地下热能是赋存于地球内部的一种巨大的能源。它和煤、石油、天然气及其它矿产一样,也是一种宝贵的矿产资源。目前,人们对于地下热能的利用,基本上是通过开采地下热水(汽)来实现的,因为地下热水(汽)是从地球内部将地下热能携带到地表的一种重要的媒介。即使是对岩浆或干热岩体的开发,也是要通过人工灌注冷水最终获得热水(汽)而加以利用的。所以说,地下热水(汽)是重要的地下热能资源。地下热能究竟有多大?有人曾对太平洋沿岸阿拉斯加的卡特迈火山区中的“万烟谷”地区,进行过地热能的估算。在这个24平方公里的范围内,分布了几万个天然蒸汽和热水的喷孔,平均每秒钟喷出(温度为97℃～645℃)的热水和蒸汽达23000多立方米,这里每年从地球内部携出的热量约为40万亿大卡,相当于600万吨煤燃烧时所放出的热量。由此可见,每年全球的火山和温泉从地球内部携带出的热 Underground heat is a huge source of energy that lives inside the Earth. Like coal, oil, gas and other minerals, it is also a valuable mineral resource. At present, the utilization of underground heat energy is basically achieved through the exploitation of underground hot water (steam), which is an important medium for carrying underground heat to the surface from inside the Earth. Even the development of magmatic or dry-hot rocks is exploited by artificially pouring cold water into hot water (steam). So, underground hot water (steam) is an important underground thermal energy resources. How big is underground heat? Geothermal energy estimates have been made for the “Cigarette Valley” in the Khatami region of Alaska on the Pacific shores. In this area of ​​24 square kilometers, there are tens of thousands of natural steam and hot water injection holes distributed, with an average of more than 23,000 cubic meters of hot water and steam being ejected per second (temperature: 97 ° C ~ 645 ° C) The annual heat output from the Earth’s interior is about 40 trillion kcal, equivalent to the amount of heat released when 6 million tons of coal are burned. This shows that every year, volcanoes and hot springs around the world carry heat from inside the Earth