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A circular by design environmentally friendly geothermal energy solution based on a horizontal closed loop - HOCLOOP

Project description

Facilitating the extraction of heat from deep or shallow formation rocks

Below the Earth’s surface, there’s a powerful and reliable source of renewable energy that can significantly contribute to solving our energy problems. Just 0.1 % of Earth’s total heat content could meet our energy needs for over 1 million years. While geothermal energy is not new, it remains limited to particular regions, representing less than 1 % of the global energy production. The conventional technology relies primarily on scarce hot permeable aquifers to extract heat. To address this challenge, the EU-funded HOCLOOP project will use a horizontal closed-loop solution combined with innovative CO2-based heat carrier fluids to extract geothermal energy from deep or shallow formation rocks. HOCLOOP’s solution will facilitate the sustainable exploitation of geothermal sources in new regions.


Geothermal energy has a large potential as a clean renewable energy source. The conventional technology is mainly based on heat extraction from hot permeable aquifers. Such aquifers are hard to find, limit the applications and imply high cost and risks. The proposed project aims to mitigate this challenge.

The idea is to use an innovative horizontal closed loop solution for the extraction of heat from deep or shallow formation rocks. The solution is based on new drilling technology and solves the challenges of conventional construction of geothermal wells. The solution will improve the power production due to extended reach horizontal drilling with a large hole size. Further improvement is expected to be achieved by use of alternative circulation fluids to water, such as CO2 based fluids. It is expected that the solution can reduce the LCOE compared to the conventional solution and meet the SET plan targets.

The project will develop the tools to enable the proposed geothermal solution and demonstrate the technology in a full-scale test operation to TRL5. The work will cover the development and validation of models for the heat flow and investigate the possibility for improving the electricity production by using alternative fluids to water. The work will also cover the investigation of potential EU pilot sites, environmental assessment, and the social acceptance.

It is expected that the solution will enable exploitation of geothermal energy sources in new regions with- or without good hydrothermal reservoirs. The solution is foreseen to be integrated with other renewables to improve the reliability of the power supply and grid stability, and to be applicable to a variety of geological conditions. It is also expected to solve the main issues of geothermal energy related to emissions, seismicity, and environmental aspects.

9 partners from 6 European countries with complementary expertise join forces for this 42 months project.



Net EU contribution
€ 879 447,00
Instituttv 18
2007 Kjeller

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Norge Oslo og Viken Viken
Activity type
Research Organisations
Other funding
€ 0,00

Participants (8)