Utilising geodata for enhancing success rate of geothermal projects in Finland

Shallow geothermal wells for heating individual houses have been utilised successfully in Finland for decades. Recently, deep geothermal wells (down to six kilometres) and medium deep wells (500–3 000 metres) have been piloted for district heating, regional-scale applications in urban areas, and industrial building heating, with varying degrees of success.

Bedrock in Finland consists mostly of Precambrian crystalline rocks. Ancient bedrock is cold and fractured. Several geothermal projects have been delayed, shortened or even cancelled due to challenges in drilling or insufficient heat production. In Geoenergialoikka (Geoenergy Leap) project, the Geological Survey of Finland (GTK) has been developing a workflow to integrate geodata for the site selection of medium deep geothermal wells and consequently for estimating heat production, aiming to improve the success rate of geothermal projects.  

The workflow has been developed while planning and implementing three medium deep geothermal wells (600–800 m) in Kotka, Oulu and Kokkola. Existing geodata has been utilised to determine the locations of the proposed geothermal wells and to assess drilling risks. The datasets include geodata available from GTK’s Hakku service, e.g. geological and aerogeophysical maps, Lidar and lineament data, as well as site specific geophysical survey data.  The cost-effectiveness of different data analyses and survey methods has been evaluated, and best practices for utilizing geodata in medium deep geothermal projects will be proposed.

Geoenergialoikka is co-funded by the European Union’s Just Transition Fund (JTF), the councils of Central Ostrobothnia, North Ostrobothnia, and Kymenlaakso, and the project partners: Geological Survey of Finland GTK (the coordinator), Centria University of Applied Sciences, Oulu University of Applied Sciences OAMK, University of Oulu, and South-Eastern Finland University of Applied Sciences XAMK. The project aims to speed up the comprehensive use of geothermal energy, strengthening national energy self-sufficiency and supply security, and impacting regional employment positively.