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,
What Is the What writes: "Over the course of many years, Dave and I have collaborated to tell my story... I told [him] what I knew and what I could remember, and from that material he created this work of art." The book is typical of Eggers' style: blending non-fictional and fictional elements into a non-fiction novel or memoir. By classifying the book a novel, Eggers says, he freed himself to re-create conversations, streamline complex relationships, add relevant detail and manipulate time and space in helpful ways—all while maintaining the essential truthfulness of the storytelling. However, not all critics were impressed. Lee Siegel sees