New Delhi, Nov 8 (IANS): State-run thermal power generator NTPC Tuesday said it planned to invite bids for procuring up to 20 million tonnes of coal from overseas firms to bridge supply short-falls.

Heavy rainfall in many of the coal mining areas coupled with a strike at major miner Coal India, led to a disruption in supply of the fuel to power plants across the country in October leading to unscheduled power cuts.

"We will seek bids for supply of imported coal for a period of 15-20 years. The amount will be up to 20 million tonne per year," NTPC chairman and managing director Arup Roy Choudhury told reporters here on the sidelines of a CII conference.

Choudhury said bids will be invited in next two to three months. Imported coal accounts for about 10 percent of the company's total annual requirement. It is the largest power generator with an installed capacity of over 35,000 MW.

However, the NTPC chairman said India could not rely on imported coal to meet rising demand as the cost of the fuel was much more than domestically available coal.

"The main issue is whether the power we generate is affordable or not," he noted.