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Hydrogen has long been regarded as a key element in the success of the energy transition because it links the energy, transportation, building and industry sectors and can be used as a CO2-neutral energy source, storage and supply medium.
By Henning Sandfort, CEO Building Products, Siemens Smart Infrastructure
For example, “green” hydrogen generated through electrolysis from renewable electricity and water can be transported via the existing gas infrastructure, temporarily stored and then used in buildings as an energy supplier for CO2-free heating. As a result, hydrogen supports decarbonization and the implementation of global climate targets in the building sector.
Climate researchers and environmental experts as well as society and politics agree: The energy transition is crucial in order to limit climate change and the associated warming of the earth’s atmosphere. In addition, there is consensus that climate change as well as the resulting rise in sea levels and environmental disasters are caused by human activity. By burning fossil fuels for industry and mobility, to heat buildings, and especially to generate electricity, humans produce too much harmful carbon dioxide.
Renewable energies – essentially wind, hydroelectric and solar power – can be used to generate electricity in order to significantly reduce CO2 emissions and limit global warming to 1.5°C, as stipulated by the Paris Climate Agreement. At the same time, it is vital to reduce the absolute consumption of energy, for example by improving the efficiency of energy consumers. In building technology, energy savings of up to 30 percent are possible simply by replacing outdated heating systems with gas condensing boilers equipped with advanced control technology. In Europe, 60 percent of all heating equipment is obsolete.
To heat buildings, the industry is relying on heat pumps, which are powered by ambient heat (approximately 75 percent) and electricity (25 percent). However, upgrading to advanced heating systems will take many more years and it is not always easy to do accomplish, especially in existing buildings. In addition, there is not yet enough renewable electricity available for full-scale electrification of buildings and the transportation and industry sectors. And last but not least, power grids need to be expanded on a massive scale to achieve these goals.
Intermediate storage for renewable energy
At the October 2021 meeting of the G20 countries in Rome, the participants agreed that even more needs to be done for climate protection. However, with increasing use of wind and solar power to generate electricity, it is becoming increasingly difficult to balance the power grids between production and consumption. For this reason, energy storage is needed. One possibility for energy storage is the production of hydrogen. A certain amount of hydrogen can already be fed into the gas networks and used in heating systems as a mixture with natural gas.
A number of in-depth studies have shown that a 10 percent hydrogen content in natural gas will not cause problems for consumers. Most equipment is already able to handle 20 percent hydrogen. As a result, surplus electricity can be harnessed in a climate-neutral way using electrolysis systems to separate water into oxygen and hydrogen. Hydrogen can then be used via the existing gas infrastructure.
Initial pilot plants that work this way are already in operation. A pioneering plant for the production of “green” hydrogen is currently being built in the town of Wunsiedel in Bavaria’s Fichtel Mountains. With a capacity of 6 MW in the first expansion stage, it is one of the largest of its kind and serves as a model for all of Germany.
Thanks to its ability to handle changing mixing proportions, the use of hydrogen to heat buildings is one solution to balance the power grids. At the same time, it allows for an increasingly climate-friendly way to utilize existing gas consumption facilities.
The enormous potential of hydrogen
According to the “Hydrogen Roadmap” of the German industry association DVGW, it must be possible to increase the proportion of hydrogen in gas networks to 100 percent in order to achieve a climate-neutral future. However, further technical innovations as well as fundamental standardization changes are still required to convert all gas-consuming appliances. It goes without saying that in the short term hydrogen will not be available on a large scale to be fed into the gas network. But this approach holds great promise because of the possibility of ongoing expansion and the continued use of the existing infrastructure. This can be achieved by using gas consumption equipment that is “hydrogen-ready.”
In order to successfully implement the energy transition in the building sector, it is imperative to pursue a strategy that is open to all technologies. Hydrogen offers a unique opportunity to couple the various sectors, acting as both an energy storage medium and an energy carrier to heat buildings. To prepare for this, the gas heating equipment industry is adapting its technologies for the use of hydrogen.
