Yangbajain Geothermal Field--Tibet
- Description: Tibet leads China in geothermal energy. More than 100 sites have good geothermal energy reserves, ranking first in China. Of the 169 geothermal fields and hot spring areas already surveyed, 22 percent
Tibet leads China in geothermal energy. More than 100 sites have good geothermal energy reserves, ranking first in China. Of the 169 geothermal fields and hot spring areas already surveyed, 22 percent show a water temperature of 80 degrees Centigrade, with the highest temperature at the hot spring mouth reaching 95.5 degrees Centigrade; most of them approach or exceed the local boiling point. About 26 percent have a water temperature of 60-80 degrees Centigrade; 35 percent, 40-60 degrees Centigrade; and 17 percent, lower than 40 degrees Centigrade. Tibet's geothermal heat discharge adds up to 550,000 kilocalories per second, equivalent to annual heat generation by 2.4 million tons of standard coal.
The most important field is Yangbajain Geothermal Field in Damxung, with eight double flash units for a total capacity of 24 MW, fueled from a water dominated shallow reservoir at 140-160°C with 18 wells of average depth 200 m. The place now is also a well-known scenic spot.
Yangbajain Geothermal Field is currently China's largest high-temperature steam geothermal field, and, moreover, one of the largest geothermal fields in operation in the world today. With a hot water temperature staying at 93-172 degrees Centigrade, the field has a natural heat flow of 110,000 kilocalories per second, equivalent in heat produced annually to about 470,000 tons of standard coal. It is expected to generate 150,000 kw of power a year.
The field extension is only 4 km2, although there are clear indications of a total thermal anomaly of 15 km2. The annual energy production is approximately 100 GWh, about 30% of the needs of the Tibetan capital, Lhasa. A deep reservoir has been discovered beneath the shallow Yangbajain field. It is characterized by high temperatures (250-330°C has been measured at 1,500-1,800 m depth). The field potential is estimated at about 50-90 MW. It is still un-exploited. A 2,500 m deep well has been drilled in 2004, reaching the deep reservoir at 1,000-1,300 m. Its evaluation is ongoing.