Heat stored in 2,000-meter-deep geothermal wells in Salo – Construction of three new geothermal wells already underway
Press release 2 July 2024
A geothermal heat well storage has been commissioned at Lounavoima’s Waste-to-Energy (WtE) plant at the Lounapuisto circular economy park in Salo. The test run results for the first well have been good, and a decision has been made to construct three additional wells. Upon completion of the project, the WtE plant will have six geothermal heat wells with a combined output of 6MW. Waste heat produced by the WtE plant is stored in the geothermal heat wells and used for district heating in the winter.
The first phase of the geothermal heat wells constructed at Lounavoima’s Waste-to-Energy (WtE) plant has been successfully completed. The first 1,600-metre-deep well was tested last winter. The well produced 450 MWh of energy from January to March. Waste heat produced by the WtE plant is stored in the geothermal heat wells and used for district heating in the winter. So next winter, homes in Salo will be heated with heat stored more than 2 km underground.
A second heat well was drilled in the autumn of 2023 and a third was drilled in the winter of 2024. The second well is currently being tested and the pipework for the third well will be completed in the late summer. The wells reached their target depths of 2,000 metres.
A decision was made in June 2024 to invest in a third phase, which involves the construction of three additional wells. Construction work has already begun, and completion of the final heat well is expected by the summer of 2025. The project will then be fully completed.
Reduces carbon dioxide emissions produced by district heating production
Upon their completion, the six new geothermal heat wells will have a combined output of as much as 14 GWh a year, which is equivalent to the annual heating need of approximately 700 single-family homes. The project will have a significant impact on the production structure of district heating company Salon Kaukolämpö and reduces carbon dioxide emissions produced by district heating production.
“The heat well production will always be used first if the district heat output of the WtE plant isn’t enough. This allows us to primarily replace the need for starting oil heating plants and, in many cases, we can also avoid the need to start a backup power plant,” explains Lounavoima and Salon Kaukolämpö Managing Director Petri Onikki.
The geothermal heat well project has been carried out in cooperation with innovative Finnish companies. Medium-deep heat well technology developer Quantitative Heat Oy (QHeat) has carried out other geothermal heat projects in Finland, but the Lounavoima geothermal heat storage is the first of its kind.
“We have such top expertise here in Finland. Even though the new technology development project has not always gone smoothly, the results have exceeded our expectations. The geothermal heat wells have a multiplying effect on heat production in Salo,” says Onikki.
The heat wells were drilled using new drilling equipment developed by Finnish company Geomachine Oy for the project. This equipment made it possible to reach the target depth of 2,000 metres. Finnish company Calefa Oy delivered the heat pump process for the heat wells.
“Lounavoima and the project funders have turned the testing and development of Finnish expertise in the project into an international export product. The project is of great interest to the energy sector because its result is cost-effective seasonal thermal energy storage (STES),” explains QHeat CEO Erika Salmenvaara.
Concrete circular economy work at the Lounapuisto circular economy park
The decision to invest in the first phase of the geothermal well project was made in the early autumn of 2020, and in the second phase in early 2023. For Lounavoima and its owners, the project is a major new technology venture, whose goal is to increase the reuse of waste and make use of the energy it produces for district heating in Salo. Lounavoima is located in the Lounapuisto circular economy park, which is also the site of the project launched last year.
“The project is a successful example of concrete circular economy work at Lounapuisto,” says Onikki.
The primary funder of the project is Salon Kaukolämpö Oy, which will gain a significant boost in environmentally-friendly energy for its own operations. The EUR 3 million in energy support granted by the Ministry of Economic Affairs and Employment kickstarted the project.
A press conference was held at 10:00 a.m. on Tuesday, 2 July at Lounavoima to discuss the project. Minister of Climate and the Environment Kai Mykkänen spoke at the event.