Wang Noi CCGT, Thailand

The combined-cycle Wang Noi power station is now generating 2,027MW for Thailand's central region. The plant is in Ayuthaya, 70km north of Bangkok, and was Electricity Generating Authority of Thailand's (EGAT) largest combined-cycle investment, costing $1.5 billion.

When first approved in July 1994, the project was planned as four combined-cycle power trains of 300MW each. However, for reasons of economy and feasible transportation of heavy equipment to the project site, the project was instead modified to three combined-cycle power trains of 600MW each. In each block are two 200MW heavy-duty combustion turbine units with two heat recovery steam generators and a 200MW steam turbine generating unit.

Electricity Generating Authority of Thailand (EGAT) began construction work on the Wang Noi CCGT power station in 1995 to meet the country's surging demand for power. It was one of five large power generation projects EGAT began to meet domestic power demand growth which at that time was about 12%, or 1,200MW per year.

In the 1990s, the IMF called for the complete restructuring of Thailand's electricity industry. EGAT has set up a private company, Electricity Generating plc (Egco), to operate two gas-fired power stations. EGAT will continue to own and operate Thailand's national power transmission system and will buy electricity from privatised and new private producers to supply to distributors and large customers. Gas-fired stations account for about a half of Thailand's installed generating capacity, and oil-fired power plants account for 20%. The kingdom's remaining power capacity is provided by various hydroelectric and lignite-fired schemes.

With current paid-up capital of 5,265 million baht, EGCO is structured as a public holding company to invest in subsidiary companies with core business in generating electricity and in other related energy business companies. EGAT currently remains EGCO's major shareholder with approximately 25% stakes. In 2002 EGAT received a dividend of 167 million baht from EGCO.

WANG NOI PROJECT DESCRIPTION

The first two power trains were ordered in 1994, unit one and two gas turbines were all on line by the end of 1996. Unit one steam turbine went on-line in September 1997, followed in November 1997 by unit two steam turbine. The official synchronisation of unit three gas turbines was completed by the end of 1997 and the third unit steam turbine was completed in April 1998. Total plant cost was just under $1.5 billion.

The plant consumes around 280 million ft³ per day of natural gas, supplied from a gas separation plant at Rayong, owned by the Petroleum Authority of Thailand (PTT).

In September 1999, Wang Noi power plant became the first power plant in Thailand to receive ISO 14001 certification, providing assurance that its environmental management system is up to international standards.

CCGT PLANT MAKE-UP

Mitsubishi Heavy Industries won the turnkey equipment supply contract for Wang Noi. It had previously completed EGAT's second largest CCGT installation, the 1,375MW Bang Pakong plant. US group Black & Veatch provided engineering services and Jurong Engineering, Singapore, won a mechanical and electrical works contract for the plant. Civil works were contracted to local Thai groups. Danish company KE Burgmann supplied expansion joints, insulation and other components to Mitsubishi Heavy Industries for the turbines.

A consortium led by Nichimen Corp, which also includes GEA Thermal - Dynamic Towers Inc and Toyo-Thai Corp, was awarded a $3.8 million contract to supply and install cooling towers for the first phase of the Wang Noi power station. GEC Alsthom supplied and supervised the installation of seven 200t 250MVA 525/242-22kV transformers. This was part of a $23 million contract to supply 17 transformers to three EGAT power stations.

FUEL SUPPLY

PTT awarded an Italian-Japanese consortium of Saipem and Mitsui & Co a $145 million contract to build a 154km-long pipeline from Ratchaburi power plant to Wang Noi. The 30in-diameter, high-pressure pipeline was completed in 2000 and allows PTT to supply Yadana gas to Wang Noi power station and other customers through its grid network.