Geothermal Praxis in Germany Michael Würtele Michael Würtele Consulting Symposium for renewable energy Paris 4.05.2011
Geothermal Systems The choice of the right geothermal systems depends on heat demand cooling demand temperature which the customer needs. Geothermal application are devided in open and closed systems as well as in shallow and deep
The closed geothermal system 40 C heat exchanger pump peak load- and buffer boiler 70 C Advantages: only one borehole no risk to find an aquifer filled with clear water closed loop, therefore almost no maintenance, no abrasion, long living, reliable in operation environment friendly because there is no mass exchange 80 C dense rock 2500 m
The open geothermal system buffer boiler Advantages: degree of Effenciency 8 times in comparison to a closed system Normally no peak boiler Good system for power production 40 C heat exchanger 70 C pump 2500 maquifer 80 C
Geothermal applications at a glance
Main geothermal applications for shallow systems Rohre in Graben Pipes in a trench Verteiler im Haus Serienschaltung Grundwasserspiegel level groundwater pump Pumpe production well re-injection well horizontal loops 1-2 m depth Borehole heat exchanger 10-400 m depth Groundwater wells 4-50 m depth Heat pumps are required to use the heat at low, but constant temperatures
70 60 50 40 30 20 10 0 Geothermal Praxis in Germany Sold heatpumps in Germany in context to the oil price 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 140 120 100 80 60 40 20 0 number of units sold (x 1000) oil price (US-$/barrel) air source heat pump oil price (nominal, Brent/UK) GSHP
Governmental geothermal potential-maps Source: SMUL, GDNRW
Example for a restored living space in an old building in Freiberg I 885 m² Living space 12 Apartments 40 Residents 90 kwh/m² * a Heat quantity 1,36 Mio. Investing 7,10 /m² Rental price
Example for a restored living space in an old building in Freiberg II Estimation of the architect 75 kw = 50 W/m x 1.500 m => 15 bore holes with 100 m 89.000 + 10% Uncerntainty = 98.000 7,2% of the construction sum Estimation of the technician 48 kw without warm water 39 persons x 0,3 kw = 12 kw 60 kw => 6 bore holes with 140 m Annual heating demand: 65.000 kwh/a heating 15.000 kwh/a warm water
o o o o o o o o Geothermal Praxis in Germany Example for a shallow geothermal systems for a commerce project German Airtraffic Control in Langen Office building with 44 500 m² floor space Low-Energy-Office standard (LEO) 800 kw heating und 650 kw cooling 154 borehole heat exchangers à 90 m Reversible heat pump Conventional peak load coverage Base load 330 kw heating- and 340 kw cooling-power o 500 000 Investment extra costs for the geothermal plant o 125 000 /a savings on operating cost in relation to standard WSVO 95 o 80 000 /a savings on operating cost in relation to LEO without geothermal plant o Project without public subsidies o Rate of return 16%
recirculation flow line insulation flow line drive pipe cementation cementation Deep closed heat exchanger for heat production Construction: 3000 m drilling depth with 24 down to 9 5/8 (ca. 61 down to 25 cm ) steel support Annulus collector is filled from approx. 800 m with thermal conducting cement (approx. 2,3 W/mK GFK*-ascending pipe with 2 7/8 (ca. 8 cm) cementation Performance data: GFK-ascending pipe Flow rate 10 to 20 m³/h Thermal engine output 250 to 350 kw Heat amount 2,1 GWh/a with 8500 operating hours per year Temperature spread ca. 25 C *GFK = glass fiber reinforced plastic
Examples for deep closed heat exchanger Recreation spa in Arnsberg ~ 2730 m Communal heating net in Prenzlau ~ 2800 m, 450 kw University in Aachen ~ 2544 m
The deep closed heat exchanger in Arnsberg I Dimensioning of the depths terrestrial heat probe with DMT Softwaretool Technical data: Flow rate 10 to 20 m³/h thermal achievement 250 to 350 KW of amount of heat 2.1 GWh/a with 8 500 operation hours per year Borehole heat exchanger: 3 000 m drilling depth with 22 to 9 5/8 Steel casing annular space backfilling with thermal conductive cement GRP tubing with 2 7/8
Domestic technique: The deep closed heat exchanger in Arnsberg II Intelligent control engineering of the individual heating circles necessary integration of buffers cascade cross-linking with priority function Intention: Long heat requirement times with low thermal power long periods of operation of the geothermal plant (24h/d) short periods of operation of the peak load plant
Usage of mine water for the Design Centre at Zollverein coal mine Direct usage of mine water 600-1.200 m³/h Heat supply passive heat insulation Input 28 C / outlet 23 C after heat exchanger Today an open system In future a closed system
Using geothermal coldness in a hospital in Freiberg Using mine fan 3 km roadway From mine shaft to the air condition Pay back period ca. 9 years Start in 2003 (Source: Saxonian mining authority)
Deep open system for power production based on thermal water heat exchangers Construction: pump pump 3000 m drilling depth with 24 down to 9 5/8 steel support Performance data: production well re-injection well Drilling depth = 3500 m, temperature > 140 C Quelle: www.hotrock.de production well Robenkamp 36 MW-Consulting Mobil +49 15111984489Tel. +49 2327/972850 D 44869 Bochum Robenkamp mwc@geo-consens.de 36 Mobil +49 15111984489 Flow rate 65 l/s in each production well Power output approx. 5 MW Heat output 35 MW 8000 operating hours per year Temperature spread ca. > 60 C
Main geothermal areas in Germany 55 54 NORTH GERMAN BASIN 53 52 51 50 49 48 UPPER RHINE VALLEY MOLASSE BASIN 47 6 7 8 9 10 11 12 13 14 15 km 0 100 200 300
Geothermal power plants in Germany NEUSTADT-GLEWE (250 KW) LANDAU (2,5 3,5 MW) BRUCHSAL (500 KW) UNTERHACHING (3 MW)
A deep open system based on Enhanced Geothermal Systems (EGS) The concept behind EGS geothermal energy is relatively simple. To extract this geothermal energy, boreholes are created andwaterisinjectedintothehotgranite rock. The water is circulated through the rocks in an engineered, artificial reservoir or underground heat exchanger. This hot water returns to the earth s surface and it is pumped into a standard geothermal power plant. Inside the power plant, the hot water is converted into superheated steam, which drives a turbine and generator and produces electricity. There-fore, EGS geothermal energy relies on existing technologies and engineering processes such as drilling and hydraulic fracturing
Geothermal Praxis in Germany Thank you for your attention! MW-Consulting Robenkamp 36 D 44869 Bochum Tel. +49 2327/972850 Mobil +49 15111984489 mwc@geo-consens.de