World Premiere as Super-Drill Blitzes Freiberg – Massive Potential for Deep Geothermal Energy
The TU Bergakademie Freiberg campus was the scene of a world first recently (September 5), when the so-called “electro-impulse technique” was successfully used to pulverize rock in an actual borehole – with bolts of electricity.
“With this success, the joint project between TU Bergakademie Freiberg and TU Dresden has made an important contribution to Germany’s energy transition, while demonstrating that the laboratory-developed technique is practicable in the field,” says Matthias Reich, Professor of Drilling Technology, Special Underground Construction Equipment, and Mining Machines at TU Bergakademie Freiberg.
That the electro-impulse technique can be used for drilling has previously only been demonstrated on the laboratory scale. Now scientists have succeeded in testing this process in a real borehole – and with positive results.
The electro-impulse technique has the potential to reduce drilling costs dramatically. With this new technique, the cost of drilling deep boreholes for geothermal energy in hard rock (e.g. granite, which is typical in Saxony) should be reduced to such an extent that the use of geothermal energy will become cost-effective for the environmentally friendly production of heat and power. Power plants that use geothermal energy are environmentally friendly and provide base-load electricity. The extremely high costs involved in producing the deep boreholes required, however, have prevented geothermal energy from making a breakthrough in the energy market.
Grant-aided by the German Federal Ministry for Economic Affairs and Energy, the current project is a boon for Germany’s transition to renewable energy sources. The project is the work of the Institute of Drilling Engineering and Fluid Mining at TU Bergakademie Freiberg, the Chair of Construction Machinery at the Institute of Fluid Power at TU Dresden, the Institute of High Voltage Engineering at TU Dresden, and a range of industrial partners (BAUER Maschinen GmbH, GeoThermal Engineering GmbH, BITSz Electronics GmbH, Baker Hughes, Werner Industrielle Elektronik und ILEAG e.V.). Work on the test borehole will continue until mid-October, and the preliminary results are the pinnacle of some ten years of research work.
With the electro-impulse technique, approx. 25 bolts of electricity (with some 500,000 volts) are projected into the rock per second. This corresponds roughly to the voltage with which large power plants feed their power into the grid. The bolts of electricity effectively blast drilling debris from the bottom of the borehole. In contrast to conventional drilling bits, this technique operates without either contact or moving parts, reducing wear costs considerably. Drill pipes can be up to several kilometers in length, and normally have to be removed to change blunt drill bits before being reinserted. With the electro-impulse technique, this process is eliminated, with the time saving alone reducing drilling costs significantly.
This time-lapse video from YouTube shows the construction of the drilling rig by the researchers (from 21 August to 5 September, 2017). The film ends with the beige-colored drilling pipe being fed into the borehole. This is the new “Super Drill”, which pulverizes rock with bolts of electricity – both more effectively and faster than conventional drilling techniques.
Further information on both process and project:
- http://tu-freiberg.de/sites/default/files/media/institut-fuer-bohrtechnik-und-fluidbergbau-230/handout_eiv.pdf (poster)
- http://www.bine.info/fileadmin/content/Presse/Projektinfos_2015/PM_13_2015/PM_1315_internetx.pdf (article by the Federal Ministry for Economic Affairs and Energy – BMWi)
Prof. Matthias Reich, Tel. +49(0)3731 39-2491 bzw. -2494, Matthias [dot] Reichtbt [dot] tu-freiberg [dot] de