Geothermal Driven Concrete Energy Pile Joints

Geothermal energy is a well-known and well-established energy source. Unfortunately, it is also an underutilized energy source to date, despite its enormous potential. It is estimated that the amount of energy available within 10,000 m of the earth’s surface is up to 50,000 times greater than all the world’s hydrocarbon reserves (Shere, 2013). This represents a massive, untapped market with great economic and environmental opportunities. This project, in collaboration with leading industry partners on pile joints and pile production, has developed, verified and tested in practice a new pile joint that makes it possible to utilize geothermal energy from precast concrete piles. Until now, no one has managed to make such a pile joint without compromising the load-bearing capacity of the pre-fabricated piles. Tests carried out in accordance with industry standard EN 12794:2005 (A1:2007 Annex A) have shown that the pile joint we have developed meets the same standard requirements as traditional pile joints and that the piles also have the same load-bearing capacity. The pile joint has thus met all the requirements for CE marking and is ready for production in its current state, and we're in discussion with several building companies that are eager to run a pilot test of the concept. To test the effect we can extract from piles produced with DEP Joint, we have driven two piles of two segments each down to the bedrock at a test site at Dragvoll. These are instrumented for detailed measurements of the capacity of the piles over time. Theoretical calculations estimate that one can harvest 60-70% of the energy demand for heating and cooling in buildings from the piles. he results from the field trial will be published at a later stage after the conclusion of this project.

We have successfully demonstrated that it is feasible to exploit geothermal energy from pre-cast concrete piles without compromising on the bearing capacity of the piles. After several iterations of the design of the DEP Joint, we now have a functional prototype that has been tested according to the industry standards (EN 12794:2005) and passed these with similar performance as standard pile joints. This opens up a new business segment for both pile joints producers, pile producers and producers with vertical integration of both joints and piles, which has the potential to significantly reduce the energy needed for heating and cooling of buildings at a very low fractional cost. Furthermore, widespread use of energy piles will reduce the electricity grid load and reduce CO2 emissions and help us move towards a greener future.