Lounavoima power plant uses QHeat heat storage technology to achieve exceptional energy efficiency in district heating

QHeat provided a geothermal energy system technology to Lounavoima, an energy company in Southwest Finland. The collaboration aimed to help Lounavoima waste-to-energy power plant achieve better energy efficiency and store excess heat gathered in warm seasons.

6
X

deep coaxial heat wells finalised and working by the end of 2025

8-14
GWh

energy produced annually depending on winter temperatures

6
MW

peak capacity for district heating derived from heat storage


Challenge

Founded in 2017, Lounavoima’s main task is to recover municipal waste that cannot be recycled by the local waste management company, Lounais-Suomen Jätehuolto, into district heating and electricity. Their Korvenmäki waste-to-energy power plant produces around 220 GWh of heating energy from municipal waste each year. Using municipal waste for heating energy is an effective way to reduce greenhouse gas emissions in both waste management and energy production. With the commissioning of the Korvenmäki power plant, which replaces fossil fuels and peat with waste fuel, Salo's district heating carbon dioxide emissions were halved.

However, the plant’s efficiency has been seasonal: during the warmer months, the plant generates a significant surplus of heat. Annually, about a quarter of this is lost as waste heat. During hours of peak energy consumption, the waste-to-energy plant cannot supply enough energy and must be complemented with energy from fossil fuels and biomass. Since this contributes to the power plant’s CO2 emissions, it does not serve as a long-term strategy for Lounavoima—the company is dedicated to being a forerunner in the circular economy and achieving the most efficient energy production.

Solution

In collaboration with QHeat, Lounavoima decided in 2019 to commission a geothermal energy system consisting of six deep coaxial heat wells. These wells help Lounavoima store the surplus heat energy the power plant generates during the summer and utilize it during the heating season.

The system also allows Salo’s district heating company to replace fossil-based peak energy production with stored energy, reducing emissions and costs. The system extracts maximum efficiency from stored heat, temporarily cooling the well during high-demand periods when energy is usually at its most expensive and carbon-intensive.

Heat production from the storage facility is always initiated first if the district heating capacity produced by the waste-to-energy plant is insufficient. In these situations, the system primarily prevents the activation of fossil-fuel-based peak energy production and backup power plants.

Results

At the end of 2024, five of the intended six wells have been installed and two of them are in full operation. All wells should be finalised and working by the end of 2025. The real-life trials have validated the expected results.

“Each watt-hour generated from stored energy holds value. We’ve managed to validate the potential of these wells and are already seeing a return on our investment.”

- Petri Onikki, Managing Director of Lounavoima

Impact

The Lounavoima geothermal energy system is one of a kind in Finland and paves the way for the future of efficient and ecological energy storage at power plants. Within the next five years, the facility will offer efficient and cost-effective heating to the residents of Salo district and will help prevent unpredictable price increases during peak heating seasons. The Lounavoima geothermal energy system has attracted significant international interest and can inspire other energy producers who want to minimize waste energy and cut down on fossil-fuel-based heating.

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