Cost-efficient and space-saving drilling technology for geothermal energy applications

Short summary A Swiss start-up developed and patented a string-free drilling method. The technology enables fully automated deep drilling at a fraction of today's cost and reduces site size by 95%. This allows geothermal energy to be utilized in urban areas at competitive rates. The company is looking for a partner and manufacturer with whom the technology can be further developed and then jointly brought to market: Research & development cooperation agreement and/or investment agreement.

Full description Geothermal energy, drilling costs and space problems: Despite the energy crisis and global warming, about 60% of the heat demand in Europe is generated by burning fossil fuels. Although there are various renewable heat sources, none of them is ideal in application. The most promising would be the use of geothermal energy, because it is ubiquitous, 100% renewable and CO2 neutral. Unfortunately, the cost of drilling a geothermal well is prohibitively high, especially if you want to drill deeper than the average 300 meters. But if existing heating systems are to be converted to geothermal, deeper drilling is inevitable. Example: While a single 300m borehole can often meet the heating needs of a single-family home, fields of geothermal probes are required for large buildings (e.g. 300 geothermal probes are planned for a hospital in a big city in Switzerland). If the project has enough building area, a corresponding field can be realized relatively easily. It becomes problematic if a project does not have the necessary space. Imagine an existing multi-family house in an urban environment that has little surrounding area. In these cases, there is only one option: fewer but deeper geothermal probes. However, such projects are still not feasible, since there is no technology that can drill deep in a cost-effective and space-saving manner, yet. Cost-efficient and space-saving drilling technology: Specifically, the Swiss company has developed a machine that is located in the borehole and has all the necessary technologies to perform the drilling automatically. Unlike existing drilling methods (which are driven from the surface), our machine allows us to work in a very small space and largely automate the process. The drill is a 6 meter long, electrically (13kW/30A/380V) operated machine. This is lowered directly into the well on a steel cable. Once at the bottom of the well, the machine is locked by a gripper and then drills a predefined section with a percussive rotary mechanism (210kJ/1’500Nm). The drilled material from the section is collected within the machine and pulled back to the surface by the machine after the drilling process is completed (batch drilling). At the surface, the drill can be emptied and prepared for the next drilling operation. To minimize downtime, a second machine can be sunk into the borehole immediately. According to the simulation, the ascending and descending speed of the drill is about 15 km/h. The drilling advance is about 5cm per minute. Based on these and other variables, a borehole of about 1 km can be completed in 3-4 weeks. The handling on the surface can be automated and fits perfectly into a container (TEU - Twenty-foot Equivalent Unit container). This means that drilling can be carried out in an area of around two parking spaces. The automation allows to drill continuously and thus efficiently (analogous to a lawn mower robot). A major intrinsic advantage of the technology is that the borehole is always sealed against the outside. Since the container has different pressure valves and sensors, a blowout can be easily detected and prevented. Partner sought: The start-up is now looking for a cooperation partner with whom the technology can be industrialized, manufactured and jointly brought to market. Specifically, they are looking for a partner who can finance the development, produce and distribute the machine in an exclusive relationship. The partner should be one of the leading market players in Europe for geothermal energy applications who would like to unlock a huge market potential by penetrating previously non-accessible sites due to area restrictions. The innovation comes from the combination of existing technologies. Most of the components are already existing in one form or another but had to be adapted to our specific application. In comparison, one could imagine the technology more like a tunnel boring machine for vertical use.

Advantages and innovations

• The automated batch drilling process has the advantage that the cost per meter drilled increases almost linearly, so that on average the cost per meter is expected to be $70. Consequently, the total cost of deep drilling can be reduced by 99%.
• Thanks to the high degree of automation, costs and personnel required can be kept low.
• The entire drilling machine is located in the borehole and thus requires less drive power and space at the surface. Specifically, a deep borehole (up to 3000m) can be drilled with a construction area of around 25 square meters. Ideal for the urban environment.
• A major intrinsic advantage of the technology is that the borehole is always sealed against the outside. Since the container has different pressure valves and sensors, a blowout can be easily detected and prevented.
• Also, the overburden does not have to be flushed to the surface, as it is collected in the drilling rig and transported to the surface (batch process).
• The collected drill cuttings can be easily analyzed at the surface so that a database of geological conditions can be established.
• The machine is equipped with different sensors, so that during the ascent and descent of the machine the borehole can always be measured, and changes can be detected.
• Enables closed loop geothermal (circular economy)
• The patent application covers the entire hardware as well as the drilling process

Contact / source: NEXT EEN Widgets (europa.eu)