The fastest growing segment of the geothermal industry is geothermal-heat pumps. In 2008, about 250 US drilling rigs will complete over 25,000,000 feet of vertical bores at a market value near $300 million. Current US investment in geothermal heating and cooling systems exceeds $800 million, annually, and Canada installs about 10% more.rnIn the US alone, 1.8 million vertical loops of water-filled, high-density polyethylene (HDPE) pipe annually exchange 2,500 (net) megawatts of thermal heat with the earth at an estimated 100% capacity factor. Total-global capacity is about 50% higher. This form of geothermal drilling, looping, and grouting procedures has evolved to a state of high efficiency,low risk, and affordable cost: 8,000 installed MWth of geothermal-heat pumps operate in the US near a 30% load factor.
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