Elstor Storage in Selkäharju succesfully deployed

History of Selkäharju Elstor Storage

Elstor Thermal Energy Storage Selkäharju unit has a long and interesting history, as it is the company’s very first thermal storage facility. It was originally built as the first prototype for the Mustola district heating plant. The first prototype provided Elstor with a lot of valuable information about the functioning of the unit. The equipment was later upgraded to incorporate latest Elstor technology. At the same time, the equipment was transferred from Mustola to the Selkäharju district heating plant.

Experiences from the first heating season

At the Selkäharju district heating plant, the Elstor heat storage system, which replaces the use of natural gas, has produced over 850,000 kWh of district heat since November. The amount produced corresponds to the heat consumption of about 100 private houses. The use of the system over the last six months has resulted in a reduction of CO₂ emissions of around 140 tonnes in Selkäharju. This reduction is equivalent to the emissions produced by about 160 internal combustion engine cars over the same period (117 g,CO₂/km, 15 000 km/year).

Due to the trial period, most of the time the use of the device was limited to weekdays. In the future, Elstor production will also be used at weekends. The next heating season will therefore be even busier than the first.

During the first heating season, the average price of the electricity consumed by Elstor Thermal Storage has been about 5 cents/kWh. The average price of the charging hours has been on average about 26% below the average market price. The period under consideration during the first heating season also includes test periods for the commissioning of the installation, during which the charging hours have not been optimised. In the future, we can therefore expect an even lower unit price compared to market prices.

Elstor Storage in district heating

Elstor Thermal Storage is also well suited to provide additional flexibility capacity for district heating stand-alone networks. Here again, the benefits of the device are derived from the fully independent charging and discharging processes, which allow the use to be optimised not only according to hourly electricity prices, but also according to the reserve market. The high energy density storage structure of the Elstor system allows high charging and discharging capacities in relation to the storage capacity, supporting the participation in the reserve market.