Nuclear Phaseout? — A trick in the 15% Scenario

In the previous post, I talked about the three Options for Energy and the Environment presented by the Japanese government. From now on, I want to dig into a little bit deep into the content of the Options.

Although this is not exactly my favorite topic, let me first deal with the issue of nuclear because this is the dividing factor of the three Options and is currently at the center of people’s attention.

As I mentioned in the previous post, there are three scenarios for nuclear’s share in 2030.

  • 0% by 2030
  • 15% by 2030
  • 20-25% by 2030

There are 54 nuclear reactors in Japan (of which, 4 are already to be scraped due to the Fukushima accident). And the current (2010, pre-Fukushima) share of nuclear in electricity is 26.4% (or 30.8% if you exclude cogeneration and onsite generation from the total).

So what do these scenarios tell you?

According to government’s own explanation, the 15% scenario is described as a scenario of gradual phase out of nuclear power plants. The “15%” is said to be a milestone in 2030 when each of nuclear power plants is phased out after 40-year lifetime (this “40-year lifetime” is a new policy that was adopted by the government).

But this is not exactly true. To make a long story short, the only “0% scenario” assumes actual reduction of nuclear power plants and both 15% and 20-25% factually assumes new construction.

There is an interesting slide prepared by the Agency for Natural Resources and Energy (ANRE) [in Japanese]. Below is a rough translation of the table in the slide. The table basically shows the background assumptions for certain % share of nuclear in 2030. For example, to get 13% share in 2030, you need to assume 40-year lifetime, no new additional construction and 70% of capacity utilization rate (load factor).  CUR stands for capacity utilization rate.


Snapshot of Year 2030 Reactor Lifetime Assumption
40 years 50 years 60 years
Elec Generation
Share Elec Generation
Share Elec Generation
(1) No new reactor CUR 70% 130.2 13% 218 22% 283 28%
CUR 80% 148.8 15% 249.2 25% 323.4 32%
(2) One new reactor CUR 70% 139.4 14% 227.2 23% 292.2 29%
CUR 80% 159.3 16% 259.7 26% 333.9 33%
(3) Two new reactors CUR 70% 148.6 15% 236.4 24% 301.4 30%
CUR 80% 169.8 17% 270.2 27% 344.4 34%

What you can see from this table is, if you want to get 15% share, you need to assume AT LEAST either:

  1. 40-year lifetime, no new reactors, 80% capacity utilization rate,
  2. 40-year lifetime, one new reactor, 80% capacity utilization rate, or
  3. 40-year lifetime, two new reactors, 70% capacity utilization rate

However, these assumptions have three problems.

1) even in the case of “no new reactors,” it is assumed to restart the 6 remaining nuclear reactors in the area of Fukushima: Apart from the 4 completely damaged nuclear reactors, Fukushima Prefecture has 6 more nuclear reactors.  2 in the same site with the damaged 4 (Fukushima No.1) and 4 in a different power site (Fukushima No.2)).  You can see a map of the location in page 43 of this document. This is highly unlikely to be accepted by the people in Fukushima.

2) 70%-80% Utilization rates are not realistic: in the recent years, the average utilization rate of nuclear power plants in Japan has been around 65%. Increasing the rate means less time for regular inspection. This is again, highly unlikely to be accepted (nor desirable) in the post-Fukushima context.

3) There may be some overestimation: if you add up all the capacity of nuclear power plants in Japan and do calculations under the same assumptions, the figures for these cases would become a few % lower than the figures above.   For example, if you run the numbers for the first case, it will only produce 14%.

All of the three options assume the reduced numbers of nuclear reactors in Japan compared to the current level but 0% Scenario is the only one that goes in the direction of actual phaseout.