This article appeared in gwf Gas+ Energie Magazin August 11, 2025, (it has been translated from German).
gwf: Mr. Land, Eavor is a relatively young company. What should we know about it?
Alexander Land: Eavor Technologies Inc. has been in existence since 2017. The founders' question was: How can conventional drilling methods from the oil and gas industry be sustainably used for deep geothermal energy? This consideration gave rise to the idea of connecting wells underground, as we are now doing with the Eavor-Loop™. The German subsidiary was founded in 2019, is based in Düsseldorf, and is the parent company's operational project arm for the European market.
gwf: You mentioned the Eavor Loop. What is that?
Land: The Eavor Loop™ is our product – the only one we offer. It consists of two vertical boreholes that fan out into several horizontal boreholes at a flexibly selectable depth, two of which are connected to form a loop. The target depth depends heavily on the location. It is important that the heat-conducting rock layer is reached. In Geretsried, we went down to a depth of about 4,500 m. Here, the temperature of the heat-conducting rock layer is around 160°C. Once the target depth is reached at both points, we drill horizontally at each point – we guide the drills from the vertical boreholes at an almost right angle (in Geretsried: 88.5 degrees) to the side. These horizontal boreholes or "laterals" are then connected in pairs. This creates a loop. This process is repeated several times. We then introduce water into the resulting loops once, which absorbs the geothermal energy from the surrounding rock.
gwf: What diameter do the individual boreholes have?
Land: At the surface, we start with about 60 cm. The vertical boreholes then taper downwards like a telescope – you can imagine them like an upside-down car antenna. At their deepest point, the boreholes are only about 20 cm wide. The final lateral boreholes are roughly the diameter of an A4 sheet of paper before they are connected to form a loop.
gwf: How many loops does a single Eavor loop comprise, and how long is it in total?
Land: A loop consists of two vertical bores, called "stem bores," and twelve loops, for a total of 24 lateral bores. This can vary, however. In Geretsried, we are drilling four loops with a total length of approximately 320 km that is, 80 km per loop.
gwf: How do you make this system ready for use after drilling?
Land: The stem bores are stabilized by inserting steel pipes and then cementing the space between the steel pipes and the rock. We use conventional methods from the oil and gas industry. However, Eavor has developed its own patent for horizontal drilling: "Rock-Pipe™." This is a formulation approved by the authorities that is introduced into the system and seals the horizontally drilled rock surface.
gwf: Why is this step necessary?
Land: The goal is that the water, which we introduce as a working medium, cannot diffuse into the rock, but also that nothing from the rock penetrates into the closed circuit. In contrast to traditional geothermal energy, we do not drill for aquifers, i.e., underground warm water deposits, but for warm rock formations. Therefore, our approach is rightly called "reservoir-independent." Once the system is complete, we introduce drinking water as a carrier medium. The water flows downwards, absorbs the heat from the surrounding rock via the loops, and is then drawn upwards in a heated state via the so-called thermosiphon effect. So, once the water is moving in the closed system, we don't need pumps to draw it back up. Cold water is heavier than warm water – just normal physics.
gwf: So the water stays in the system permanently?
Land: Yes, it's added once and always stays the same. I hesitate to use the term perpetual motion, but once the cycle is set in motion, it moves on its own for decades. The systems are designed for a 30-year operating life – that has to do with depreciation. However, calculations show that an Eavor-Loop™ can run for up to 100 years without any problems.
gwf: What role does corrosion protection play in this?
Land: Corrosion protection is essential for us, as the steel pipes in the vertical boreholes have to withstand the extreme subsurface conditions for decades. We rely on a two-stage system: First, we have developed special electrodes that continuously monitor the condition of the metal components and measure whether and where corrosion is occurring. Second, special inhibitors are added to the working fluid – additives that form a protective layer on the metal surfaces or neutralize corrosive substances in the water. While we invest a great deal of development work in the innovative aspects of our technology, we rely on proven standards of the oil and gas industry for aspects such as corrosion protection.
gwf: How exactly does the heat supply work?
