Abstract: Deep drillholes of 2 or more meters diameter down to 14-20 km and more, are with current technology extremely expensive and often not possible. Such wells are needed to run almost anywhere old nuclear/coal powerstations cheaply by geothermal steam: Water/cool steam down and hot steam up. As by-product energy is CO2-free. Steel and rock can be cut by heat of any type: conductive, radiative and heat-transmission by contact. This principle is used in the steel industry by (translated from German) “burning-cutting machines”. In addition rock can be cut by heat-induced evaporation. A ring with radii and segments that carry one to hundreds heat-generating elements moves through the rock. This way, with fairly low energy-consumption, coring is done at a high speed at almost (any) diameter. Stafette-type core- and equipment transport ensures the speed of the drilling system.