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
Note from the Underground (Buffy comic) return Sunnydale to its natural state. Buffy rescues Xander and Dawn from The Scourge. Buffy must fight for her friends' and family's lives, and also for the right to live her own life, Faith and Angel help. "Buffy" comics such as this one are not usually considered by fans as canonical. However, unlike fan fiction, overviews summarizing their story, written early in the writing process, were approved by both Fox and Joss Whedon (or his office), and the books were therefore later published as officially Buffy merchandise. Note from the Underground (Buffy comic) "Note from the Underground" is a story