Solar energy can “reclaim coal’s footprint” by installing panels on abandoned surface coal mines, which a new report says have enough combined area to host 300 GW of solar capacity.

Amidst conflicts that put solar panels in competition with other land uses like agriculture and nature conservation, a new analysis by Global Energy Monitor (GEM) identified 311 surface coal mines that have been closed in the last five years that cover 2,089 square kilometres. Installing panels over these areas could add 103 gigawatts (GW) of global solar power capacity on “derelict lands.”

The study found another 127 sites where coal mines are set to close by 2030, or within the next five years. Taken together, the closed and soon-to-close mines cover a combined are of 5,820 square kilometres of land that can’t be used for much else. GEM estimates that solar panels covering this total area could deliver 300 GW of capacity.

“Acquiring land for global renewable energy targets has been rife with conflicts among stakeholders and decision-makers, so repurposing degraded lands could provide salient new benefits to former coal communities across the planet,” said GEM researcher Hailey Deres.

The sites identified in the report offer opportunities for solar installations of different sizes. About one-third of the 438 coal mine locations could host smaller, community-scale solar projects. But almost 70% have land areas suited for larger, utility-scale solar developments that exceed 50 MW. More than 200 coal mine sites could each have solar potential greater than 100 MW, and roughly 10% could host solar installations with over 1,000 MW capacity.

Often, these sites have the additional competitive advantage of being located close to electricity grids, reducing the amount of infrastructure needed to connect the electricity they generate to its end uses. The report shows that 91% of recently closed mines are within 10 kilometres of a grid connection, while 76% of mines expected to close in the next five years have grid connections within that distance.

However, grids and connection infrastructure will still need upgrades to accommodate the intermittent and variable generation from solar, rather than the steady, baseload supply typical of coal. Approval to develop solar projects on closed mines will also mean overcoming legal and regulatory hurdles. But GEM’s report says the conversions are possible, noting that 15 countries are already taking steps to install solar over coal mines, though almost all projects are still in early stages.

“The legacy of coal is written into the land, but that legacy does not have to define the future,” said Cheng Cheng Wu, project manager for GEM’s energy transition tracker.

“With the right choices, the same ground that powered the industrial era can help power the climate solutions we now urgently need.”