Pit Thermal Energy Storage in Høje Taastrup | Denmark

VEKS (municipality owned heat transmission company) and HTF (consumer owned heat distribution company) has implemented a Pit Thermal Energy Storage (PTES) in Høje Taastrup, Denmark to provide flexibility to the electricity production system and the heat production system in Greater Copenhagen.

The project was developed 2017-2018 and implemented 2019-2022. During implementation material tests were carried out and new implementation methods were developed.

Size of the storage is 70,000 m3, storage medium is water, in- and outlet capacity is 30 MW and storage content is 3,300 MWh.

The project has several innovative elements, such as

  • It is the first PTES of it´s kind serving with flexibility and heated up to 90oC constantly.
  • A new business model had to be developed to integrate the storage in the heat and electricity production system in Greater Copenhagen.
  • A new developed polypropylene (PP)-membrane is implemented to resist higher water temperature. It is used for tightening of bottom and sides and for floating membrane under the lid. Implementation methods for membranes had to be modified further because the membrane is vulnerable to low temperatures.
  • In- and outlet system and lid have innovative elements

The storage serves four CHP plants and three waste-to-energy plants. Optimization of electricity production (sector coupling) and saved peak production result in 27.4 TJ saved fuel/year and a total CO2-reduction of 6,200 tons/year.

The total investment is 10.7 Mio €. Simple payback period is 12 years and IRR is 7.5%.

The PTES is commissioned end of December 2022 and in commercial operation from 15th February 2023.


Visit the project’s website here.

Download the project’s brochure here.