| geothermal energy An energy produced by tapping the earth's internal heat. At present, the only available technologies to do this are those that extract heat from hydrothermal convection systems, where water or steam transfer the heat from the deeper part of the earth to the areas where the energy can be tapped. The amount of pollutants found in geothermal vary from area to area but may contain arsenic, boron, selenium, lead, cadmium, and fluorides. They also may contain hydrogen sulphide, mercury, ammonia, radon, carbon dioxide, and methane | 地热能 (通过开发地球内部热量而产生的能量。目前唯一能够这样做的技术是从水热对流系统中提取出热量。水热对流系统是通过水或蒸汽将热量从地球深处向能量能被提取的地方转移。地热中含有的污染物的多少根据区域的不同而不同，包括砷、硼、硒、铅、镉氟化物，也包括硫化氢、汞、氨、氡、二氧化碳和甲烷等。) |
