World Geothermal Congress 2020+1
March - October, 2021

8 Years Operation Experiences Ulumbu 4 x 2.5 MW Power Plants

Sugeng TRIYONO

[PT. Indonesia Power, Indonesia]

The Ulumbu geothermal field is located on the Flores Island, East Nusa Tenggara Province – Indonesia. The natural thermal activity at Ulumbu area is estimated 100 MW, through fumaroles and numbers of warm bicarbonate type springs with low chloride contents. Power plants with total capacity of 10 MW consists of 4x2.5 MW to utilize one of three deep exploration wells were drilled in 1994 – 1995. Those 4 units are 5 MW back pressure turbine and 5 MW condensing turbine. The first unit back pressure was generated in November 2011, and the last unit was accomplished in September 2014. Power house is located on the valley of the flank area, on the same area of exploration drilling pad. Non condensable gas in contact with plume from cooling tower is not able to disperse freely, but most of gas falling down in area of power plants. The geo acidity fluid is resulting heavy corrosion on balance of plants as well, contribute to the force outage due to mall function of instrument control facilities caused by corrosive environment. Dry steam from shallow reservoir, have experienced of heavy scale deposition on the first stage blades of back pressure turbine. Within 6 (six) months, the back pressure turbines shown decrease capacity more than 10%. To secure sustainability of power plants, it is needed to drill more wells to supply the existing exploration wells, as well, the new extension power plants shall be located on the high elevation level to assure the NCG disperse on out of power plant area.

        Topic: Power Generation Paper Number: 26026

         Session 29D: Power Generation 2 -- Equipment [Tuesday 15th June 2021, 02:00 am] (UTC-8)
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