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,
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