GDF-led group preferred bidder for Saudi plant-SEC

*GDF Suez consortium preferred bidder for power plant

*Saudi Electricity to sign plant deal within 2 months

KHOBAR, Saudi Arabia, March 3 (Reuters) - A consortium led by France's GDF Suez (GSZ.PA) is the preferred bidder to build a $2 billion power plant in Saudi Arabia, an executive at Saudi Electricity Co (SEC) 5110.SE said on Wednesday.

"The consortium (of GDF and al-Jomaih Group) offered the best complied bid of 0.1079 riyal per kilowatt-hour," Amer al-Swaha, head of independent power producer (IPP) projects at state-run SEC, told Reuters.

"We apologised to the other four bidders," he added.

The other bidding consortiums were Britain's International Power (IPR.L) with Saudi Oger and Korea Electric Power Corp (015760.KS); Mitsubishi Corp (8058.T), Acwa Power and Tokyo Electric Power (9501.T); Tenaga Nasional of Malaysia (TENA.KL), Sumitomo Corp (8053.T) and Saudi Binladin Group; and Japan's Marubeni (8002.T) with Kansai Electric (9503.T) and Masader.

"We are now in the project documentation phase to negotiate all agreements -- including the power purchase agreement -- and when we finish we will sign (the contract)," Swaha said.

"Financial close would take place by the end of May ... the signing is expected within two months."

"The cost of the plant is indeed within that range, around $2 billion," Swaha said. In October, Swaha said it would cost between $2 billion and $2.5 billion to build the 2,000 megawatt combined cycle IPP plant in the capital Riyadh.

SEC plans to add more than 12,000 megawatts to its generation capacity through 2015 to meet rising power demand in the top oil exporter. [ID:nLDE6220DS]. (Reporting by Reem Shamseddine; editing by Firouz Sedarat and Andrew Callus)