North Bangkok Combined Cycle Power Plant, Thailand
The North Bangkok Combined Cycle Gas-Fired Power Plant (CCGP) is located in Bang Kurai district in the Nonthaburi province of Thailand. The gas-fired power plant is owned and operated by the state-owned utility Electricity Generating Authority of Thailand (EGAT).
The North Bangkok CCGP has two power generating blocks. The 700MW Block 1 was commissioned in late 2010, while an engineering, procurement and construction (EPC) contract for the 850MW Block 2 was awarded in February 2013. A consortium of Alstom and Sumitomo Corporation of Japan delivered the second block.
Starting commercial operations in June 2016, Block 2 makes the North Bangkok CCGP one of the largest power plants in Thailand. It also contributes to the national target of 55,000MW generating capacity by 2030, while minimising CO2 emissions.
Details of North Bangkok CCGP Block 1
The EPC contract for the 700MW North Bangkok CCGP Block 1 was awarded to a consortium of Sumitomo Corporation, Hitachi and Italian-Thai Development (ITD) in March 2007. The plant was handed over to EGAT for commercial operation in 2010.
The plant comprises two gas turbines and one steam turbine. It uses natural gas supplied through the pipelines of Petroleum Authority of Thailand (PTT pipelines) as its primary fuel. The secondary fuel used by the plant is light oil or diesel. The power generated by the plant is fed into the national grid.
GE supplied its 9001FA gas turbines and the steam turbine for the plant. The generators were provided by Hitachi, while the heat recovery steam generators (HRSGs) were supplied by Cockerill Maintenance & Ingénierie (CMI). Italthai provided the Balance of Plant (BoP).
The North Bangkok CCGP Block 1 was built at an estimated cost of THB17.3bn ($590m) at 2010 prices.
The Environmental Impact Assessment (EIA) approved for the Block 1 project also covered future capacity to the plant.
Plant details and contractors for North Bangkok CCGP Block 2
The combined-cycle Wang Noi power station is now generating 2,027MW for Thailand's central region.
An international tender for the North Bangkok CCGP Block 2 EPC contract opened in February 2012. The contract was awarded one year later to the Alstom-Sumitomo consortium with an estimated cost implication of THB14.6bn ($500m).
With its €225m ($292m) share in the contract, Alstom supplied the gas and steam turbines, turbo-generators, HRSGs and the distribution control system (DCS) for the plant.
It also provides service and maintenance to the plant over 12 years under a separate contract.
Sumitomo carried out the overall civil and installation works of the project. It also provided major facilities for the plant, including the water treatment facility and the substation system.
Plant layout of the North Bangkok CCGP Block 2
Block 2 was built adjacent to the existing plant. The new plant comprises two generating units, with each unit consisting of one combustion turbine, one heat recovery steam generator, one steam turbine, and one generator.
The combined-cycle operation of the plant utilises sequential combustion technology with natural gas as the primary fuel. Electricity generated is transmitted through a 230kV underground line to the north Bangkok substation located 500m away from the plant.
CCGP power plant technology
The North Bangkok CCGP Block 2 is installed with Alstom's upgraded GT26 gas turbines. The GT26 was introduced in the mid-1990s as a 50Hz sequential combustion gas turbine. Its upgraded version offering greater efficiency and operational flexibility was launched in 2011.
North Bangkok CCGP Block 2 is the first commercial operation in the world to use the upgraded GT26 turbines.
The upgraded GT26 features achievable efficiency of more than 60% in combined cycle operation. It also offers greater performance as it is capable of generating 350MW in less than 15 minutes. Its most distinguishing aspect, however, is the MXL2 feature incorporated for greater operational flexibility, which gives the operator the option to switch between two modes of operation (namely M and XL) on-line as needed.
The turbine can be operated in M mode if there is a demand for high performance, or it can be switched to the XL mode, which offers less performance but optimises the lifetime of the turbine.
The combined-cycle operation at Block 2 of the North Bangkok plant uses 22-stage subsonic compressor to feed air to the combustor.
The sequential combustion mechanism of the plant is designed to generate cleaner power with low NOx emissions.