Demonstration of pit heat thermal storage in large scale CHP based district heating system as a part of a flexible energy system

Project description

In the FLEX_TES project a 70,000 m3 pit heat thermal storage (PTES) will be demonstrated in a new function as accumulation tank in a district heating system with CHP from incineration and biomass. This will increase the flexibility and capacity value of CHP plants in the electricity market. Also expensive peak production in the heat market can be replaced by heat discharge from the PTES.

The storage will be demonstrated in Høje Taastrup Fjernvarmes distribution system but connected to the large VEKS´ transmission system as part of the integrated District Heating system in Greater Copenhagen. This makes it possible for all the CHP plants in the transmission systems of VEKS, CTR and Vestforbrænding to interact with the storage.

International collaborations:
The project will be carried out in close collaboration between Department of Civil Engineering, Technical University of Denmark and Vestegnens Kraftvarmeselsskab I/S, Høje Taastrup Fjernvarme a.m.b.a., PlanEnergi, Ea Energy Analyses.

Implementation of the demonstration project will open a new huge market for PTES as a viable tool for DH systems to be effective integrators of fluctuating renewables. It will be demonstrated that the temperature in the upper part of the storage can be constantly fixed at 90°C making pit storages able to replace the more expensive steel tanks. The objective is to make this possible by change of liner, insulation materials and design. Also it will be demonstrated how advanced operation creates synergy between heat and electricity markets. The price for the storage is expected to be less than 1/3 of the price for similar steel tanks
A comprehensive monitoring program is part of the project.