PlanEnergi is main consultant for a 70,000 m³ pit heat thermal storage (PTES) project where the PTES will be demonstrated in a new function as accumulation tank in a district heating (DH) system with combined heat and power (CHP) from biomass and waste incineration. The energy content of the PTES will be 3,300 MWh. The use of the PTES means that energy production will increase on CHP and incineration plants and there will be an optimization towards the electricity price. The electricity price varies, with the variation in wind and solar-based electricity production, but also with the hydropower production in the countries around DK. In hours with high renewable electricity production, electricity prices are low, and the PTES must cause electricity and heat production to be transferred to plants with relatively low electricity production and vice versa. Furthermore, heat peak load production will be replaced by discharge from PTES. In the future, heat production will be transferred to electricity-consuming technologies, such as large electric-powered heat pumps for district heating, in hours where the electricity price are relatively low.
The PTES will be owned 50% by VEKS and 50% by Høje Taastrup district heating company.
The project is supported by the Danish research and development program EUDP.
Purpose of the project
The PTES will be demonstrated in Høje Taastrup DH Company’s distribution system but connected to the
large VEKS´ transmission system as part of the integrated DH system in Greater Copenhagen. This makes it possible for all the CHP plants in the transmission systems of VEKS and CTR to interact with the storage.
The purpose of the project is fourfold:
- To develop and demonstrate a PTES that can be operated in a more flexible and advanced way than
has been seen to date. Thus, allowing charge and discharge of energy at a daily and weekly basis
allowing flexible electricity production from CHP plants and peak shaving in large DH systems.
- To develop and demonstrate new innovative technical solutions that can solve some of the necessary challenges needed to bring the PTES technology an important step further towards fully commercial scale used as accumulation tank in large DH systems. One of these solutions is to use a new developed PP-membrane produced by AGRU in Austria
- To demonstrate, that the PTES can replace a similar steel tank and be implemented for less than 1/3
of the costs for a steel tank. The price for the PTES is expected to be 300 DKK/m³ (40 €/m³) compared with app. 1,000 DKK/m³ (133 €/m³) for a steel tank with the same capacity. In addition, costs for connections to the district heating network and pumps must be added for both the PTES and the steel tank.
- To develop an optimization system for a PTES in a large DH system with a large number
of stakeholders (heat producers and consumers).
Implementation of the demonstration project is ongoing. The PTES has been filled with water (district heating quality) during winter and lid construction has started. Expected finalization 31. December 2022.
Further information: Heat pit storage_folder 2022_uk