South Korea's Doosan Heavy Industries & Construction has cut by SR2.1 billion ($559.9 million) a proposal it made for the construction of a 2,400 megawatt power plant in Saudi Arabia, an industry source said.

The plant, in Rabigh on the western coast of Saudi Arabia, would have capacity of 2,400 to 2,800 MW, some 12-14 percent of the 20,000 MW the SEC plans to add through 2018, at an estimated total cost of $80 billion.

Doosan remains the lowest bidder to build the plant for state-controlled Saudi Electricity Company (SEC). Doosan revised its bid to 12.7 billion riyals from 14.8 billion riyals.

The other two bidders, Hyundai Heavy Industries (HHI) and France's Alstom have also revised their bids to 13.9 billion riyals and 14.4 billion riyals respectively, the source said.

A Doosan official, who declined to be named, confirmed his company was the lowest bidder for the project. He added a decision on the project was likely to be taken late in August or early September.

Hyundai Heavy confirmed it made a revised offer but declined to confirm prices.

A spokesman for Alstom said no decision had been made yet and that the company expected a decision to be taken in the coming weeks. He declined to comment on the level of Alstom's offer.

Bidding for the plant closed on December 15. The bids were below SEC's cost estimates.

An SEC executive had estimated the cost of the plant at around $4 billion, down from an initial estimate of around $5 billion.

Saudi Electricity secured in April a 15 billion riyal ($4 billion) soft loan from the government. The bulk of the loan will finance the construction of the plant in Rabigh where the giant King Abdullah Economic City is under construction. The plant is expected to be completed in the summer of 2014.-Reuters