not understand for what they’re voting. Blue hydrogen sounds good, sounds modern and sounds like a path to our energy future. It is not.”

The UK is high up on the list of countries aiming to put blue hydrogen at the core of its energy transition agenda. UK energy consultancy Xodus recently launched a new report urging a bolder vision to enable the country to become a global leader in the adoption of hydrogen. The researchers, on the other hand, recommended a focus on green hydrogen, which is made using renewable electricity to extract hydrogen from water, leaving only oxygen as a byproduct.

“This best-case scenario for producing blue hydrogen, using renewable electricity instead of natural gas to power the processes, suggests to us that there really is no role for blue hydrogen in a carbon-free future. Greenhouse gas emissions remain high, and there would also be a substantial consumption of renewable electricity, which represents an opportunity cost. We believe renewable electricity could be better used by society in other ways, replacing the use of fossil fuels.”





Open Access

How green is blue hydrogen?

First published: 12 August 2021

Funding information:   Funding was provided by the Park Foundation and by Cornell University


Hydrogen is often viewed as an important energy carrier in a future decarbonized world. Currently, most hydrogen is produced by steam reforming of methane in natural gas (“gray hydrogen”), with high carbon dioxide emissions. Increasingly, many propose using carbon capture and storage to reduce these emissions, producing so-called “blue hydrogen,” frequently promoted as low emissions. We undertake the first effort in a peer-reviewed paper to examine the lifecycle greenhouse gas emissions of blue hydrogen accounting for emissions of both carbon dioxide and unburned fugitive methane. Far from being low carbon, greenhouse gas emissions from the production of blue hydrogen are quite high, particularly due to the release of fugitive methane. For our default assumptions (3.5% emission rate of methane from natural gas and a 20-year global warming potential), total carbon dioxide equivalent emissions for blue hydrogen are only 9%-12% less than for gray hydrogen. While carbon dioxide emissions are lower, fugitive methane emissions for blue hydrogen are higher than for gray hydrogen because of an increased use of natural gas to power the carbon capture. Perhaps surprisingly, the greenhouse gas footprint of blue hydrogen is more than 20% greater than burning natural gas or coal for heat and some 60% greater than burning diesel oil for heat, again with our default assumptions. In a sensitivity analysis in which the methane emission rate from natural gas is reduced to a low value of 1.54%, greenhouse gas emissions from blue hydrogen are still greater than from simply burning natural gas, and are only 18%-25% less than for gray hydrogen. Our analysis assumes that captured carbon dioxide can be stored indefinitely, an optimistic and unproven assumption. Even if true though, the use of blue hydrogen appears difficult to justify on climate grounds.

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Primary colours of the rainbow

Green hydrogen

Green hydrogen is extracted using a method that does not produce GHG emissions. As the name suggests, its production is sustainable and environmentally friendly. Green hydrogen is most commonly produced using a device called an electrolyser. Electrolysers use electricity to split water into hydrogen and oxygen. The key to this method of producing green hydrogen is that the electricity that powers the electrolyser comes from renewable sources, such as wind, solar, which have no associated GHG emissions. There are also pathways to produce green hydrogen from waste biomass.

Blue hydrogen

Blue hydrogen is produced using a process called ‘steam reforming’, which uses steam to separate hydrogen from natural gas. This process does produce GHGs, but carbon capture and storage technologies capture and store those emissions.

Grey hydrogen

Grey hydrogen is also extracted from natural gas using steam reforming but in this case, relevant technologies don’t capture resulting emissions. Instead, they are released into the atmosphere.

Brown and black hydrogen

Brown hydrogen (made from brown coal) and black hydrogen (made from black coal) are produced via gasification. It’s an established process used in many industries that converts carbon-rich materials into hydrogen and carbon dioxide. As a result, gasification releases those by-products into the atmosphere.

However, if technology ends up storing those emissions, that hydrogen can sometimes be called blue.

Turquoise hydrogen

Turquoise hydrogen describes hydrogen produced when natural gas is broken down into hydrogen and solid carbon via pyrolysis. This method uses heat to break down a material’s chemical make up. It’s seen as ‘low carbon’ as the hydrogen production process doesn’t emit any GHGs. But there can be emissions associated with the mining and transport of natural gas that is used as the starting product.



Jet Zero Council keeps up momentum with £3 million government funding for zero emission flight infrastructure


30th June 2021

Competition will fund critical research into electric and hydrogen aircraft to support aviation reach net zero by 2050.

Launching the first round of the ZEFI competition, delivered by the Connected Places Catapult – the government will award businesses and universities around the UK up to £50,000 each to pioneer critical research into infrastructure, such as charge points and hydrogen fuelling tanks, that will enable the mass uptake of electric and hydrogen aircraft.

