The first academic paper to model green hydrogen usage on an hour-by-hour basis in a carbon-neutral energy system has concluded that due to “high societal costs and practicality issues… hydrogen cannot be considered a large-scale solution for heating and transport”.
“Direct hydrogen technologies always increase the cost of the energy system,” adds the study by academics at Aalborg University in northern Denmark.
The paper, entitled On the feasibility of direct hydrogen utilisation in a fossil-free Europe, published in the International Journal of Hydrogen Energy, also found that it would be cheaper to use liquid e-fuels derived from H2 in transport, rather than hydrogen directly “due to high infrastructure costs and respectively low energy efficiency [of H2]”.
And the academics looked into the use of H2 for decarbonising the power sector and heavy industry, concluding that “hydrogen for electricity production is beneficial only in limited quantities to restrict biomass consumption, but increases the system costs due to losses”, and that “electrification and e-methane may be more feasible” for hard-to-abate industrial sectors, with the latter able to be utilised as a direct replacement for the fossil gas used today.
Nevertheless, the study — which examined a fossil-free energy system across the EU and UK in 2050, including the costs of upgrading electricity grids and gas networks — says that huge amounts of green hydrogen will still be needed.
“Hydrogen will be an important energy carrier, not as an end-fuel, but rather as feedstock for the production of e-fuels,” it explains.
“Despite the poor results for direct hydrogen utilisation in almost all energy sectors, hydrogen utilisation is high across all scenarios analysed, with the reference scenario alone producing 3,000TWh [of] H2 to supply the European transport and industry demands.
“Such large demands also mean that over 4,000TWh of electricity are needed solely for this purpose, clearly discarding the idea that hydrogen can be produced on excess electricity at a low cost.”
The 3,000TWh — equivalent to 90.9 million tonnes of hydrogen — would require 700GW of electrolysers and four days’ worth of hydrogen storage to ensure an “energy system with a high level of flexibility”.
“For these reasons, resources must be prioritised towards those parts of the energy system that need it [ie, hydrogen] most and not wasted where other technological solutions strike a better balance between energy efficiency and costs,” the study says.
Like 32 other independent studies before it, the Aalborg paper sees no argument for the large-scale use of hydrogen in heating, pointing out that this is only being considered in the UK and the Netherlands.
“Using hydrogen for space and hot water heating increases the [total EU+UK] energy system costs by 7% [to] 23% compared to the reference scenario, costing between €60bn-200bn more annually, making it one of the most abrupt cost increases among the scenarios investigated,” the document explains.
“Overall, the use of hydrogen for heating, especially in urban contexts where district heating can be a viable alternative, radically increases the costs of the energy system. Between 120 and 320GW of additional offshore wind will be necessary to handle the decrease in system efficiency.”
Building the required hydrogen distribution network “would not just incur high costs with reconverting and building new pipes, but would also raise practicality issues”, the study says.
Many components would need to be upgraded or replaced to handle the smaller molecules of hydrogen, including pipes, meters, burner heads and seals, it explains.
Another problem is that burning hydrogen in boilers and cooking stoves “will emit nitrous oxide, a gas with high global warming potential, which would still not solve the problem of emissions from the heating sector”.
“Emission control may be a solution at the boiler level, however, at a higher cost and lower fuel efficiency, and is not an option for open-flame cooking.”
It also points to potential safety issues with burning hydrogen in the home, as well as the fact that the fossil-gas supply would have to be switched off until all homes on a distribution network have been successfully converted to run on H2.
If 50% of cars are run on hydrogen in Europe in 2050, the overall system costs would be $290bn higher than if they were all electric, the study finds.
And it would be a similar story if buses, trains, light-duty vehicles (ie, vans) and heavy-duty vehicles were powered by hydrogen, rather than batteries, albeit to a lesser degree.
“In general, the use of hydrogen end-fuel for transport is more expensive than not [directly] using hydrogen for this purpose,” the study says.
“Cost differences occur due to the higher investment in the energy system (wind turbines, electrolysis), higher cost of vehicles (fuel-cell vehicles are generally considered more expensive than ICE or BEV [internal combustion engine or battery electric vehicles]), and hydrogen infrastructure, which makes up for a significant share of the overall annual costs since, in this case, it includes hydrogen distribution grids and fuelling stations.
“For heavy-duty vehicles, the higher costs are primarily caused by the larger investments in new vehicles since hydrogen fuel cell HDVs are more expensive than ICE HDVs. Secondly, a large dedicated pan-European H2 fuelling station network will have to be established to handle the 5-8 million trucks using this fuel.”
The study does not, however, directly address industry concerns about how to supply the megawatts of power that would be required at each charging location if multiple long-distance trucks with large batteries need to be fast-charged at the same time.
The paper then explains that, perhaps counterintuitively, it would be cheaper to power vehicles with e-fuels derived from hydrogen, than the hydrogen directly.
“Even though their round-trip efficiency is lower, e-fuels can reuse existing infrastructure for fuel distribution and storage and are more adaptable to existing propulsion systems and transport demands, in particular, aviation, heavy-duty long-distance road transport or shipping.
“Unless hydrogen vehicles and infrastructure, in general, become cheaper than internal combustion engines and liquid fuel storage, then it will be very difficult to motivate the choice of hydrogen as an end-fuel.”
However, this is perhaps a flawed argument as the fine print shows that when talking about e-fuels (ie, electrofuels derived from electricity), it is referring to e-methanol for vans, trucks, buses and trains — which do not use methanol today, nor is there an existing methanol refuelling infrastructure for land transport.
And strangely, its calculations on shipping are based on the use of e-methane, rather than the e-ammonia and e-methanol that the maritime sector is actually planning to use.