A way out of the heat pump obsession? Hydrogen is repeatedly brought into play as a climate-neutral heating alternative - which should also enable homeowners to keep their gas heating. However, German energy expert Dr Jan Rosenow from the University of Oxford writes: "Hydrogen is extremely important - but can hardly play a role in heating.”

The end of all hydrogen dreams? In a working paper, the Federal Ministry of Economics under Minister Robert Habeck (Greens) considers the future of the gas network. The reason: in a future in which heating will mainly be provided by heat pumps(/thema/waermepumpe/), there will no longer be a need for a huge gas network. In the paper, the Ministry is also sceptical about heating with hydrogen using the gas grid - something the coalition partner from the FDP(/organizations/fdp/) had repeatedly advocated in the spirit of so-called "technological openness

"A decentralized hydrogen supply, especially for heating customers or individual households, currently appears to be a viable option due to the high costs of hydrogen in the heating sector and, above all, due to the expected limited availability of hydrogen. available quantities," the paper states. So will heating with hydrogen not be possible in the future after all? How realistic is this hope anyway? Energy expert Jan Rosenow has investigated for FOCUS online Earth already summarized the opportunities of hydrogen as a heating solution in April last year - with a clear conclusion.

Germany's climate targets mean that there is no longer any room for the continued use of fossil fuels in the future energy system, not even for heating buildings. Since the beginning of the year, 65 percent of heating systems must be powered by renewable energies. One of the possible options is to use hydrogen. In practice, however, hydrogen will hardly play a role in heating, will be significantly less efficient and more expensive and will lead to uncertainty among consumers.

Hydrogen as a "lifebuoy" for the fossil fuel industry?

Germany's climate targets mean that there is no longer any room for the continued use of fossil fuels in the future energy system, not even for heating buildings. Since the beginning of the year, 65 percent of heating systems must be powered by renewable energies. One of the possible options is to use hydrogen. In practice, however, hydrogen will hardly play a role in heating, will be significantly less efficient and more expensive and will lead to uncertainty among consumers.

This is not to say that hydrogen cannot play an important role in the energy transition

Hydrogen from renewables is a valuable energy carrier with many specific applications for which there are few alternatives. Hydrogen is needed in large quantities for the decarbonization of industrial sectors such as the chemical industry. In shipping, hydrogen is likely to be essential. In addition, hydrogen can play a role as a seasonal storage medium for electricity generation at times when production from renewables is insufficient. However, costs and efficiency losses are the limiting factors for this "power-to-gas- to-power" route. Why is the use of hydrogen to heat our buildings on a large scale so problematic?

Heating with hydrogen is wasteful

Firstly, the production of "green hydrogen" through electrolysis is extremely wasteful compared to the direct use of electricity from renewable sources to run heat pumps or charge electric vehicles. To heat a house with green hydrogen, around five times more wind or solar power is needed than to heat the same house with an efficient heat pump. Due to this inefficiency, the required expansion rates for renewable energies would be extremely difficult: 561 terawatt hours of heating oil and gas were consumed for space heating and hot water in 2021. To replace this with green hydrogen, around 800 terawatt hours of electricity from renewable energy would be required - more than three times as much electricity as was generated from renewable energy in 2023.

In comparison, heat pumps need around 160 terawatt hours of electricity to provide the same amount of heating. However, the expansion of renewable energies to replace fossil fuels is already progressing too slowly to meet the climate targets. It is highly unlikely that Germany has the money and the land to build five times as many wind and solar plants just to continue using boilers.

Couldn't we just import green hydrogen instead of producing it in Germany? In principle, yes, but the problem is that there is hardly any green hydrogen available at the moment - the total global green hydrogen production in 2021 could provide just 0.2 percent of the energy required for space heating and hot water. And the transportation of hydrogen is by no means trivial.

Heating with hydrogen is expensive

Secondly, green hydrogen is not cheap: according to recent studies by Aurora, green hydrogen produced in Germany will cost around 12 to 15 cents per kilowatt hour in 2030. Then there are the transportation and distribution costs, because the hydrogen also has to be delivered to the end customer. 

Despite historic record prices for gas and heating oil, this figure is still significantly higher than current household energy prices. Diverting the limited supply of green hydrogen to the buildings sector would also drive up the cost of hydrogen in key industries where it is most needed. The use of green hydrogen in the building and transportation sectors could lead to a doubling of hydrogen costs due to the higher demand, as an analysis by Aurora shows.ldn't we just import green hydrogen instead of producing it in Germany? In principle, yes, but the problem is that there is hardly any green hydrogen available at the moment - the total global green hydrogen production in 2021 could provide just 0.2 percent of the energy required for space heating and hot water. And the transportation of hydrogen is by no means trivial.

Heating with hydrogen is expensive

Secondly, green hydrogen is not cheap: according to recent studies by Aurora, green hydrogen produced in Germany will cost around 12 to 15 cents per kilowatt hour in 2030. Then there are the transportation and distribution costs, because the hydrogen also has to be delivered to the end customer. 

Despite historic record prices for gas and heating oil, this figure is still significantly higher than current household energy prices. Diverting the limited supply of green hydrogen to the buildings sector would also drive up the cost of hydrogen in key industries where it is most needed. The use of green hydrogen in the building and transportation sectors could lead to a doubling of hydrogen costs due to the higher demand, as an analysis by Aurora shows.ldn't we just import green hydrogen instead of producing it in Germany? In principle, yes, but the problem is that there is hardly any green hydrogen available at the moment - the total global green hydrogen production in 2021 could provide just 0.2 percent of the energy required for space heating and hot water. And the transportation of hydrogen is by no means trivial.

Gas grids are not ready for hydrogen

Thirdly , converting a gas network to a hydrogen network is not easy and households that want to install "H2-ready heating systems" can only do so under strict conditions.The gas network operator must submit plausible evidence in a hydrogen transformation plan and investment plan and have it reviewed by the regulatory authority. Furthermore, the gas network operator must guarantee the building owner that the hydrogen infrastructure will be put into operation within ten years, but no later than 1 January 2035. If this timetable is not met, the building owner must remove the "H2-ready heating system".

How realistic is it that gas network operators will be able to do this? Hydrogen is a different gas with different properties. It can corrode older pipes. It is more flammable. In addition, all existing meters and heaters would have to be replaced, not just those that have been replaced with "H2-ready heaters" at the end of their service life. All at a high cost to the gas network operators.

All this does not mean that there is no application for hydrogen in the heating sector at all. Hybrid heat pumps could play a role by using a small amount of hydrogen as back-up during long cold spells. Hydrogen can also play a role in the electricity supply and in this way indirectly support the electrification of the heat supply. And waste heat from electrolysers can and should be utilised in district heating networks.

But suggesting that we will be heating the majority of our buildings with hydrogen in the foreseeable future is not helpful and is a diversionary tactic that unsettles consumers. Instead, the heating transition should focus on solutions that are already proven and available today.

This article is also available in German in Der Spiegel. illuminem Voices is a democratic space presenting the thoughts and opinions of leading Sustainability & Energy writers, their opinions do not necessarily represent those of illuminem.