Hot dry rock geothermal energy Hot dry rock geothermal energy Hot dry rock (HDR) is an abundant source of geothermal energy available for use. A vast store of thermal energy is contained within hot - but essentially dry - impervious crystalline basement rocks found almost everywhere deep beneath the earth’s surface. A concept for the extraction of useful amounts of geothermal energy from HDR originated at the Los Alamos National Laboratory in 1970, and Laboratory researchers were awarded a U.S. patent covering it. Although often confused with the relatively limited hydrothermal resource already commercialized to a large extent, HDR geothermal energy is very different. Whereas
More Hot Rocks (Big Hits & Fazed Cookies) it was recalled and something a little more practical was compiled (ABKCO would revisit this concept with 1975's "Metamorphosis"). The result was "More Hot Rocks (Big Hits & Fazed Cookies)". Featuring the hits that could not be shoehorned onto its predecessor, as well as first-time release of many previously UK-only releases, the double album was quickly pressed and distributed into North American shops in December 1972, reaching No. 9 in the US and going gold. Like "Hot Rocks 1964–1971", "More Hot Rocks (Big Hits & Fazed Cookies)" would not see an official UK release until 21 May 1990. Allmusic's Richie