There is a broad consensus that the heat from power-to-X (PtX) can be used in district heating, but there has been no overview or concrete definition of the advantages of integrating PtX and district heating. This report focuses on the role of district heating in relation to PtX, and why integrating PtX and district heating is important. It focuses on the production of hydrogen (electrolysis), as electrolysis is part of all PtX chains and much waste heat is generated at this stage.
It is uncertain where and when PtX plants will be constructed in Denmark and how large their capacity will be. Hydrogen is absolutely central, and total capacity estimates for 2030 are from 1 to 6 GW electrolysis. Waste heat is generated both from the electrolysis itself and by the auxiliary systems in the PtX plant, such as compressors. Waste heat makes up around 10-25 % of the energy and could potentially cover up to around 20 % of current district heating production at a capacity of 6 GW.
The report concludes:
- District heating can contribute to the success of PtX. The production costs of green hydrogen can be reduced if electrolysis and district heating are linked together. The financial improvements for hydrogen producers can help to accelerate the construction of larger PtX plants in Denmark.
- Heat from PtX is well suited for integration into district heating as part of a carbon-neutral district heating supply.
- The use of PtX heat for district heating promotes integration across sectors such as power, heating, transport, waste, industry and agriculture. Integration with district heating means increased energy e¡ciency and sectoral integration.
- It could also mean increased green exports, if the Danish PtX strategy is designed in conjunction with Danish strengths such as wind power and district heating.