Seite - 140 - in Water, Energy, and Environment - A Primer

industry to educate people about GHPs and facilitate their deployment. This led to establishment of the Geothermal Heat Pump Consortium, now known as GeoExchange. One important response on the part of some utilities was to advance themoney to homeowners for drilling the heat exchange holes, a major barrier to heat pump deployment. The utilities clearly recognized the benefits frompeakpower reductions.Consumers repaid the loans from the savings on reduced energybills. Today, GHPs are widely used around the world, with more than 700,000 installed in theUS, where new installations are occurring at about 50,000 per year. The US Department of Defense is a major user of GHPs, and pioneered in their use in the late 1990s by installing over 4000GHPs in housing at amilitary base inLouisiana.A side effect of theUSprogram was the introduction of GHPs to China in 1998, when I first went to China on a government-to-government visit. Today China is incorporating GHPs into many if not most of its newbuildings. 8.6.4 Anunusualsourceofgeothermalenergy Anunusualway to use geothermal heat is tapping the hot fluids being expelled from hydrothermal vents (also called ‘Black Smokers’) at spreading ridgeson theocean floor. They are the result of cold seawater leaking through fissures in the ocean crust into hotmagmabelow the crust, being heated and reemerging as hot water vents enriched with dissolved minerals (sulfur, copper, zinc, gold, iron). These minerals deposit out on the ocean floor when the heated water (some of these vents reach temperatures of over 700°F) hits the cold seawater, creatingmassive depositswhich obviouslywill attract commercial attention. The energy content of this hot water is also immense and represents one way of tapping the heat energy in magma. Needless to say, tapping this heat energy requires operating at great depths in oceans under extreme Water,Energy, andEnvironment–APrimer140