Photo/IllutrationAn anti-nuclear power gathering is held in Kashiwazaki, Niigata Prefecture, on Sept. 16. (The Asahi Shimbun)

The Environment Ministry was forced to retract its trial calculation that the ratio of nuclear power generation to Japan’s total electricity generation will be less than 10 percent in fiscal 2050.

The ministry made the retraction in February in response to backlash from the Ministry of Economy, Trade and Industry, which is supervising the electric power industry, several sources of the two ministries said.

At the time, the economy ministry was proceeding with a revision of the government’s basic energy plan.

It apparently feared that the trial calculation could influence discussions on the future ratio of nuclear power generation, the sources added.

“We didn’t put pressure (on the Environment Ministry),” an economy ministry official said.

However, an Environment Ministry official said, “We couldn’t help but retract (the original trial calculation).”

After the retraction, the contents of the basic energy plan were decided as had been worked out by the economy ministry and were approved in a Cabinet meeting in July.

The Abe administration regards nuclear power generation as “an important baseload electric source” and is promoting the restarts of nuclear reactors.

Under the policy, the economy ministry has apparently adopted a stance of concealing data that is inconvenient for the administration.

The Asahi Shimbun obtained the trial calculation, which was shown to the economy ministry by the Environment Ministry.

According to the estimate, the ratio of nuclear power generation to Japan’s total electricity generation will be 21 percent in fiscal 2030 in accordance with the Abe administration’s policies.

The ratio will decrease to 11 to 12 percent in fiscal 2040 and to 7 to 9 percent in fiscal 2050.

In addition, the ratio of renewable energies will increase to 57 to 66 percent in fiscal 2040 and further to 72 to 80 percent in fiscal 2050.

The Environment Ministry compiled the trial calculation by setting up a team with Mitsubishi Research Institute Inc. and experts to examine measures to reduce greenhouse gases.

In the trial calculation, the team assumed that renewable energies will be introduced as much as possible.

The estimate was done under the premise that no new nuclear power plants will be constructed and no new nuclear reactors will be built on the grounds of existing nuclear plants.

Another assumption was that nuclear power generation capabilities will be half those of a scenario in which all existing nuclear reactors will be operated for 60 years.

The premises were based on the current situation in which electric power companies are facing difficulties restarting existing reactors, constructing new nuclear plants and building new reactors in the existing nuclear plants.

On the other hand, the economy ministry planned to write in the basic energy plan that the ratio of nuclear power generation will be 20 to 22 percent in fiscal 2030 and not to mention the ratio in fiscal 2050.

The ministry also planned not to touch on construction of new nuclear plants or the building of new reactors in the existing plants so that the possibilities remain open for their construction in the future.

According to the sources, the Environment Ministry initially planned to release the trial calculation in a council meeting to be held Feb. 20.

When the ministry explained to the economy ministry about the trial calculation immediately prior to the meeting, the economy ministry disagreed on the ratio of nuclear power generation in 2050.

“Is there any basis? I think that there is no reason (for it),” an economy ministry official said.

In response, the Environment Ministry suspended the announcement of the trial calculation. It conducted one again based on data on Japanese nuclear power generation that were compiled by organizations, such as the International Energy Agency, as proposed by the economy ministry.

The new trial calculation did not show the future ratio of nuclear power generation and described power generation amounts.

When calculations were made based on the amounts, it estimated that the ratio of nuclear power generation will be 13 to 23 percent in fiscal 2040 and 13 to 24 percent in fiscal 2050. Those figures are higher than those described in the original trial calculation.

The new calculation was not shown to a council meeting but was posted on the Environment Ministry’s website as the result of research by the Mitsubishi Research Institute dated March 30.

(This article was written by Tsuneo Sasai and Rintaro Sakurai.)