Richard Katz wrote:

"I've seen no evidence that renewables can be geared up at a feasible cost to provide 25% of Japan's electricity in just ten years or even 20 years. A 2010 report of the National Academy of Sciences said that, in the US, non-hydro renewables could conceivably reach 10% of the nation's electricity generation by 2020, if there are sufficient cost reductions that match and exceed cost reductions in other sources, e.g. natural gas. This could conceivably rise to 20% by 2035. Going to 50% or more would require new scientific advances.
The report also notes that past prediction of the penetration of renewables have over-estimated their share. (Executive Summary, Electricity from Renewable
Resources: Status, Prospects, and Impediments, 2010 from, National Research Council/National Academy of Sciences). I don't see why this would be different in Japan. So, I'd like to hear why you think that is the case."

It's hard to come up with "evidence" from the future, so I would prefer to reinterprete this as evidence in the present that points to possible road-blocks in the future. Andrew DeWitt already did a great job providing evidence regarding progress that Germany has already made in increasing its renewable energy electricity production in a very short-time (from under 4% of electricity supplied to well over 20% in only 10 years). That is certainly a benchmark relevant for Japan, as is Denmark, where over 20% of electricity production comes from renewables. I will concentrate on addressing potential roadblocks. As I already wrote, the main obstacle for Japan is political, not technical.

Regarding the study from two years ago that Rick cites for the US, the growth rate estimated for the next 8 years, continued for the following 16, would allow the US to produce more than 30% of its electricity from renewables by the 2030s. Moreover, I have to ask what technological barriers there are that would prevent 50% or all American electricity from being produced by renewables? What technological advances would be needed? Exploitable wind and solar resources alone well exceed total consumption even with current technology (regarding Japan, I already presented data from METI and the Environment Ministry showing this was the case even for Japan). Rather, I would suggest the barriers are mostly political and regulatory. If, for example, the US implemented a Japanese-style feed in tarriff, the expansion of renewable electricity production would be much faster. The same would be true if the US got serious about developing regulations and investments to provide grid access for renewable projects and developing a smart grid and associated storage facilities.

Again, with Japan, what technical barriers prevent Japan from producing 30% of its electricity by the 2030s, if not earlier? This is now the government's target. I would like to see a serious study explain why the government's plan is technically infeasible.
The only barriers I see relate to regulation and ownership structure. What barriers are going to stop the new Feed in Tarriff from prompting entrepreneurs to produce enough renewable energy capacity to meet, and probably well exceed, 30% of Japan's electricity needs by the 2030s? The main bottleneck is ensuring grid access, which is why the EPCOs have to be divested of grid control. The second issue is how storage technology is deployed in reality, which is mostly a regulatory issue. Will renewable energy producers be required to provide storage (e.g. flywheel or hydrogen), will this become the responsibility of the grid owner, or is a market created for companies to specialize in the provision of storage services?

NIMBY issues are a barrier, as objections arise to placing wind turbines on-land, and off-shore in the case of Japan (fishing interests). NIMBY issues are of declining importance in rural Japan where depopulation and declining economies make renewable energy increasingly attractive. I am not aware of any significant NIMBY issues so far regarding solar. If there is the political will, the costs and benefits of wind turbines can be seriously discussed with local opponents. Even with renewables there is often no free
lunch: would local groups rather have a nuclear power plant in their backyard or wind turbines?

Again, the primary barriers to renewable electricity replacing nuclear power are political. That said I will add one caveat: the primary threat to the spread of renewable energy comes not from expensive nuclear power, but from increasingly inexpensive natural gas, although the feed in tarriff offers significant insulation for Japanese renewable energy producers.
Behind the fall in natural gas prices has been a rapid increase in natural gas reserves in the US and elsewhere. Moving forward this significantly eases cost concerns for thermal electric plants and energy security concerns (as long as Japan does not fear dependence on North America). Moreover, it likely that Japan possesses large reserves of natural gas and methane, including hydrates, on the seabed of its vast EEZ (not counting the small portions of that EEZ that are in dispute with China and Korea), an area which is three times that of Japan's land territory.
Consequently, Japan even has the possibility to achieve a measure of self-reliance in natural gas production.
Burning natural gas has essentially no negative impacts on human health (unlike coal in particular), and produces the lowest CO2 emissions of any fossil fuel, although these emissions are not zero.

What this boils down to is that Japan can rapidly (although perhaps not instantaneously) end its reliance on nuclear and promote a rapid expansion in renewable electricity production while using natural gas as a hedge (a hedge I don't think is necessary, but a security blanket nonetheless for the truly risk averse). Thus, the rapid expansion and ongoing technological advancement of renewables plus the large increase in natural gas supplies provide Japan with good reasons and incentives to end reliance on nuclear power.

Paul Midford
Norwegian University for Science and Technology