Green Therma has awarded Helmerich & Payne (H&P), the world's largest onshore drilling contractor, the drilling rig contract for its Heat4Ever demonstration project in Aalborg, Denmark. H&P Rig T203 has been selected to drill what will be Denmark's deepest and longest geothermal well, with spudding targeted for January 2027.
The well is planned to reach approximately 4 km vertical depth, followed by a horizontal section of around 3 km. The EUDP-backed Aalborg project is being developed in collaboration with Aalborg Forsyning as heat off-taker and will demonstrate Green Therma's Heat4Ever solution at full scale, paving the way for 30 years of geothermal district heating for delivery to Aalborg.
A different approach to geothermal heat
Heat4Ever represents a fundamentally different approach to geothermal heat. Unlike conventional hydrothermal systems, which depend on suitable underground water-bearing reservoirs and bring naturally occurring hot geothermal water to the surface to extract its heat, Heat4Ever is a closed-loop system. A fluid circulates within the sealed well system, absorbing heat directly from the surrounding subsurface and carrying that heat to the surface. This removes the dependency on a productive geothermal water reservoir and reduces several of the geological and operational risks and limitations associated with conventional geothermal development.
Green Therma's DualVac insulated pipe technology is designed to minimize heat loss as the fluid returns to the surface, enabling the heat to be delivered at a temperature suitable for direct use, with electricity primarily required to circulate the fluid.
The approach is designed to make deep geothermal heat more predictable and scalable across locations where sufficient heat demand exists, serving both district heating networks and industrial heat users. As a local, renewable heat resource available around the clock, geothermal can also complement weather-dependent renewable energy sources in the broader energy mix.
"We've been designing the Heat4Ever solution as a full-scale product with one clear ambition: to make deep geothermal energy scalable and commercially viable wherever heat is needed. Selecting the drilling rig partner for Aalborg turns that ambition into reality. We're delighted to have H&P alongside us as we prepare to drill what will be Denmark's deepest geothermal well," said Jørgen Peter Rasmussen, CEO and Founder, Green Therma.
H&P will provide Rig T203, along with its experienced drilling team and operational expertise, to execute the well safely and efficiently. For H&P, the project represents the next step toward delivering one of Denmark's most ambitious geothermal wells.
"Drilling a well of this depth requires the right people, the right rig and the right execution. This project is exactly the kind of technically demanding challenge where H&P can make a real difference, and we're pleased to continue our collaboration with Green Therma as we work together to demonstrate the potential of deep geothermal energy," said John Bell, Executive Vice President, International Land, H&P.
From demonstration to scalable renewable heat
Delivering the well safely, on time and on budget will be an important step in demonstrating Heat4Ever at full scale and moving the solution toward commercial deployment in Denmark and internationally. For Green Therma, having an experienced drilling partner such as H&P is critical to successfully executing our first full-scale project of this technical complexity.
Drilling preparations are underway, with spudding planned for January 2027.
Further information
More information about Green Therma and the Aalborg Heat4Ever demonstration project:
