[Special Contents] Key Issues to Address in Japan's Strategic Energy Plan
Since the Strategic Policy Committee began considering revisions to Japan’s Strategic Energy Plan, one prominent theme in every document and discussion thus far has been the emphasis on the importance of nuclear power in the pursuit of decarbonization. A numbers of opinions are expressed one after another for the use of nuclear power, making statements such as “In order to decarbonize Japan’ s power supply, the first key factor is the utilization of nuclear power,” “The issue of nuclear power is crucial for Japan when considering NDC going forward,” and “We are acutely conscious of the need for nuclear power, both in terms of price and power generation efficiency”.
It is true that nuclear power generation emits almost no CO2, and it is therefore not surprising that some are advocating its use as a decarbonized power source. However, what is not clear from the data presented by the Ministry of Economy, Trade and Industry (METI) and in each discussion is that even if nuclear power is utilized, it is only capable of supplying 10% of total electricity needs at best.
Even if Nuclear Power were Tripled, It Could Only Supply 10% of Electricity Needs
At the Strategic Policy Committee meeting held on 15 May, METI, in its explanation of the movements towards decarbonization efforts at COP28, stated, “In addition to efforts to triple renewable energy and double the energy efficiency improvement rate, for example, a declaration to triple nuclear power has also been announced.” In response to this explanation, a committee member commented that the world is now on a path toward expansion of nuclear power.
The Declaration to Triple Nuclear Energy is a joint declaration announced by 22 countries, including Japan, during COP28 to “advance a global aspirational goal of tripling nuclear energy capacity from 2020 by 2050.” While METI explains that this goal is in parallel with targets for tripling renewable energy and doubling the energy efficiency improvement rate, the goals for renewable energy and energy efficiency are targets agreed upon by all participant countries and included in the COP28 resolution, while tripling nuclear power is a voluntary goal agreed upon by just 22 of the nearly 200 countries participating in the COP28.
Although it is somewhat disingenuous not to explain these differences, another, more fundamental issue that has been omitted is that even if global nuclear power generation were to be tripled from 2020 levels by 2050, this would only be enough to supply approximately 10% of electricity demand in 2050.
The International Energy Agency’s (IEA) net-zero scenario assumes that total global electricity generation in 2050 will increase to 76,838 TWh, 2.6 times the 2022 level. Of this total, nuclear power generation accounts for 6,015 TWh, equivalent to just 7.8% (Figure 1). Under the IEA scenario, nuclear power generation capacity in 2050 is projected at 916 GW, which would be 1,239 GW1 if tripling of nuclear power capacity is successfully achieved. Assuming that the total amount of power generated will also increase proportionally, this would amount to 8,136 TWh, which is still equivalent to only 10.6% of total power generation in 2050.
The declaration signed by the 22 countries describes the tripling of nuclear power by 2050 as an “aspirational goal.” Indeed, this goal is certainly ambitious given the current stagnation in the construction of new nuclear reactors. However, even if this ambitious goal is achieved, nuclear power would still supply just 10 percent of total power requirements.
Figure 1: Power Supply Mix Under IEA’s Net Zero Emissions by 2050 Scenario
For Japan, Even 10% Supply is Difficult to Achieve with Nuclear Power
As the above is a discussion of the world as a whole, some may reply, “Yes, but the situation in Japan is different.” In that case, let us look at the situation in Japan based on the materials presented by METI to the Strategic Policy Committee on 8 July 2024. The red arrow has been added by the author and depicts the capacity of Japan’s reactors that are currently in operation (the red shaded area of the figure), drawn at the level of their installed capacity. This amount is slightly more than 10 GW. This line passes above the light green shaded area in the figure after 2055. This light green area represents the capacity estimated by the government based on the assumption that existing nuclear reactors will be fully utilized, indicating that by the 2050s it will fall to the same level as today. An installed capacity of just over 10 GW is only enough to supply approximately 6% of the current demand for electric power. If demand for electric power increases through to 2050, as has been widely suggested in the Committee’s discussions, if the total power demand were to rise by 40%, for example, nuclear power would account for around a mere 4% of the power supply.
Furthermore, the capacity assumed in this scenario is based on a highly optimistic outlook, assuming that all reactors that have not yet even applied for restart, or whose applications are still under review and may or may not be approved, will be in operation, and that these reactors will receive permission to operate for a period of 60 years.
One can anticipate the argument, “This is exactly why we need to build new nuclear reactors.” In fact, this is likely the discussion that METI intended to elicit when it presented this figure. According to government documents, it will take 20 years to build new nuclear reactors. This is not quick enough to reduce emissions by 2035 or 2040—the timeline necessary to avert a climate crisis. Furthermore, there is still no viable method for disposing of radioactive waste, meaning that nuclear power cannot be considered a sustainable power source.
Figure 2: Projected Nuclear Power Generation Capacity
with red arrow added by the author
English translation by Renewable Energy Institute
Another problem is who will bear the massive construction costs. A new study of the cost of electricity generation by power source has been launched. The previous estimate for the cost of nuclear power, more than 11.5 yen/kWh, was based on the cost of constructing the latest nuclear reactors in Japan (those which commenced operation between 2005 and 2009), such as the Unit 3 reactor at Tomari Nuclear Power Plant. Compared to the 480-billion-yen cost of installing 1.2 GW in generation capacity at the facility, the innovative light-water reactors envisioned in Japan’s development of new nuclear reactors would cost three to four times as much to build as those in the UK, France and other examples. This raises the question of whether there are operators willing to finance and construct such a huge investment, and even if such reactors could be constructed, the cost of power generation would be high at approximately 17 to 20 yen/kWh.
In order to supply 10% of Japan’s electricity via nuclear power in the 2050s, when decarbonization should be achieved, these challenges must be overcome and the construction of more than 10 reactors with a capacity of 1 GW or more must commence within the coming 10 years or so. After all this effort, this amount would be barely enough to supply 10% of Japan’s total electricity needs. What should be done about the remaining 90%?
Let’s Have a Deeper Discussion About Renewable Energy
Take another look at Figure 1. The IEA has positioned renewable energy sources, primarily solar and wind power, as the greatest source of electricity supply in 2050. The IEA assumes that 89% of electric power will be supplied by renewables (incidentally, although not clear in the above figure, the IEA projects that thermal power with CCS will account for only 1%, and hydrogen and ammonia power generation will account for only 2%).
It is fair to say that there is now a common global understanding that about 90% of electric power in the decarbonized era will be generated from renewable energy sources. Judging from the materials and discussions of the Strategic Policy Committee, it appears that the committee does not share this common understanding. In fact, the Green Growth Strategy formulated by the Japanese government as part of the discussion on the previous revision of the Strategic Energy Plan assumed that even in 2050 renewable energy would remain at 50–60% of total energy generation.
It is only natural to discuss nuclear power at the Strategic Policy Committee, and zero-emission thermal power should also be discussed. However, there should be more time dedicated to a more comprehensive discussion of what policies are necessary to expand renewable energies, which should supply the vast majority of decarbonized power.
This is not just an issue of the Strategic Policy Committee’ s time allocation. Many staff at METI, the Ministry of the Environment, and other government agencies are working diligently to expand solar power, wind power, and other renewable energy sources. However, is the government as a whole committing human resources to the expansion of renewable energy on a scale appropriate to its role these energies will play in supplying 90% of the electric power in a decarbonized society?
There are a variety of challenges involved in expanding renewable energy. However, there are already many outstanding cases throughout Japan where these challenges have been overcome, whether with regard to regional coexistence, handling output fluctuations, or recycling solar panels. Government ministries and agencies should focus on collecting such examples, extracting lessons from them, and disseminating this knowledge throughout the country.
From June to July, companies participating in RE100, the Japan Climate Initiative (JCI), and the Japan Climate Leaders Partnership (JCLP) issued a series of messages advocating a major expansion of renewable energy in Japan. Driving this movement is a serious sense of crisis over the slow pace of renewable energy expansion in Japan. Although the share of renewable energy among total electricity generation in Europe as a whole exceeds 40%, and in Germany it will reach 57% during the first half of 2024, the share of renewables in Japan is still only slightly above 20%. If this trend continues, companies operating in Japan will be unable to compete in the global market. What such companies are seeking is renewable energy, not nuclear power.
[Special Contents] Key Issues to Address in Japan's Strategic Energy Plan
- 1In our calculations, we have substituted the figure of 413 GW for nuclear power generation capacity in 2021 shown in the Net Zero Emissions by 2050 Scenario in the IEA’s World Energy Outlook 2023 (Table A.3c) for the 2020 value.
