Japan can triple its renewables capacity and aim to phase out coal power by 2035, a group of companies and nongovernmental organizations has said, urging the government to be more ambitious in accelerating its energy transition.

The nation should recalibrate its national targets and slash emissions by two-thirds by the middle of the next decade, according to the Japan Climate Initiative, a network of banks, universities and companies, including Rakuten Group and Panasonic Holdings.

Japan, the only Group of Seven nation not to have a deadline to phase out use of the dirty fuel, currently uses coal to generate a third of its electricity. It has the potential to increase renewables in its power mix to between 65% and 80%, JCI said.

To reduce greenhouse gases by 66% or more compared with 2013 levels by 2035, the country must fulfill its international commitment as a G7 member to fully or predominantly decarbonize the electricity sector by 2035, the group said in a letter published on its website.

The call comes as the world’s fourth-biggest economy is set to publish its national energy strategy and countries are expected to renew their "nationally determined contributions” on emissions reductions in the run up to the COP global climate summit in November.

In a bid to curb rapidly rising temperatures, global leaders had set a goal to limit global warming to below 1.5 degrees Celsius from preindustrial times under the Paris Agreement in 2015. Despite that, the world looks to only have a slim chance of keeping global warming below that key threshold.