WAYANG WINDU GEOTHERMAL ENERGY

Located 40 km south of Bandung in West Java, Wayang Windu Power Generation is operated by Star Energy Geothermal (Wayang Windu) Limited a wholly owned subsidiary of Star Energy. It is managed under a Joint Operation Contract with Pertamina to develop geothermal resources within the 12,960 hectare contract area. An Energy Sales Agreement between Star Energy, Pertamina and PLN, a state owned utility company, gives Star Energy the right to develop up to 400 MW of electricity - generating capacity over a period of 42 years, with each generating unit being scheduled to operate for at least 30 years. The JOC has the potential to ultimately deliver more than the already-contracted 400 MW of base load electricity to power hungry West Java.

The first Unit (110 MW) at Wayang Windu was completed in 1999, and has been producing at full capacity (with an availability rate of over 98%) since 2000. At the time of its installation, Unit One was the largest geothermal turbine in the world.

In 2nd of March 2009, the Indonesian Minister of Energy and Resources officially opened Wayang Windu Unit 2, with generation capacity from a single turbine/generator, of 117 MW. So, Wayang Windu is now delivering a total of 227 MW of electricity to its buyer, PLN, which dispatches the electricity into the West Java transmissions grid. The potential for significant further expansion at Wayang Windu became apparent during the development drilling for Unit 2. Some of the wells drilled for Unit 2 tested more than 50 MWe of steam, and are producing sustainability at over 40 MWe, probably the largest sustainability steam production in the world for a single well.

Planning is now well advanced to expand Wayang Windu further, through the addition of a third Unit with generation capacity of 127 MW. Unit 3 should be on stream by mid-2014. In February 2010, Star Energy finalized a US$350 million bond issue, the proceeds from which will be used partly to fund the initial drilling and development work for Unit 3, with that worth due to commerce in the middle of 2010, using a drilling rig designed and built to Star Energy Geothermal specifications.

Truly, a world-class renewable energy facility, being operated to world class standards, Wayang Windu delivers real benefit to all Star Energy stakeholders.

Subsurface and Steam Above Ground System

Heat energy from the earth is extracted in the form of geothermal fluids. The fluids from several production wells are combined and delivered through two phase lines to the cyclonic separators where steam and residual water (brine) are separated. The steam is piped to the power station and the brine is returned to the reservoir through re-injection wells to help maintain pressure and prolong productivity of the reservoir. Steam from the separator is purified and dried in scrubbing lines and scrubber stations before entering the steam header in the power station

Power Station

Dry-saturated steam from the steam header drives the turbine which is coupled to a generator. The turbine converts the heat from the steam into mechanical energy and the generator converts mechanical energy into electricity. The steam passes through the turbine and is condensed in a direct contact condenser. The condensed water is then pumped to a cooling tower. The hot condensate is air cooled in the cooling tower and some of the cooled water is recycled to the condenser to condense the steam. Excess of condensate is returned to the reservoir through condensate injection wells. Any non-condensable gas in the condenser is taken out by  the Gas Removal System and dispersed to the atmosphere.
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