The study by the non-profit group, which promotes a low-carbon economy, comes as top leaders prepare to gather in western Japan for a meeting of G7 nations on May 26 and May 27. Environmental groups have used the lead-up to the gathering to increase pressure on Japan to review its policy on coal power.

Japan is the only G7 country seeking to build new coal-power plants.

Though many developed nations are in the process of shifting away from coal, the fossil fuel was identified in a recent policy statement as an important component of the country’s energy mix.

“An additional 4 gigawatts of proposed new coal-plant capacity has been cancelled, leaving Japan as the sole G7 country actively seeking to build new coal-power plants,” author Chris Littlecott wrote.

Since 2014, Tokyo has been encouraging a major expansion of coal-fired generating capacity. Currently, the country has four coal plants with a combined capacity of 1.9 GW under construction, but there are another 49 plants in various stages of planning. Together, they would add another 28 GW of capacity to Japan’s power system, another study released earlier this month shows.

The global coal industry has been battered in recent years by competition from cheap gas, declining demand from China and clean-air regulations that have raised costs for burning the fuel.

Concerns about carbon emissions from power stations coupled with a deep global glut in thermal coal production has resulted in a lengthening line of mine closures and production cuts, particularly in North America and Indonesia.