James Montgomery, News Editor, RenewableEnergyWorld.com
March 23, 2012 | 6 Comments
New Hampshire, U.S.A. -- In the wake of the March 11, 2011, earthquake/tsunami/nuclear disaster, nearly all of Japan's 50-plus nuclear plants are now offline, and soon they all will be dark. That's left a gaping hole in Japan's power generation, just ahead of the traditionally grid-stressing summertime season.
Strict energy conservation efforts have helped soften that blow, and Japan is still figuring out how to responsibly reopen some of its nuclear footprint. In the meantime, renewable energy will be relied upon more heavily to shoulder Japan's energy load, including megasolar plans and wind projects.
Another renewables plan approved by Japanese officials aims to solve two problems in one stroke. The government says it will fund the ramp-up of several biomass plants specifically to process tons of rubble and debris from the disasters. Most of that, an estimated 70 percent of the 22 million-plus-tons in Iwate, Miyagi, and Fukushima prefectures, is wood. Japan's Forestry reportedly has earmarked ¥9.5 billion to cover up to half the costs for building the four 1-5 megawatt biomass plants in Iwate and Miyagi Prefectures. Once they run out of debris from the disasters, they'll switch to processing wood from lumber and paper mills. This waste is reportedly piling up faster than it can be disposed of.
In Fukushima itself, ground-zero for the March 11 nuclear disaster, biomass efforts have progressed even further. The prefecture has just over 2 million tons of debris from the disaster, only around 5 percent of which has been processed.
First Energy Service Co. (FESCO) says it is now accepting debris from the quake that actually contains radiation. (Here's FESCO's brief in Japanese, which the Nikkei summarizes in English.) The 11.5-MW biomass plant in Shirakawa uses around 380 tons of debris per day, and is now starting to accept up to 20-30 tons per day of "tainted" debris, which it will decontaminate to >100 becquerels/kilogram (Bq/kg) of radioactivity using high-pressure hoses and other methods, reports the Nikkei. FESCO claims "practically no" radioactive substances will be released into the atmosphere during incineration.
The leftover ash residue, though, will have highly concentrated radioactive substances (several thousand Bq/kg). Government rules say ashes with up to 8,000 Bq/kg can be buried, while material tallying 8,000-100,000 Bq/kg must be secured and buried in concrete containers. The prefecture apparently has agreed to take the ash and figure out how to dispose of it, so FESCO is moving ahead.