Wales could generate 880 gigawatt-hours of electricity and earn an estimated 19.5 million British pounds ($26.3 million) by 2050 by capturing methane from abandoned coal mines, Ember analysts said in a Tuesday note.
Recovering abandoned mine methane would cut emissions, create a local energy source and reduce risks linked to uncontrolled gas migration while supporting former coal-mining communities.
Direct measurement and recovery projects can prevent methane, which is about 82 times more potent than carbon dioxide in the short term, Ember said.
Wales produces roughly half of the UK's modeled abandoned mine methane emissions, yet the country lacks dedicated reporting and still relies on estimates rather than direct monitoring of mine-shaft emissions, Ember added.
South Wales contains four of the UK's 10 highest-emitting abandoned mine areas, reflecting the methane-rich nature of the region's anthracite coalfields, according to Ember.
Welsh coal mines contain about 168,000 tons of methane, but Wales has no operating recovery projects despite evidence that the technology already works elsewhere in the UK, the report said.
Across the UK, 16 active abandoned mine methane facilities are expected to export 100 GWh of electricity and generate 2.3 million British pounds in gross profit during 2025, highlighting the scale of the opportunity.
Ember said inadequate data and policy shortcomings have slowed project development, while operators argue that a lack of accurate site-level measurements makes it harder to estimate output and identify additional methane resources.
Developing abandoned mine methane projects requires policy support because complex mine ownership structures, licensing issues and volatile energy prices can make projects difficult to finance and operate, Ember said.
The report urged Wales to require direct, site-level methane measurements from closed and abandoned mines through standardized monitoring programs to improve emissions transparency and identify mitigation opportunities.
Ember also recommended a framework to progressively eliminate routine venting and flaring of abandoned mine methane, aligning Welsh policy with international standards, including principles reflected in the European Union's methane regulations.
To improve project economics, the report called for targeted incentives such as subsidies, tax credits and long-term price guarantees, citing successful approaches in Germany and France that have helped attract investment in mine-methane recovery projects.