SMARTrenew partner, Oulu University of Applied Sciences, piloting district heating, heat storage solution in Finland

Under project SMARTrenew, Oulu University of Applied Sciences, together with Evo, is piloting a major heat storage solution for district heating in Kuusamo, Finland with the installation of a 500m3 heat storage tank.

EVO is the water and energy co-operative that is responsible for district heating, water treatment and clean water distribution in Kuusamo. In the downtown area, the district heating is produced at the Toranki CHP plant and in the Ruka area at the Ruka biopower plant.

When the CHP and biopower plants cannot generate enough heat to cover the needs of the entire customer base, EVO needs to use its oil burning, auxiliary, heat-only boilers to generate the needed additional heat. To solve this problem, EVO, in cooperation with Oulu University of Applied Sciences, under SMARTrenew, is building a 500m3 heat storage to be connected to the district heating network. Utilizing this heat storage solution, EVO could reduce its need to use oil for additional heating.

In the current district heating system in Kuusamo, the main plant produces the required heat using mainly wood based fuel. During very cold weather the heat production from the main plant is not enough to match the heat demands and auxiliary systems are being used. The auxiliary systems are operated with oil based fuel. The SMARTrenew pilot aims to replace auxiliary oil systems with renewable, heat storage solutions. 

Energy Consumption, Efficiency, Cost Before Installation:

Energy consumption is dependent on the clients of the district heating network. Kuusamo, situated in northern Ostrobothnia, in north east Finland has a population of over 15,000 people. Ruka, the second biggest ski destination in Finland, is situated in Kuusamo creating its own share of heating demand.

Smart Energy/Heat Storage Innovation:

A calculator is being developed to help optimize usage of the heat storage. The calculator tool “predicts” hourly power demands by the network along with the highest peaks in power demand. This data can then be used by the operator to optimize the use of the storage. The calculator has been presented to the pilot partner and is waiting for the next step in development to integrate with their systems. The calculator brings a “smart component” to the heat storage.

Energy/Heat Consumption After Pilot Installation:

Pilot installation won’t affect energy consumption/demand. The goal of the pilot is to shift the current oil fueled energy production into energy produced by renewable fuels. A student project group made calculations based on EVO energy production history.

In July 2019, the CHP plant in Kuusamo produced 365 MWh heat energy with oil-based fuel, of which 222 MWh could have been covered with the use of the planned heat storage solution. If one MWh of oil costs approximately 85 euros and renewable fuels used in CHP plant cost approximately 22 euros per MWh the heat storage could have saved EVO almost 14,000 euros in July alone. Such heating storage system brings significant gains both financially and environmentally since using renewable fuel is considered CO2 free.

Heat storage system also functions as a backup in case of power plant or pipeline failures thus making the district heating network more stable. The heat storage also functions as “customer” for the CHP at times when electricity market prices are high.

Alternatively Comparison with Similar Buildings or Scenarios:

Kuopion Energia, an energy company in Kuopio has stated that their heat storage system brought them 1 million euros worth of savings in its first year of operation. Their heat storage is significantly bigger but functions similarly and has many synergies with the SMARTrenew Kuusamo pilot.