Municipal Solid Waste (MSW) Biogas Potential in China

Much Biogas from Agricultural organic waste is utilised in China already. Now China will seek to develop renewable, and highly sustainable, energy for the nation from its Municipal Solid Waste.

China is famous for its long-standing ability to use organic wastes for biogas production in the agricultural and small community sector. It now plans to build upon this expertise to maximize the renewables potential across the nation. For both agricultural Anaerobic Digestion applications, and for Solid Waste Management biogas applications, development of more sophisticated technologies for larger units is thought to be needed.

Table 3  MSW/BMW and food waste biogas plants currently under consideration in China

Note: The table above is an extract from; Biogas from Municipal and Agricultural Bioorganic Waste: Renewable Energy for China, Bernhard Raninger, ZHAO Youcai , Jl Rong, LI Aimin , Werner Bidlingmaier , LI Rundong , LI Ronggang; International Symposium MBT 2007    
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As early as the end of the 19th century, simple biogas digesters appeared in southern China. In 1932 the first biogas company was opened in Shanghai with branches along the Yangtze River and in the southern provinces. China supported mass adoption of biogas in 1975 under the slogan "biogas for every household". The Chengdu Biogas Research Institute (BIOMA) was founded in 1979 to disseminate this know-how even on international level.

The application of the home-grown biogas technology is still today mostly limited to small-scale local or community anaerobic digesters in rural areas in the south and south-west of China. Applications of this technology at a large-scale is rare, However, this is due to change now, as under the national renewable energy legislation the targets are changing and the primary aim of these plants is moving away from the environmental benefits of digestion to renewable energy production.

The overall Chinese energy policy target is to achieve a renewable energy supply of 16% in 2020, starting from 7% in 2004. Biogas will contribute with 24bn nm3 biogas (grid-connected), deriving from all applicable biomass sources. This is at least three times more biogas production compared to the 7.3bn nm3 generated in.

Within China 'renewables' derived energy including hydro-power accounted was reportedly 7% in 2005 within which the biomass contribution was insignificant. However, by 2010 a rise to 10% is planned, with biomass accounting for 18.4% of the total renewable energy supply.

By 2020, 16% of power is planned to be from renewables, with 18.5% of the entire energy demand in 2020 coming from biomass (agriculture, industry, MSW, sewage sludge, small- and large-scale units, landfills etc).

Landfill Gas Extraction

Regarding biogas generation from MSW the authorities will give a high priority to landfill gas recovery CDM projects, especially for landfills closing soon, and which will produce high gas yields, before there is large scale recycling to remove the landfill gas creating organic materials. Their aim is to follow the success in many industrialised countries which routinely utilize the energy from landfill gas.

Energy from waste schemes form part of the 2020 overall biomass electrification target of 30 GW.

Biogas from Small-scale Household Digesters

The small-scale urban household biogas digesters are well established and politically strongly supported in the south western rural areas of China and the number of household biogas digesters is growing for some million units every year. In 2003 8m units (typical size 8 to 10 m³) were in use.

By 2005 in China, about 10% of the rural population was already producing 5.5bn nm³/a biogas from 15m units. 56m digesters will be operated till 2020 and 20bn nm³/a of biogas will be produced for decentralised energy supply (cooking, lightning), and will make these areas widely independent from central energy supply systems.

Furthermore water and soil pollution problems from liquid and solid organic waste disposal are widely solved. This is an additional motivation to develop further this sector based on the 'National Biogas Construction Plan of the MOA 2003.

Middle and Large-scale Agricultural and Agro-Industrial Plants

Since 2001, the Chinese government has been emphasizing the importance of biogas technology development and its implementation for agricultural production, rural energy supply, and environmental protection, and finally on the improvement of the living conditions of the rural population.

Since that time 0.35bn EUR has been invested into biogas technology dissemination. 4,000 middle- and large-scale biogas plants were built mainly at pig, chicken and cattle farms, and the total biogas output is about 0.34bn nm³/a, from which a part is used for electricity production (400m kWh per year in "island" mode, no grid-feed-in) and the rest is supplied for cooking to 1.4m households.

Industries, such as the sugar industry may generate electricity from waste (-water). For example more than 800 MW are generated in the sugar-growing provinces of Guangdong and Guangxi alone. Another example is the alcohol production industry, such as the distillery in Nangang (Henan), which supplies 20,000 households with biogas. The Chinese agricultural biogas plant potential includes at least 14,000 intensive livestock farms with more than 100 livestock units (1 LSU = 500 kg of animal live weight) each.

In the 11th 5-Year Plan period, the investment from the Ministry of Agriculture in biogas plants is expected to be 250m EUR per year, so do not underestimate the power of China and renewable energy use in this technical area.

With acknowledgements to Biogas from Municipal and Agricultural Bioorganic Waste: Renewable Energy for China, Bernhard Raninger, ZHAO Youcai , Jl Rong, LI Aimin , Werner Bidlingmaier , LI Rundong , LI Ronggang; International Symposium MBT 2007    
www.wasteconsult.de