The aim of the project was to reduce emissions in heat production through the introduction of a new thermal storage technology. The storage unit is charged with cost-effective and low-emission electricity, and the heat is stored in a storage module. Heat is then discharged from the battery into the district heating network as needed, reducing the use of natural gas and fuel oil in district heating production.
An additional benefit is that the energy storage can also be used for frequency regulation of the power grid, demand response, and on the balancing power market. This energy storage solution thus also enables a higher share of renewable, variable electricity generation in the grid.
As part of the project, an innovative heat battery using new technology was installed in the district heating network in the Selkäharju area. The Selkäharju area operates with a separate district heating network, where heat has previously been produced at a heating plant using natural gas.
Cost and emissions reductions with heat storage
The introduction of the heat battery is expected to reduce CO2 emissions in the Selkäharju district heating network by 300–400 tonnes of CO2 equivalent per year, depending on electricity prices. In addition, the solution is expected to reduce heat production costs compared to previous methods. Maintenance costs are also anticipated to be lower than those of a traditional heating boiler.
Time frame
The industrial-scale pilot project for thermal storage began in late 2019 within the Mustola district heating network. The thermal storage unit was installed at the Mustola heating plant in summer 2020, and its performance was tested and evaluated in 2021–2022. At the request of Lappeenranta Energy, the equipment was relocated to the Selkäharju district heating network during upgrade works in 2023. In its first six months in the Selkäharju district heating network, the unit achieved emission reductions of 160 tonnes CO2 equivalent.
Current
More information
- Director Ilkka Räsänen, City of Lappeenranta, firstname.lastname@lappeenranta.fi, tel. +358 400 815 284
- Climate coordinator Petri Kero, City of Lappeenranta, firstname.lastname@lappeenranta.fi, tel. +358 40 6530 508