Micro-hydroelectricity and biogas in China.

 China has the largest hydroelectricity potential in the world. During the “Great Leap Forward” (which started in 1958), there had been plans to build 2.5 GW of Micro-size hydroelectricity plants by 1967, but only about 0.5 GW were completed (Carin, 1969). In a new wave of construction from 1970 to 1979, their number increased from 26,000 to 90,000, with mean size doubling to only 70 kW. Much larger hydro plants in the MW and GW ranges have been built since the 1980s. Many technical and maintenance problems (silting, drought, leaks) with hastily built micro-hydroelectric power plants meant low load factors and relatively high costs. In 2006, China completed the world’s largest hydropower plant, with a capacity of 18.2 GW. From the early 1970s, China had promoted microscale biodigesters running on animal dung, human faeces, garbage and waste water. A 10 cubic metre (m3 ) biodigester was deemed sufficient to provide biogas for a family’s cooking and lighting needs. Some 30,000 were completed by 1973 and 400,000 by 1975. China’s official target for 1985 was 20 million units, but in reality their numbers fell to less than 4 million by 1984, as millions of the units were abandoned owing to lack of the necessary skills for maintenance (ibid.).