Land: In Geretsried, the water is still about 120°C hot when it reaches the top – a very good temperature for district heating or power generation. A heat exchanger installed on the surface absorbs some of this heat. The heat is either transferred to the district heating network at the transfer point or used for power generation. After the heat has been "transferred," the district heating network operator transports the heat to the customers. The now cooled water remaining in the closed system is returned to the circuit at a temperature of about 60°C. It then begins its journey through the loop again. 60°C is sufficient to maintain the thermosiphon effect, through which the entire mechanism runs independently.
gwf: At the same time, an Eavor loop is also supposed to generate electricity. How does that work?
Land: The heat exchanger feeds the heat through a separate circuit into an ORC (Organic Rankine Cycle) power plant. There, it heats isobutane, which in turn drives a steam turbine to produce 100% emission-free electricity. We rely on isobutane because it has a lower boiling point than water – so it turns into steam more quickly. The isobutane also remains in the cycle. After it has driven the turbine, it is cooled by an air cooler and later reheated using heat from the ground.
gwf: Can the ratio between heat and electricity production be adjusted?
Land: Of course. A common scenario would be a 50/50 utilization. However, depending on the location and demand, it may be more economical to focus on heat or electricity. Sometimes this also depends on the time of year: In winter, you may want to use a larger portion of the heat directly, while in summer, generating electricity may be more attractive.
gwf: How flexibly can a plant be controlled?
Land: Our goal is to operate at a constant base load – 8,760 hours per year. Depending on demand, we can then switch very flexibly between heat and power production. We can even accommodate certain demand peaks throughout the day by adjusting the water flow rate.
gwf: How does monitoring work during operation?
Land: During drilling operations, we continuously monitor volume and pressure in all systems to detect irregularities that could indicate leaks. In accordance with API standards and the regulations of the Bavarian State Mining Authority, we also regularly conduct training drills to ensure preparedness in the event of an emergency. Pipeline blockages are extremely unlikely because we ensure the stability of the wellbore both through comprehensive geomechanical analysis and our patented Rock-Pipe™ technology, which further stabilizes the lateral sections.
gwf: What happens if the rock shifts and damages the small channels of the Eavor Loop could this cause leaks?
Land: Before drilling begins, a comprehensive geomechanical analysis is conducted to ensure that lateral drilling is carried out in solid rock without significant seismic activity. Therefore, such incidents are not expected. This assumption is based on decades of operational experience from other deep drilling projects.
gwf: How do you earn your money – do you see yourself as a technology supplier or also as an operator?
Land: We pursue a diversified business model that adapts to the needs of our customers. The spectrum ranges from complete solutions to individual service modules. In concrete terms, this means: We can act as a plant manufacturer, as in Geretsried, but can also take over subsequent operation upon request. Another component is the licensing business. Companies that would like to implement Eavor-Loops™ themselves can acquire our technology licenses and thus gain access to our drilling methods and our know-how.
gwf: How long does it take to build an Eavor Loop?
Land: That's difficult to say, because the construction time depends on the depth and total length of the boreholes, as well as the number of loops, and, of course, the rock type. Average values are therefore not meaningful.
gwf: Suppose a municipal electricity or heat supplier were interested in an Eavor Loop. What requirements would its location have to meet?
Land: In principle, you can install an Eavor Loop almost anywhere. The reason is simple: If you drill deep enough, you will encounter warm rock layers anywhere on Earth. The only requirement for the rock is that there are no aquifers there. Because if they exist, hydrothermal geothermal energy is generally easier to implement. In Germany, however, this only affects 10-15% of the land surface. This is another reason why we see enormous potential for reservoir-independent deep geothermal energy here. We like to talk about "Forty by Forty": We consider 40 GW by 2040 to be quite realistic.
gwf: So, is it primarily a question of economic viability whether an Eavor Loop can be installed or not?
Land: Basically, yes. It is important that a sufficiently large plot of land and the appropriate energy infrastructure are available – although even this is not a deal-breaker, as Geretsried demonstrates, where the district heating network is still being built. Ultimately, the crucial question is whether the investments in drilling and new infrastructure will pay for themselves in the long term.
gwf: Is there a minimum size for projects?
