Tokyo One Chapter Too Early?

While doing the Quest for this week, I chose Tokyo for the "place I've been" to discuss. What's the biggest problem Tokyo faces? Power, I figured. I knew Japan imported almost all of their oil, and that Tokyo was a densely-populated city that uses a lot of electricity. I also knew that Japan's per capita energy consumption was much lower than that of the US. But it occurred to me that might be the wrong measure, so I set out to do a bit of research.

I did some back-of-the-envelope calculations to figure out energy usage per area (from here and here):
US: 3,816,000,000 MW-hr/yr / 9,629,091 km^2 = 396 MW-hr/yr/km^2
Japan: 974,200,000 MW-hr/yr / 377,930 km^2 = 2578 MW-hr/yr/km^2

Japan also is also a very (the most?) economically concentrated country (see 2008 World Bank figures here):
US: $14,204,322M GDP / 9,629,091 km^2 = $1.5M/km^2
Japan: $4,909,272M GDP / 377,930 km^2 = $13.0M/km^2

(Would be interesting to see a ranking of countries by those figures.)

Given that Japan has a large high-tech sector and the third largest national economy in the world, one might expect an overtaxed power grid in Japan to be a problem for the world economy.

Japan imports all of its coal, virtually all of its natural gas, and all but a fraction of a percent of its crude oil (compare to the US, which produces 44% of its own oil consumption and 89% of its natural gas consumption). Of the electricity produced in Japan, 28% comes from nuclear power and 12% from renewable (compare to the US with 20% and 9% respectively). Their nuclear power industry has also suffered from safety concerns and bad PR, such that the country's nuclear generation capacity has dropped over the past decade, though there are still hopes to get capacity up into the 40% range by the end of this decade (not surprising, if you want to maintain that kind of energy density).