Hydrogen in districts
Hydrogen is a central element of the energy transition and also interesting for district energy solutions, especially to increase the degree of self-sufficiency.
Hydrogen as energy storage
Hydrogen plays an important role in the energy transition because it allows surplus electricity from renewable energy sources to be stored temporarily and used at times when the energy supply is lower. In this way, a hybrid energy supply and storage is achieved. To store energy over short periods of time, batteries are an economical solution. However, if electricity is to be stored for days, weeks or even months, hydrogen is a promising solution. Hydrogen-based systems are also interesting for district energy systems. Surplus electricity from photovoltaic systems can be partially converted into hydrogen during the midday hours. An electrolyzer is used in the district's energy hub for this purpose. It splits water into oxygen and hydrogen. The hydrogen is compressed and fed into hydrogen storage tanks. If the renewable electricity from the photovoltaic or wind power plants is not sufficient to supply the district with electricity, hydrogen is taken from the storage tank and converted back into electricity in a fuel cell. Depending on the technical design of the fuel cell, this also generates waste heat that can be fed into district heating networks.
Hydrogen for mobility
Especially for district energy systems, mobility is also an important element. If there is a relevant hydrogen demand for hydrogen-powered vehicles, surplus hydrogen can also be used for this purpose.
Feed-in of hydrogen into the natural gas grid
If large amounts of renewable electricity are available, a hydrogen system can be used to significantly increase the degree of self-sufficiency rate of the district and to use the existing local energy resources on site. Surplus hydrogen can also be partially fed into the local natural gas grid. This is possible up to a hydrogen content of about 5 - 10 % in the natural gas grid.