State-run utility Saudi Electricity Company (SEC) plans to bring online more than 4,750 megawatts of natural gas-fired generating capacity in Riyadh between 2015 and 2017, the company said on Sunday.

One power plant there, known as PP10, will have an additional 1,150 MW unit operational from May 2015, SEC said. Two other plants, PP13 and PP14, with a combined capacity of 3,600 MW, would come online in August 2017.

Meanwhile, some units of plant PP12, which will have a capacity of 1,740 MW, have started operations, the company added. Riyadh accounts for about a quarter of SEC's customers.

The company's total available generating capacity nationally was 61,625 MW at the end of June this year.

SEC will spend 622 billion riyals ($166 billion) between now and 2023 on adding 40,000 MW of installed generating capacity and expanding transmission and distribution networks, chief executive Ziyad Alshiha was quoted as saying in March by state news agency SPA. – Reuters