But it is underused worldwide. Some 18 countries use the energy, but the power generated is only a small fraction of national production. The real hindrance to developing geothermal has been that key data, for sustainable and environmentally safe management, have been virtually impossible to ascertain. Isotope hydrology techniques can help answer such questions very precisely and quickly. Radioisotopes used as tracers can be tracked deep underground.
Stable isotopes can reveal directions, pathways and rates of waterflow in and out of reservoirs.
These powerful tools can also show where to drill, and how best to feed extracted water back into the reservoir thus ensuring sustainable use of the resource and that the environment is not harmed by the waste water. Recent IAEA technical co-operation projects have helped Ethiopia, Greece, China, Guatemala, Indonesia, Mexico and Nicaragua to develop capability to exploit geothermal resources by transferring knowhow and equipment for applying isotopic techniques. El Salvador and the Philippines are already harnessing geothermal heat. The IAEA is supporting activities because of the substantial commitment and high priority given to geothermal energy in the national economic development programmes. The Philippines is already the worl's second largest geothermal electricity producer.