5%
Process heat Businesses
surplus heat
16%
Direct utilization of waste heat is difficult
79%
Process heat Businesses
surplus heat
District heating
Revenue from district heating Extra hydrogen revenue Original hydrogen revenue
Utilization of waste heat
Green district heating replace fossil-based process heat
Figure 2: Revenue for 20 MW electrolysis plant with a DH connection. In the report, the surplus heat at (70° C) is valued at 27 EUR/MWh during the winter and 20 EUR/MWh during the summer, whereas the surplus heat at 35° C is valued at 2 EUR/MWh in the analyses. The additional hydrogen revenue results from extra operating hours due to the DH revenue. Assumptions are described in the report.
Figure 3: The business sector needs green alternatives to replace fossil process heat. The report explains why surplus heat from PtX needs access to a DH system. Direct utilization for industrial processes and heating is difficult (top), whereas the integration can be made possible with district heating (bottom).
PtX plants require planning and cooperation, and potential use of surplus heat should be included as early as possible in the process. Improving the business case for green hydrogen The surplus heat from hydrogen production can contribute to the business case of electrolysis. If connected to a DH sys- tem, the heat has value and can be sold to generate revenue. The electricity price primarily sets The number of operating hours for the hydrogen plant is primarily set by the electricity price. Therefore, the revenue from the surplus heat is the ad- ditional effect of increasing the limit for when electricity prices become too high for hydrogen production. Figure 2 shows an example of the impact on the revenue of a hydrogen plant connected to a DH system. District heating welcomes heat from Power-to-X The heat from PtX is well suited for integration into a carbon- neutral DH system. It could be a valuable green heat source with high temperatures, large volumes, and a high number of operating hours. This is why all the central DH systems in Den- mark are investigating the possibilities for connecting to future PtX facilities. It is expected that all strategic energy plans and heat plans in these areas will discuss integration of PtX and DH. A DH system will have several heat sources, and the value of the heat for PtX will depend on the other heat sources in the system. In the summer, heat is abundant and cheap, so the hydrogen plant will experience lower prices than during winter peak load. Other types of heat production may also depend on the electricity price. This means that the revenue of the surplus heat will vary hour-by-hour and season-by-season — some- thing to include in the business case considerations. Integrating heat and hydrogen benefits other sectors PtX heat for DH promotes integration across sectors such as power, heating, transport, waste, industry, and agriculture. The results of this are increased energy efficiency, lower costs, and new possibilities.
Direct electrification is one option, but if available, DH is often a competitive alternative. Figure 3 illustrates how waste heat from PtX can substitute fossil-based heat used in the industry if the heating infrastructure is or becomes available. This type of synergies is already known and used in Denmark, where WtE plants and DH systems are closely coupled and shows the power and potential of sector integration.
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THE RECOMMENDATIONS IN THE REPORT ARE GROUPED INTO FOUR TOPICS • The value of integrating DH and PtX is overlooked • Investments in energy infrastructure are needed • Development and demonstration – including a list of what is needed • Planning, timing, and framework conditions}
An example of this is the challenges faced by industrial sites needing to convert from fossil-based to green process heat.
For further information please contact: Hanne Kortegaard Støchkel, HKS@dbdh.dk
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