Sunday, October 4, 2009

CASE STUDY: China Produces Energy From Waste

By Allard Nooy

China is creating unprecedented wealth for an unprecedented number of people. At the same time, China is also creating an unprecedented volume of rubbish. The country already produces more rubbish than any other nation, and every year Chinese cities generate one-third of the total amount of rubbish produced in the world.

Annually, China throws away some 190 million tonnes of municipal solid waste (MSW). Approximately five per cent gets recycled and less than ten per cent is used to produce Energy-from-Waste (EFW) also known as Waste-to-Energy (WTE), while more than 80 per cent of this waste ends up buried in landfills. This is creating a potential crisis that government is working hard to avoid by implementing integrated waste management plans that include EFW facilities.

These efforts reflect a growing global chorus that is calling for additional economic investment in the EFW industry. As noted by the World Economic Forum in its "Green Investing" report issued earlier this year, EFW can be an important contributor to a carbon-neutral infrastructure. Similar sentiments were expressed in 2008 at the Global Roundtable on Climate Change: "... efforts to reduce global emissions of methane from landfills should be expanded, including increased use of waste-to-energy facilities..."

To address China's waste challenge, communities (as part of an integrated waste management system) are being encouraged to reduce, re-use, recycle and rethink their waste disposal options to recover energy from waste. While recycling is a preferred first step in the waste management process, not all waste can be recycled. And, after recycling, there are only two options for disposal: bury waste in a landfill, or burn it. As old landfills expand or new landfills are developed, the amount of open space that is destroyed will increase.

In addition, decomposing rubbish creates methane gas - a potent greenhouse gas that is over 20 times more effective in trapping heat in the atmosphere than carbon dioxide (CO2). Methane has been identified as a significant contributor to global warming. When a landfill is capped, methane can still be released for years, although the land has limited uses. Landfills also release hazardous air pollutants (HAPs) which are contained in landfill gas. Ground water can also become contaminated from landfill leachate.

What Exactly Is Energy-from-Waste?

EFW is a process where MSW (i.e. household rubbish) is combusted at high temperatures in specialised combustion units and reduced to ten per cent of its original volume. The heat generated from these combustion chambers heats up water in steel tubes that form the walls of the combustion chambers. The water is turned to steam and sent through a turbine that continuously generates electricity.

EFW facilities use state-of-the-art technology including sophisticated air pollution control systems. Combusting one tonne of waste in an EFW facility prevents the equivalent of one tonne of CO2 from entering the atmosphere through the burning of fossil fuels to produce the same amount of electricity, and the decomposition of MSW in landfills. EFW facilities also recycle metal that would have otherwise been dumped. Increasing local metal recycling also offsets greenhouse gases as it reduces the need to mine for virgin metals.

China faces an acute electricity shortage which is likely to persist for the foreseeable future. The construction of additional EFW facilities will only play a relatively small part in China's energy mix, but will be an important component in diversifying the number of energy sources that the country relies upon. In addition, EFW facilities operate 24 hours a day, seven days a week, making them the most continuously reliable source of renewable electricity generation. The energy output of these facilities can help replace base-load coal and gas-fired power plants as an energy source. For every tonne of waste processed at an EFW facility, one barrel of oil would not need to be imported, or a quarter-tonne of coal would not have to be mined.

This article was written by Allard Nooy, for the China market news magazine, BusinessForum China. With stories and analysis ranging from China sourcing to China investments, Business Forum China is the source of all business news in China.

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