We secure our power production capacity by obtaining peak and reserve capacity from the local industry and trough on-demand capacity of our own auxiliary heating plants. The proportion of peak and reserve capacity of our total annual heat power capacity is approximately 10%.
Local industrial facilities produce district heat power in co-generation plants using wood and peat. When needed, we can also produce heat and reserve capacity in our own oil-fired auxiliary heating plants with total capacity of approximately 210 megawatts. The auxiliary heating plants are located in various parts of the city: in Limingantulli, Vasaraperä, Pateniemi, Oulunsuu and Laanila. The Toppila power plant also has two oil-fired peak and reserve units with combined power of 90 megawatts.
We also have a bedrock heat storage system that is used for optimisation of energy sourcing and as a spare heat supply. In 1996, we repurposed a bedrock industrial gasoline storage of 190,000 m³ in the Kemira industrial park into a heat accumulator. The capacity of the accumulator is 10 gigawatt-hours, and it can be charged or discharged at a rate of 80 megawatts.