Renewables are already cheaper than new coal-fired power stations in all major markets, exposing almost a trillion dollars of new investments and denting Australia's coal exports.

Analysis published on Thursday by Carbon Tracker also found that by 2030 at the latest, new wind and solar farms will be cheaper to build than existing coal plants.

New coal fired-plants are already more expensive than renewable energy in all major markets - and by 2030 even existing coal plants will be uncompetitive, a new report finds. Getty

The survey, which tapped International Energy Agency data among its sources, also found more than half of coal-fired power stations were more costly to run than building new renewable energy.

Globally, developers are planning or constructing almost 500 giga-watts of coal capacity at a cost of $US638 billion ($984 billion), investments that could soon be wasted.

“Renewables are out-competing coal around the world and proposed coal investments risk becoming stranded assets which could lock in high-cost coal power for decades," Matt Gray, co-head of power utilities at Carbon Tracker and an author of the report, said.

"It makes economic sense for governments to cancel new coal projects immediately and progressively phase out existing plants.”

Half of Australia's coal plant capacity already costs more to operate than to build new wind and solar, a slightly larger proportion than the US but well shy of the 70 per cent rate in China and 95 per cent rate in the European Union, the report finds.

By 2030, all coal capacity will be uncompetitive with renewables in all markets.

The report's findings hinge in part on deregulated markets that allow developers to make full use of the rapid falls in solar and wind technology.

Gannawarra Solar Farm in western Victoria. Solar panel prices have dived 90 per cent over the past decade. Supplied

Leonard Quong, an analyst with Bloomberg New Energy Finance, said the economics of renewable energy "have undergone an astonishing transformation over the past decade", with new solar modules dropping about 90 per cent in cost while wind turbines are now almost 50 per cent cheaper.

"These cost reductions mean that, today, over two-thirds of the world's population lives in a country where building new renewable energy generation is cheaper than building traditional thermal technologies, like coal and gas," he said, adding that Australia was one of the first countries to pass this economic tipping point about five years ago.

"It's already cheaper to build new wind and solar projects than to operate the country's most expensive coal generators - even though coal fuel prices have fallen by nearly 45 per cent since 2018.

"Based on the economics alone, no new coal projects will be built in Australia unless taxpayers foot the bill, or wear some of the risk."

However, Stephen Galilee, chief executive of the NSW Minerals Council, said the tracker report was "not credible as it does not include any of the significant additional storage costs that wind and solar need to match the baseload reliability of coal-fired power".

"An increased demand for energy will mean NSW export coal will be in strong demand for decades, delivering reliable baseload power across the south-east Asia region alongside renewables."