BEIJING - China's state planner stressed the key role of coal in a report to parliament on Sunday, saying it would strengthen the supporting role played by the fuel and advance production as it seeks to boost power generation.

The world's second biggest economy relies on coal to generate about 60% of its electricity but it has significantly boosted use of natural gas and renewable energy in recent years as it seeks to lower its carbon emissions.

However, fluctuations in output from renewable plants as well as the impact of drought on its hydropower generation has previously resulted in power outages, leading policymakers to lean on coal to shore up the country's baseload supply.

The National Development and Reform Commission noted there was a need to improve its energy security in extreme weather events.

It added that it would "strictly control the expansion of projects to replace coal with natural gas".

(Reporting by Andrew Hayley; Editing by Tom Hogue & Simon Cameron-Moore)