Hydrogen as a fuel for heating and transport is too inefficient and expensive a route for the world to take if it is to reach net zero by 2050, according to David Cebon, a professor at the University of Cambridge and a member of thinktank the Hydrogen Science Coalition.

“The most effective use cases for green hydrogen to reduce emissions are exactly what it is used for now,” Cebon argues, highlighting fertilisers, petrochemicals and glass as carbon-intensive sectors where hydrogen is used in vast quantities. Steelmaking, responsible for 7–8pc of global emissions, is a sector where hydrogen could replace coking coal to directly reduce iron.

“In all these industrial processes, hydrogen will be used for its chemical properties, rather than as a fuel,” Cebon says. “As a fuel for transport and heating, it is a dead end.”

And while hydrogen-based fuels are often touted as a potential key to unlock decarbonisation for hard-to-abate transport such as aviation and shipping, he is sceptical so much focus should be placed on these sectors this decade.

€3.90-5.00/kg – Aurora’s estimated cost of green hydrogen production in Germany

“Shipping is one of the really hard-to-abate sectors, but it is only around 2pc of global emissions,” Cebon says. Aviation similarly represents 2.5pc of emissions.

He notes that 40pc of shipping is to transport fossil fuels between nations and, as such, emissions from this sector will almost halve if countries stop importing coal, oil and gas, and switch to cleaner energy sources.

“How important is that remaining 1pc of emissions? Heating buildings accounts for 25–30pc of emissions and is much more important—if we decarbonise every other sector, and never decarbonised shipping, we would still have gotten rid of 99pc of our emissions.”

Shipping and aviation will also likely require drop-in fuels to rapidly decarbonise, Cebon adds. While biofuels add only a 30pc increase in cost compared with current diesel prices, efuels with hydrogen as a feedstock inflate the cost by as much as six times.

Delay, delay, delay

A focus on hydrogen risks delaying action that can be taken with existing technology, Cebon argues.

A number of European governments, including the UK, are considering blending hydrogen into existing gas networks or mandating the retrofit of domestic heating appliances to run on hydrogen. But Cebon notes that 32 independent studies have already concluded that hydrogen for heating is more expensive, more resource-intensive and associated with larger environmental impacts compared with alternative options such as heat pumps and district heating networks.

“A decision [by the UK government] on whether hydrogen should be included in heating will be taken in 2026, but we already know that it is a poor choice. We should be converting to electric solutions as quickly as possible, not delaying action because of lobbying by the fossil fuel industry.”

Accounting for loss in energy from compression and transmission, around 107GW of green hydrogen would be needed to meet an average UK domestic heating demand of 70GW over the winter, Cebon calculates. “To generate that, with a 75pc efficient electrolyser, you would need approximately 150GW of renewable electricity, or 385GW of installed offshore wind turbines. Compared to the 11GW of offshore wind currently installed in the UK, that is a 35-fold increase in what we have now, just to heat houses.”

Heat pumps, on the other hand, would require 23GW of electricity and heat from the environment to meet average heating demand. Accounting for transmission losses, this works out to 26GW of electricity or 67GW of offshore wind turbines.

“That would still be a lot, but it is more plausible to install six times what we have now than get to 385GW of offshore wind,” Cebon adds.

Supply chain realignment

The industry is investigating options for shipping hydrogen produced at extremely low cost overseas into Europe.

Consultancy Aurora Energy Research has recently calculated that shipping liquid hydrogen produced in Morocco to Germany would cost €4.58/kg ($4.98/kg), competitive with a domestic production cost of €3.90–5.00/kg. Alternative methods such as liquid organic hydrogen carriers and ammonia are also competitive along the same route at €4.68/kg and €4.72/kg respectively, even accounting for extra cost of converting the carrier back to hydrogen.

However, Cebon argues that shipping liquid hydrogen is extremely inefficient. “You lose about 30pc of the hydrogen in the liquefaction process alone,” he says, adding that to prevent boil-off, the hydrogen must be kept at -253°C–just 20°C above absolute zero. While shipping compressed hydrogen on carriers is “possible”, he notes that seven times as many ships as the current fleet of LNG vessels would be needed to carry the same amount of energy.

Instead, Cebon expects that finished products using green hydrogen—fertiliser and steel—will increasingly be produced where raw materials are already extracted and renewable electricity is cheap, such as Australia and Brazil. “Countries like Japan and Germany will lose their steel industries as they cannot afford to continue shipping energy in… and we are likely to see a rearrangement in the global supply chain. It is hard to predict when those industries will disappear—it is a question of when decarbonisation is treated seriously enough by governments to implement international policies with teeth.”

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Author: Polly Martin