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Non-Burning Biogas Power Plant Tested in Kobe
(1/7/2002)January 7, 2002–-On reclaimed land in Kobe, the Environment Ministry is testing a state-of-the-art facility that generates electricity from kitchen waste with almost no risk of dioxin discharge, noise pollution or worsening global warming by carbon dioxide (CO2) emissions.
The facility, located on a 2,000-square-meter lot in the southern part of Kobe's Port Island began a trial operation last September and has drawn attention from municipal governments and businesses across Japan. Up to four groups tour the plant daily.
''This facility has demonstrated a new method of future waste management,'' said Shoichi Noguchi of the ministry's Global Environment Bureau.
Under the system developed by general contractor Kajima Corp. and Fuji Electric Co., garbage provided by six large hotels in Kobe is fermented in a 9-meter-high tank into ''bio gas,'' which mostly consists of methane. The gas is then pumped into a fuel cell after toxic substances are extracted. Hydrogen removed through catalysis is used to generate electricity from the cell, according to the two companies and the ministry.
Environmentally friendly fuel cells produce power through a chemical reaction between hydrogen and oxygen in the air, and emit only water as a byproduct.
The ministry, which built the facility with 480 million yen earmarked under the fiscal 1999 and 2000 budgets, expects it will generate up to 2,400 kilowatts of power daily on 6 tons of kitchen waste. The output is enough to power 240 households.
It also wants to use surplus electricity to power electric vehicles and use excess bio gas in cars powered by compressed natural gas. The facility will undergo a three-year trial period and the ministry will then consider putting it to practical use.
Devices have been developed in Japan to turn kitchen scraps into compost, but most is still usually burned in incinerators. Watery garbage requires much fuel for incineration and may emit dioxins if burned at low temperatures.
Noguchi said the facility's great advantage is that it does not burn waste with oil or other fossil fuels that generate greenhouse gases. It is also quiet because there is no burning, he said.
He emphasized the system converts 95% of the waste into power.
''When sorting kitchen refuse, foreign objects such as knives and bottles are set aside and burned. Sludge and waste water are also generated by the process. Altogether, 5% of the garbage that is put into the facility becomes waste,'' Noguchi said.
To promote use of the facility, costs must be reduced and there must be a steady supply of kitchen refuse. The ministry will try to collect more raw garbage from the six hotels and ask them to provide garbage from more restaurants and parties, he said.
Many municipal governments tasked with waste management are interested in the new system and if it is simplified and becomes available at a lower cost, it can be widely used in urban areas that have stable kitchen refuse supplies from commercial facilities, Noguchi said.
