Energy in South Australia and trap in the deeper heat. Due to the low permeability of granite, the hot rocks must undergo hydraulic fracturing and be stimulated to allow a flow of water through the system to produce energy. This heat is slowly conducted to shallower rocks near the surface. Petratherm propose developing the geothermal energy in the more permeable sedimentary rocks that overlay the hot granite, a process called Heat Exchange Within Insulator (HEWI). While somewhat cooler, in many cases they do not require hydraulic fracturing. It is estimated that one percent of geothermal energy shallower than five kilometres below the earth's surface
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