The US company Unocal Corp. has completed drilling of a geothermal well in the Silangkitang region of north Sumatra with an estimated capacity of 50 MW.

The development well, Silangkitang 1-3, is the fifth drilled in the region. It will supply hot water to the Sarulla Unit 1 generating plant.

The well is 2160 m deep. It has a registered a flow rate of 860 000 l/h under restricted flow conditions, equivalent to 37 MW of capacity. Under unrestricted flow conditions, this could exceed 50 MW. According to Unocal, this would make it one of the largest capacity wells in the world.

The confirmed cumulative capacity of the Silangkitang field is now around 90 MW.

Unocal North Sumatra Geo-thermal, a joint venture between Unocal and Indonesian oil company Pertamina, has a contract to supply 1000 MW of electricity from the Sarulla contract area in north Sumatra.