Land: Our systems have a lower thermal limit of 15 MW – we have to deliver this output. We're open to the upper limit: The number of loops correlates with the heat demand. In Geretsried, we're building four loops of 16 MW each, for a total capacity of 64 MW. Having these on our doorstep provides the community with real locational advantages: Companies can secure their supply in the long term and are independent of energy imports. Incidentally, the systems are certainly expandable – if heat demand increases and the rock formation allows for the space.
gwf: Your Geretsried project is receiving considerable media attention. Why did you choose this particular location?
Land: The site has a drilling history – other companies had already drilled here before us, but they were looking for aquifers. This was a huge advantage for us: Our colleagues virtually confirmed that no aquifers existed, and provided us with valuable data about the subsurface. In addition, we were dealing with a community that was very open to geothermal energy.
gwf: What about the economic viability here?
Land: Geretsried is a "first of its kind" project – the first commercial Eavor-Loop™ worldwide. Therefore, economic viability is not the focus here. It is a technology demonstrator with which we are consciously investing in the learning curve. In other words, what we learn and optimize today will make future project implementations cheaper and more efficient. Our main focus is currently on reducing the costs of the drilling phase. To do this, we primarily need to become faster. And it's working: We already need significantly less time for the current drillings than for our first loops. This will significantly reduce the overall costs in the long term.
gwf: Will the project also be supported by scientific experts?
Land: Yes, absolutely. We are collaborating with several research institutions, including the Fraunhofer Institute, the Leibniz Society, the Technical University of Munich, the Technical University of Darmstadt, and the Karlsruhe Institute of Technology (KIT). We also employ our own geologists. Internationally, we cooperate with other institutes through our Canadian parent company. Eavor actively promotes scientific exchange.
gwf: Planning and approval procedures are often a major issue for energy infrastructure projects such as electrolyzers, sometimes even a showstopper. What about geothermal energy?
Land: Similar. We're hoping for the Geothermal Energy Acceleration Act. Unfortunately, it couldn't be passed in the last legislative period, but as far as we know, the current government is working on it. That would be very desirable: Project development must be simpler, and approval procedures must be faster – which usually means more digital. Digital processes would not only help us, but also the approving authorities.
gwf: How is the cooperation with the authorities in Geretsried going?
Land: I can't speak highly enough about this. The responsible mining authority works very professionally and is solution-oriented. The responsible officials are familiar with the facility and regularly monitor its correct operation. Despite this – or perhaps precisely because of it – they view us with great benevolent interest.
gwf: How is the population in Geretsried reacting to the project?
Land: Also with goodwill. We are in constant exchange with local elected officials and citizens. We have already held an open day. Our communication is open and transparent. We have also set up a visitor center with an exhibition to explain the technology to anyone interested. It's great fun and helps make our technology tangible.
gwf: What do you say to visitors who express ecological concerns?
Land: We can eliminate environmental impact risks for the Eavor technology. We harness geothermal energy in a sustainable way. The entire project is being monitored and inspected by the relevant authorities.
gwf: What is the timeline in Geretsried?
Land: We expect to be able to start producing electricity in 2025. This will be a crucial milestone – the final proof that our technology works. The municipality plans to build the district heating network in parallel with our project, so that the heat supply will begin somewhat later.
gwf: You're planning your next project in Hanover, Lower Saxony's state capital. How far along are you?
Land: We're currently preparing our site for drilling. Drilling is planned to begin in 2026, and heat supply is scheduled to begin in 2027. Hanover is another milestone for us – the first Eavor Loop™ in a major city. A total of two loops with a total capacity of 30 MW are being built, which will replace the existing coal-fired power plant. We're cooperating closely with enercity on this. Our collaboration also includes a long-term heat supply contract. I'd like to emphasize the dimensions of this project: Up to 250 million kWh of district heating per year! That corresponds to 15 to 20% of the city's annual district heating demand. This will supply up to 20,000 homes with climate-friendly heat.
gwf: Why did the Canadian company Eavor choose to implement its first major projects in Germany?
Land: In short, the "German Energy Transition" is a cross-party consensus. Such stable social frameworks are an aspect that should not be underestimated for large investments. Germany is therefore the ideal starting point for Eavor's global expansion of the technology: What we learn and demonstrate here opens the doors to markets all over the world. Germany will become the reference country for deep geothermal energy with closed-loop systems and we are proud to be part of this energy future.
gwf: Mr. Land, thank you for the interview!