The researchers estimate that some 13 trillion trillion (1024) joules lurk deep underneath U.S. soil and that 1.5 percent of that energy is recoverable, without taking cost into account.

• 根据研究人员估计，美国地下深处蕴藏的热量约有13兆兆（1024）焦耳，不考虑成本的话，其中有1.；5%25的能量可以开采出来。