Hot dry rock geothermal energy makes use of hot fluids found naturally in basement rock; but such HWR conditions are rare. By far the bulk of the world’s geothermal resource base (over 98%) is in the form of basement rock that is hot but dry—with no naturally available water. This means that HDR technology is applicable almost everywhere on earth (hence the claim that HDR geothermal energy is ubiquitous). Typically, the temperature in those vast regions of the accessible crystalline basement rock increases with depth. This geothermal gradient, which is the principal HDR resource variable, ranges from less than 20 °C/km to over 60 °C/km,
Duke Energy Center for the Performing Arts Duke Energy Center for the Performing Arts Duke Energy Center for the Performing Arts is the main venue for the performing arts in Raleigh, North Carolina. The naming rights to the center currently are held by Duke Energy (formerly Progress Energy), which purchased them from the city in 2005 for a 20-year term at the cost of $7.5 million. The original naming rights previously were held by Business Telecom, Inc. (now EarthLink)), and the facility was known as the BTI Center for the Performing Arts from 1997-2005. BTI Owner Peter Loftin donated $3.1 million to the center in 1999, matching