| Abstract |
So far, there is no electricity generation from geothermal sources in Switzerland. However, there is a major project underway (DHM: Deep Heat Mining) with the aim to establish, within the next 10 years, HDR-type co-generation plants at sites in Basle and Geneva. The DHM project is funded by federal and local governments; some private funding is also provided. Geothermal energy utilization for direct use is advancing well in Switzerland. Geothermal heat pump systems (GHP) spread out rapidly, with annual increase rates of up to 15 %. The reasons for this rapid market penetration are technical, economic, and environmental. In 2004, the total installed capacity of GHP systems was 525 MWt with an energy production of about 780 GWh. With over 1 GHP units every 2 km2, their density area-wise is the highest worldwide. Thus, Switzerland holds a prominent rank worldwide in geothermal direct use. In addition, novel applications, like the use of warm tunnel waters and of other innovative solutions (e.g. "geo- structures" and road and runway de-icing) are emerging. The total installed capacity for direct use was 585 MWt in 2004, with the following breakdown: " GHP with borehole heat exchangers (BHE; the overwhelming majority) and horizontal loops 77.0 %, " GHPs with groundwater 12.9 %, " spas 7.0 %, " deep aquifers for space heating 1.0 %, " tunnel waters and deep BHEs 0.9 %, " geo-structures (generally foundation piles for combined heating and cooling purposes) 1.2 %. In total, 1'190 GWh of energy were produced in 2004. Over thousand boreholes are drilled every year to install double U-tube BHEs into the ground. Average BHE drilling depth is now around 150-200 m, however, depths of more than 300 m are becoming increasingly common. Average BHE cost (drilling, U-tube installation incl. backfill) amounts now to around 40 Ä per meter. In 2003, a total of 550 km (!) of BHE boreholes have been drilled. The total energy of 1'190 GWh produced from geothermal sources in Switzerland in 2004 represents a considerable substitution of fossil fuels (~100'000 toe). Equally significant is the reduction of CO2 emission, which amounts to about 300'000 tons of CO2 per year. |