St1's Otaniemi geothermal heating plant pilot project investigates heat production methods

The pilot project of St1's Otaniemi geothermal heating plant explores the technical implementation options for the heating plant. The Engineered Geothermal System (EGS) technology, which was originally planned, has proved to be very challenging from a techno-economic point of view, and the current mapping phase aims to define the connection of the boreholes and above-the-ground production technologies to achieve the best possible thermal output.

During the design phase of the cross-flow test scheduled for fall 2021, detailed data from 2018 and 2020 stimulations  were analyzed to provide information on the water flows in the deep bedrock fractures and how it can be intensified if necessary. As a result of the analysis, it was concluded that the new cross-flow test between wells does not provide any additional information that would support to run the test and the time spent on it.

Geothermal technologies are converging

An important sub-goal of St1's Otaniemi geothermal heating plant pilot project has been to develop and test technically and economically viable solutions for all work phases of the geothermal business concept. The pilot project has provided valuable information on the conditions under which future projects must be evaluated. In recent years, heat pump technology has developed by leaps and bounds, enabling to reach sufficiently high temperatures in geothermal heat plants already with shallower heat well solutions. Advanced geothermal power plants will play an important role in the transition to zero-emission heat production, and St1 will utilize the lessons learned from the Otaniemi project in the following geothermal projects.

“The Otaniemi project has been started with the awareness that there are significant uncertainties in the project that could not have been verified without the work that has now been done. However, the goal was already at the time that the project would enable the company to acquire a significant amount of new know-how and at the same time develop geothermal heat production technology towards a technically and economically viable industrial-scale concept - here we are well advanced. We have a strong view that the production of heat by combustion should be minimized when geothermal heat and heat pump technology allow for a sustainably produced alternative, ”says Matti Pentti, Director of St1's Heat from the Ground unit.

More information:

St1 Oy, Matti Pentti, Director, Heat from the Ground, tel. +358 10557 4119,

St1 Nordic Oy is a Nordic energy Group whose vision is to be the leading producer and seller of CO2-aware energy. The Group researches and develops economically viable, environmentally sustainable energy solutions. St1 focuses on fuels marketing activities, oil refining and renewable energy solutions such as waste-based advanced ethanol fuels and industrial wind power. The Group has 1.250 St1 and Shell branded retail stations in Finland, Sweden and Norway. Headquartered in Helsinki, St1 employs currently more than 1.000 people.


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