  • government launches first round of £3 million Zero Emission Flight Infrastructure (ZEFI) competition, supporting development of infrastructure required to aid electric and hydrogen aircraft such as charge points for planes

Government reveals plans for £4bn hydrogen investment by 2030

Low-carbon hydrogen economy could also create thousands of jobs

Energy correspondent (the Guardian)


The government hopes to attract at least £4bn of investment to the hydrogen economy by 2030 under plans to produce the equivalent of enough hydrogen to replace fossil fuel gas for heating and cooking in about 3m households in the UK.

The government has published its long-awaited plans for a UK-wide hydrogen economy, which it says could be worth £900m and create more than 9,000 high-quality jobs by the end of the decade, rising to £13bn and 100,000 new jobs by 2050.

The strategy document lays out its efforts to attract investment in 5 gigawatts of hydrogen production by 2030, which would mostly power heavy industry, as well as transport and up to 70,000 homes. It suggests hydrogen could cover 20-35% of the UK’s energy consumption by 2050, providing a clean alternative to oil and gas in energy-intensive industries, power and transport.

It proposes a series of industry consultations to help establish a subsidy system to support large hydrogen projects to decarbonise areas that cannot run on electricity.

However, the plans remain dogged by uncertainty over how the government will determine a fair subsidy for the multibillion-pound projects and whether the cost will be shouldered through household bills or by the Treasury. The government has promised more clarity after an industry consultation later this year.

Matthew Fell, the chief UK policy director at the CBI, said the strategy included important steps for the economy-wide hydrogen sector.

“However, to truly capitalise on those large-scale economic opportunities, and unlock the private sector finance needed, firms will now be looking for the government to provide detailed policies and standards for hydrogen production and application,” he said.

The hydrogen projects under development include “green hydrogen” schemes, which extract hydrogen from water, leaving only oxygen as a byproduct, and “blue hydrogen”, which extracts hydrogen from fossil fuel gas before trapping the greenhouse gas emissions that are left behind.

However, last week a study by academics at Cornell and Stanford universities in the US, warned that blue hydrogen could be up to 20% worse for the climate than fossil gas owing to the emissions that escape during its production, multiplied by the amount of gas required to make the equivalent amount of energy from hydrogen.

The government says it will set out emissions standards for blue hydrogen projects to ensure they capture enough greenhouse gas emissions during hydrogen production to qualify as “low carbon”, but many environmentalists and green energy producers have put pressure on the government to drop its support for blue hydrogen altogether.

The strategy paper does not set out a vision for the balance of blue and green hydrogen in the future, despite a clear instruction from its official climate advisers at the Committee on Climate Change (CCC) to include a pathway for each to 2035.

The CCC has supported plans for a “blue hydrogen bridge” to play a role in supplementing green hydrogen over the near-term because it could begin displacing fossil fuels sooner and at a greater scale than green hydrogen projects. However, critics of blue hydrogen fear a long-term commitment could extend the UK’s reliance on fossil fuels.

Doug Parr, the chief scientist for Greenpeace UK, warned that producing large quantities of hydrogen from fossil gas would lock the UK “into costly infrastructure that is expensive and … may be higher carbon than just burning the gas”.

Dan McGrail, the chief executive of RenewableUK, said the national strategy “doesn’t focus nearly enough on developing the UK’s world-leading green hydrogen industry” and should “set out a clear ambition for green hydrogen”.

“We’re urging the government to set a target of 5GW of renewable hydrogen electrolyser capacity by 2030 as well as setting out a roadmap to get us there, to show greater leadership on tackling climate change,” he said.

 This article was amended on 17 August 2021. The government originally stated that the hydrogen production could replace fossil gas in about 3m UK households. It has since clarified that it was referring to the equivalent of current household fossil gas usage and that the hydrogen will predominantly be used by heavy industry. https://www.theguardian.com/environment/2021/aug/17/uk-homes-low-carbon-hydrogen-economy-jobs?.


Jet Zero consultation – what it says on “sustainable aviation fuels” (spoiler…crazy over-optimism)

The DfT’s consultation on reducing aviation carbon emissions, “Jet Zero” places a lot of faith in finding novel, low carbon fuels, so people can continue to fly as much as they want. These are called “Sustainable Aviation Fuels” (SAF). The consultation says SAF “could play a key role in decarbonising aviation, whilst also representing an industrial leadership opportunity for the UK.” The economic opportunity aspect, and producing jobs, is key for the DfT.  They say “Many experts view SAF as the only alternative for long-haul flights up to 2050, which are the flights with the biggest climate impact.” The DfT is hoping SAF could “result in over 70% CO2 emissions saving on a lifecycle basis and could deliver net zero emissions with the addition of greenhouse gas removal technologies.” SAF would either be biogenic, non-biogenic (from wastes) or made using zero-carbon electricity.  There are huge problems, glossed over by the consultation. A key problem is that “there is currently no comprehensive global regulatory standard for SAF sustainability. The UK is therefore active at ICAO in negotiating for a full set of sustainability criteria for SAF.” The DfT “will shortly consult on a UK SAF mandate setting out our level of ambition for future SAF uptake.”

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