China will plough 2.5 trillion yuan ($493 billion) into renewable power generation by 2020, the country's energy agency says, as the world's largest energy market continues to shift away from dirty coal power towards cleaner fuels.

The investment will create over 13 million jobs in the sector, the National Energy Administration (NEA) said in a blueprint document that lays out its plan to develop the nation's energy sector during the five-year 2016 to 2020 period.

The NEA said installed renewable power capacity including wind, hydro, solar and nuclear power would contribute to about half of new electricity generation by 2020.

The agency did not disclose more details on where the funds — which equate to about $98 billion each year — would be spent.

The investment reflects Beijing's continued focus on curbing the use of fossil fuels, which have fostered the country's economic growth over the past decade, as it ramps up its war on pollution.

Last month, the National Development and Reform Commission (NDRC), the country's economic planner, said in its own five-year plan that solar power would receive 1 trillion yuan of spending, as the country seeks to boost capacity by five times.

The spending comes as the cost of building large-scale solar plants has dropped by as much as 40 per cent since 2010.

China became the world's top solar generator last year.

Concerns about the social and economic costs of China's air pollution have increased as the northern parts of the country, including the capital Beijing, have battled a weeks-long bout of hazardous smog.

Reuters