KHOBAR - Three international firms have made bids ranging between $3.94-$4.34 billion to build a 2,400 megawatt power (MW) power plant for Saudi Electricity Co, an industry source said on Thursday. South Korea's Doosan Heavy Industries & Construction is the lowest bidder with SR14.8 billion ($3.94 billion), said the source, who requested anonymity. Hyundai Heavy Industries' bid came at SR14.9 billion and that of France's Alstom amounted to SR16.3 billion, he said. Doosan declined to comment, Hyundai Heavy Industries and Alstom were not immediately available for comment. Bidding for the plant closed on Dec. 15. The power plant 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. SEC's capacity is around 40,000 MW. The bids were in line with SEC's cost estimates. An SEC executive estimated the cost of the plant at around $4 billion, down from an initial estimate of around $5 billion. The executive said at the time contracts would be awarded by the year-end but contractors had said it may take until the first quarter for the awards to be made. The plant is expected to be completed in the summer of 2014. The project provides for the addition of four units, each with a capacity of 600-700 MW. Saudi Arabia is facing rapidly growing power demand as the kingdom builds infrastructure and industries that would help its plans to diversify its economy away from heavy reliance on oil exports revenue. Demand is growing at around 7-8 percent per year.