(Potsdam) – Given the current electricity mix in Germany, the production of e-fuels is too inefficient, too expensive, and their availability too uncertain to be used in cars or for heating buildings. Such hydrogen-based fuels should primarily be used in sectors such as aviation or in industrial processes that cannot be electrified. This is one of the results of a study by the Potsdam Institute for Climate Impact Research (PIK).
For most sectors, the direct use of electricity, for example in electric cars or heat pumps, makes more economic sense. If you instead rely primarily on hydrogen-based fuels instead of electrification and maintain combustion technologies, the researchers say, there could be a risk of an extension of dependence on fossil fuels - and further emissions of greenhouse gases.
Applications in aviation and steel production
“Hydrogen-based fuels are an impressively versatile energy source – but their costs and the associated risks are also impressive,” says Falko Ueckerdt from PIK and lead author of the study. “Such fuels as a universal climate solution are a bit of a false promise.” They are not expected to replace fossil fuels across the board and “will likely be in very short supply and uncompetitive for at least another decade.”
Using them on a large scale could ultimately even prolong our dependence on fossil fuels: “If we stick to combustion technologies - in the hope of being able to continue operating them with hydrogen-based fuels - and then the new fuels prove to be too expensive and scarce, we will continue to rely on oil and gas at the end. This endangers short-term and long-term climate goals.”
The researchers see a prioritization of e-fuel demand primarily in sectors that are currently difficult to electrify directly: long-haul flights, parts of chemical production, steel production and some industrial high-temperature processes, according to the study.
Passenger cars with combustion engines use five times more energy using e-fuel than an electric car
Since we are still “a long way from 100 percent electricity from renewable sources,” clean energy must be used efficiently. When using hydrogen-based fuels instead of direct electrification, depending on the technology, “two to fourteen times the amount of electricity is required,” says co-author Romain Sacchi. Efficiency losses occur in both production and consumption - “an internal combustion engine wastes much more energy than an electric one”. If hydrogen-based fuels were produced with the current German electricity mix, greenhouse gas emissions would increase instead of decreasing.
“Only for truly renewable electricity systems will hydrogen-based fuels become an effective way to help stabilize our climate,” says co-author Jordan Everall. Their use “clearly requires the construction of additional systems” for electricity from renewable energies.
E-fuels require an overall political strategy
The authors of the study propose an “overall political strategy” that rests on two pillars: “First, on broad support for technologies, including direct electrification, to promote innovation and initial growth steps. Secondly, on substantial CO2 pricing and an energy tax reform, which together create a level playing field for all technologies – and thus a sensible balance between direct and indirect electrification.”
However, the long-term vision of hydrogen-based fuels is promising, says Gunnar Luderer. By harnessing the huge potential of wind power and solar energy in the global sunbelt in the countries of the South, they could be traded globally, solving renewable energy shortages in densely populated countries such as Japan or Europe. “However, with international and national climate targets requiring immediate emissions reductions, direct electrification should be the priority today to ensure a secure future for all.”
Study
Falko Ueckerdt, Christian Bauer, Alois Dirnaichner, Jordan Everall, Romain Sacchi, Gunnar Luderer (2021): “Potential and risks of hydrogen-based e-fuels in climate change mitigation.” Nature Climate Change [DOI:10.1038/s41558-021- 01032-7]
Photos
E-fuels require an overall political strategy / © European Union
