This adds to the cost of the disaster in two ways. First, coal! Carbon dioxide. Ugh. The plants are supposed to be integrated gasification combined-cycle (IGCC) stations, which are more efficient ... but it is still coal. (Wikipedia has a nice summary of the technology.)
Second, actual cost. At $3.0 million per megawatt, the plants will be expensive. Japan finished three nuclear power plants in 2004-06. Their capital cost came to $2.0, $2.8, and $2.3 million per megawatt respectively ... rather less than the proposed cost of the coal plants. (Figures fromTable 3 in Yangbo Du and John Parsons, 2009, “Update on the Cost of Nuclear Power,” Center for Energy and Environmental Policy Research WP-09-004.)
Moreover, coal is rather more expensive than uranium. The average landed price in Japan was $106.28 per ton in August 2013. Even if we assume a 50% heat rate (the average for the Japanese coal fleet is 45%) that would translate into a fuel cost of $30.61 per megawatt-hour, against $12 for a nuclear plant.
Tepco says that it uses a 3% discount rate to evaluate projects, which seems rather low (even for Japan) but let’s use it anyway. (It won’t make a difference, since the straight-up capital costs for coal are the same.) Let’s also assume that both a coal and a nuclear plant will last only 25 years. (Nuclear plants will make it to 60, and Japan’s BWR designs are longer-lived than the PWRs common elsewhere.) Add in a cost of $1.2 million per MW for a CCGT plant (they are more expensive in Japan) and a natural gas cost of $16 per MMBTU and you get the following levelized cost of electricity per megawatt-hour:
$52 is a lot higher than the $37 it would cost to get the electricity from nuclear! And that doesn’t take into account that the cost is even lower from Japan’s existing reactor fleet, which is mostly depreciated.
And so, the cost of Fukushima keeps growing, as one of the few countries where nuclear power is economically competitive turns to burning more expensive coal. I find it sad.