Japan is reviewing its future energy sources as climate advocates call on the government to make it easier for the renewables sector to access the power grid.

Renewables, including solar and hydropower, are projected to make up between 22% and 24% of the energy mix in 2030, according to an official blueprint released two years ago. That compares with 26% for coal and 27% for liquefied natural gas.

But doubts have been raised about whether the government’s 20-22% nuclear power target is realistic, given that most of the country’s reactors remain offline pending safety checks and community challenges after the Fukushima triple-meltdown of 2011.

Kimiko Hirata, international director of the Japanese climate advocacy group Kiko Network, said the use of fossil fuels had increased because of the idling of nuclear plants.

An industry ministry panel began talks in August on reviewing the country’s basic energy plan, with a decision due in the first half of next year.

Increasing the 2030 share for renewables would send “a good political signal” to the market, Hirata said. She added that the Kiko Network’s immediate focus was on stopping a raft of proposed new coal power projects because of their potential to lock in increased fossil fuel usage.

“There’s lots of new coal power projects – one third of them are under construction already and the rest of them are at a fairly late stage of the environmental impact assessment,” she said in an interview.

“If we cannot stop them … that will lock in the electricity output by 2030. So, I think what is the determining factor for the 2030 outlook is whether we could have a good incentives to the renewables in one or two or three years and then how we can slow down or stop some of the new coal power projects in two or three years.

“If we cannot be serious about the next three years’ policies then the government and also businesses will be in a quite difficult position to reverse this track.”

Hirata noted that power grid rules gave existing major utilities strong control over whether to allow extra renewables capacity into the network.

December 11 marks the 20th anniversary of the adoption of the Kyoto Protocol, a landmark climate agreement that committed 38 mostly developed countries including host nation Japan to binding cuts to their greenhouse gas emissions.

Analysis shows that Japan, which promised to cut emissions by 6% below 1990 levels in the period 2008 to 2012, became one of the major players in carbon trading, alongside the European Union and New Zealand. It “had to resort to Kyoto flexibility mechanisms” by buying international credits to meet its commitment, according to a paper published last year.

“The fact that Japan managed to comply despite the total closure of its nuclear stations after the Fukushima disaster, just under two-thirds of the way through the commitment period, remains testament to its large compliance effort before that,” University College London professor Michael Grubb wrote in an editorial for the Climate Policy journal.

Hirata, who attended the Kyoto talks in 1997 with the US environmental group the Climate Institute, said there were active debates about climate policies in Japan in the first 10 years after the deal.

But she said it was “very disappointing” that Japan ultimately did not sign up to a second round of Kyoto commitments for 2020. The government pointed to the refusal of the United States and China to be bound by targets to justify its stance.

Professor Jumpei Kubota, the deputy director general of the Research Institute for Humanity and Nature in Kyoto, said the earthquake and tsunami devastation had a major impact on the country’s political priorities.

“From 2011, most Japanese people thought that the revival from the earthquake was the most important priority,” Kubota said in an interview.

Ahead of the Paris climate summit in 2015, Japan set a voluntary target of reducing greenhouse gas emissions by 26% below 2013 levels by 2030.

“Climate change is a global challenge,” the Abe government said in its submission to the Paris process. “To solve the problem, it is essential to establish a fair and effective new international framework which is applicable to all major parties.”

Japan has has since ratified the Paris agreement. However, the 2030 target has been criticized by the Climate Action Tracker (CAT), an analysis service run by three climate research bodies.

CAT said: “We rate the target ‘Highly insufficient,’ meaning that if all countries were to adopt this level of ambition, global warming would likely exceed 3-4 degrees celsius in the 21st century.”

Japan, according to Hirata, is still debating whether it should prioritize the climate or the economy. She said think the government and industry should take a longer-term perspective and embrace green businesses, technologies and services.

Asked to reflect on the enduring impact of the Kyoto Protocol, Hirata said it had “created the basic foundation to tackle climate change” and paved the way for further action such as the Paris Agreement.

“I think that the Kyoto Protocol was one of the strongest outcomes that could be possible at that time because it could collapse and also until the very, very last moment we didn’t know what the outcome would be,” she said.

“It agreed on the mandatory targets and also it could send a strong political signal that developed countries have to reduce their greenhouse gas emissions otherwise the problem of the global environment cannot be solved.”

Hirata added: “Of course there are lots of loopholes and there are lots to be fixed afterwards, but I think at that time the political momentum was very, very high and politicians and heads of delegates could not ignore the momentum.”

Kubota, meanwhile, said the fact that global emissions had increased showed that “in this sense the Kyoto Protocol failed.”

“But this is not the important point I think,” he said.

“The significance of the Kyoto Protocol is it was the first step all over the world of tackling global warming issues … I would say that all of the action and discussion against climate change started from the Kyoto COP3 [third Conference of the Parties].”