Smoke billows out from the cooling towers of a coal-fired power plant in Ahmedabad, India Thomson Reuters NEW DELHI (Reuters) - India has identified 5.5 gigawatts (GW) of inefficient coal-fired power plants to be retired, Power Minister Piyush Goyal told lawmakers on Thursday, as the country looks to cut emissions and make better use of its coal reserves.

The Central Electrical Authority (CEA) has identified coal-fired plants which are more than 25 years old for retirement in a phased manner on the basis of their "inefficiency and un-economic operation," Goyal said. He did not provide details on the timeframe over which they would be phased out.

Around 78 percent of generated power in India still comes from coal-fired plants, making it one of the biggest users in the world of the dirty and cheap fuel.

Coal-fired plants account for about 195 GW of India's 330 GW of installed power capacity, data on the CEA's website shows.

India, which is also undergoing a program to retrofit several coal-fired plants to reduce emissions, has retired about 4 GW of coal-fired power plants over the last two years.

However, state-run power utility NTPC Ltd plans to invest $10 billion in new coal-fired power stations over the next five years despite the electricity regulator's assessment that thermal plants now under construction will be able to meet demand until 2027, Reuters reported this month.

(Reporting by Sudarshan Varadhan, editing by David Evans)