Lightning Shatter Rock: New Drilling Method for Deep Geothermal Energy

Drilling costs for deep geothermal energy could reduce significantly following development of new drilling technologies that use the electric impulse method (lightning) to break the rocks. This is according to a recent article reported successful destruction of rock in hole using this method in Germany early in September. The trials conducted on the TU Bergakademie Freiberg campus involved a 12m high drill tower, constructed by the researchers themselves, new "super drill" that destroys the rock with lightning - more effectively and faster than conventional drilling methods.

The new drilling method is designed to reduce the cost of deep geothermal drilling in the hard rock, for example in the granite, which is typical in Saxony, to the extent that the use of geothermal heat for the environmentally friendly production of heat and electricity becomes economical.

Geothermal power plants are basic and environmentally friendly. However, the extremely high costs for the necessary deep drilling have hitherto prevented a broad breakthrough on the energy market. The fact that the electric impulse method can be used for drilling has so far only been demonstrated in the laboratory scale. Now scientists have succeeded in successfully testing the process in a real well.

"The joint project of the TU Bergakademie Freiberg and the TU Dresden not only makes an important contribution to the energy demand, but also shows that the process developed in the laboratory is practical," says Matthias Reich, professor of drilling technology, special gravity equipment and mining machinery at the TU Bergakademie Freimberg.

In the electro-pulse process (short EIV) about 25 flashes with a voltage of 500,000 volts are sent through the rock per second. This corresponds approximately to the voltage with which the large power plants feed their electricity into the networks. The lightning flashes blast the drill hole from the borehole hole. The method operates in contrast to conventional drill bits without contact and without moving parts. The constant expensive removal and re-installation of the several-kilometer-long drill rigs for replacing dull chisels is no longer required by the EIV, which considerably reduces drilling costs.

Scientists from the TU Bergakademie Freiberg and TU Dresden as well as industry partners are involved in the project funded by the BMWi. Work on the test bore should continue until mid-October.

Source: Euwid