also: じねつせい
noun
geothermal well
Technical term in geology and energy engineering for a well drilled to extract geothermal heat.
この地域では地熱井を掘削して発電に利用している。
In this region, geothermal wells are drilled and used for power generation.
温泉井 is a hot spring well, often shallower and used for bathing; 地熱井 is specifically for geothermal energy extraction.
Compound of 地熱 (geothermal heat) and 井 (well).