Though only a tenth of existing coal plants are scheduled to shut down by 2030, more could close if efforts are made to identify opportunities, the Institute for Energy Economics and Financial Analysis (IEEFA) said.
"The key problem here is a lack of a pipeline of well defined, contracted, bankable coal-to-clean transactions," said Paul Jacobson, lead author of the report.
Around 15.5 billion metric tons of carbon dioxide are generated every year by 2,000 gigawatts of coal power. The International Energy Agency says emissions need to reach zero by 2040 if temperature rises are to remain within the threshold of 1.5 degrees Celsius.
But decommissioning is costly, especially if plants are still paying off debt or tied to power purchase agreements (PPAs) that commit them to supplying electricity over decades.
Governments have been looking for solutions to pay for the transition - including the Asian Development Bank's Energy Transition Mechanism - but only a small number of projects have gone ahead.
The 800 viable transition targets identified by IEEFA include around 600 built thirty years or more ago, many of which have repaid debts and are no longer tied down by lengthy PPAs.
With profit margins for renewables now sufficient to cover the cost of replacing coal plants, decommissioning the remaining 200 plants built between 15 and 30 years ago could also be affordable, though obstacles remain, including fossil fuel subsidies that inflate an asset's value.
Decommissioning newer plants will be a bigger financial challenge, particularly in countries still building fresh capacity, including Vietnam.
Environmental groups have criticised transition financing for paying polluters not to pollute. Jacobson said "guardrails" were required to avoid creating perverse incentives.
"Companies that continue to build new coal power plants while seeking concessions to build renewable energy should not be allowed to use that to benefit from this," he said.
