The Add-On project for Grati CCPP Block 2 was initiated in response to the increasing electricity demand within the Java-Madura-Bali (Jamali) system, which experienced an average growth of 4.84% during the 2021–2023 period. This Add-On development involves the installation of a Heat Recovery Steam Generator (HRSG) and a Doosan Skoda Steam Turbine (ST) DST-S10-5CA1, which utilize exhaust gases from three Mitsubishi MW-701D Gas Turbine (GT) units. This modification increases the installed capacity of Block 2 from 302.25 MW to 497.25 MW. The HRSG technology also reduces greenhouse gas (GHG) emissions since power generation from the ST produces no direct GHG emissions.
The Add-On at Grati CCPP Block 2 operates using natural gas and modern technology, with the fuel currently supplied from gas wells located in East Java, managed by Medco Energi Sampang Pty. Ltd., Kangean Energy Indonesia Ltd., and PT Inti Alasindo Energy. Initially, Block 2 operated in single cycle mode since 2002, with exhaust gases from the GTs released directly into the air at a temperature of 500°C. These high-temperature exhaust gases can now be recovered as an energy source to heat water in the HRSGs, producing steam to drive the ST and generate electricity. This technological upgrade transforms the system from single cycle to combined cycle.
In this mitigation effort, exhaust gases from the three GT units (GT 2.1, GT 2.2, GT 2.3) are used to power HRSG units 2.1, 2.2, and 2.3. The steam produced by these HRSG units is then channeled into a single ST unit (ST 2.0), increasing the installed capacity by 195 MW. The entire net electricity production from the Grati CCPP Block 2 Add-On supplies power to the 150 kV system, which is connected to the 500 kV Jamali grid. As of 2023, the Add-On had delivered a total of 5,275.97 GWh of electricity.
According to the Feasibility Study of Add-On Grati Power Plant, the economic lifespan of this Add-On project is 20 years. The conversion to a combined cycle significantly increases electricity production using the same amount of fuel, boosting system efficiency from 24.06% to 38.70%. While technically, combined cycle efficiency can reach up to 42.26%, actual performance is lower due to load regulation by the Central Load Control Unit (UIP2B). The realized gas supply to the Grati CCPP Block 2 Add-On is 42 BBTU.
Registry Number
VER-11-PR-XII-2024-22454
Activity Period
January 2021 – December 2027 (84 months)
Implementation Status
Ongoing
Project Owner
PT PLN Indonesia Power (Private Sector)
Address: Jalan Gatot Subroto Kav. 18, South Jakarta, DKI Jakarta Province – 12950
Price: Start from $12.07/tCO2e
