Biogas: The Future for China’s Livestock Production?

Unlike the highly industrialized U.S. livestock sector, which consists mainly of a small number of large-scale farms, the livestock sector in China is still fairly fragmented, taking mainly three forms. The first is small-scale, household backyard production, which has been the tradition here for thousands of years. Each household raises several head of pigs and some poultry. The second is specialized household and commercial production—whether one specialized farmer or several households keeping hundreds of pigs in one production district. The third is large-scale intensive and standardized production. Large-scale usually means having more than 500 pigs or over 5,000 chickens in one farm.

Although household backyard production still makes up most of the livestock sector, specialized and large-scale production is quickly taking over. In China, large-scale production is favored, and is linked to standardization because it’s considered easier—when compared with scattered household backyard production—to control inputs and outputs, enforce environmental regulations, and control disease outbreaks. This kind of production is not equivalent to the U.S. large-scale, factory-style farming, since the U.S. model of large capital investment and intensive use of land make it impractical for the Chinese.

That technology is a biogas digester. Unlike the typical U.S. way of treating animal waste by discharging it into lagoons and spraying it on fields, China has developed its own way to promote what it calls the “circular economy”—by using biogas.

A biogas digester works by converting animal waste through bacterial decomposition into organic fertilizer (the liquid form of the end product) and gas, under either an aerobic or anaerobic environment. The digester has immediate benefits: organic fertilizer can be used instead of chemicals for farms; and the gas can be used for cooking, heating, electricity generation, or fuel for vehicles.

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China began applying biogas technology in the late 1920s. Biogas facilities were widely and rapidly applied during the late 1960s and early 1970s, but the speed compromised quality, proper regulation, and sound management practices, and the number of biogas digesters that worked was small compared to the number installed. During the late 1970s and 1980s, the Chinese government invested more in R&D for biogas technology and exchanged knowledge with other countries.

By the end of 1997, it’s estimated that 6.38 million household biogas plants and over 600 biogas digesters existed in medium and large-scale farms. Between 2003 and 2009, the government invested 19 billion yuan (approximately $US2.78 billion) in building biogas facilities, so that by the end of 2008 there were 30.5 million household biogas tanks and 2,700 biogas digesters in medium- and large-scale farms.

The government is continuing to increase investment in the technology, shifting the focus from household to medium- and large-scale farms. The Mid- and Long-term Development Plan for Renewable Energy (PDF, in Chinese) has set a goal of having 40 million household biogas plants and 4,700 biogas digesters in medium- and large-scale farms.

Household biogas plants are used only for cooking and heating; medium-scale farms generate electricity, too, but mainly for use in the facility itself. However, three large-scale farms with their biogas facilities are now connected to the national grid.

In spite of the growth of biogas facilities, the proportion of households and farms using biogas digesters remains still low, which may be one important cause for agricultural pollution in China. According to a China Daily report that cites Zhang Qingfeng, a leading water resources management expert at Asian Development Bank, “about 35 million of the 140 million rural households were using biogas digesters by the end of 2008 . . . less than 1% of the 4.2 million large-scale farms for pigs, cattle, and chicken use biogas digesters to dispose livestock waste.” The main barrier is cost.

The government is now paying household farmers about half the cost for installing a biogas digester, though the policy in different provinces can vary. Even so, each household still needs to pay several hundreds or even thousands of yuan compared to simply discharging waste into waterways for free (though some local governments levy strict fines for doing this). Furthermore, although using biogas for cooking and heating may save households some living expenses, using it requires knowledge, additional costs for maintenance, and the application or sale of manure. Some small-scale farms may not produce enough animal waste to produce biogas, and even if they do, maintenance costs and manure may remain an issue. Several households sharing one biogas facility may also cause logistical troubles.

The government is subsidizing medium- and large-scale farms more fully, although the investment remains still too high for an owner worried about turning a profit. One pig farm I visited with around 7,000 pigs in stock and an annual output of 20,000 had a biogas facility that cost 2 million yuan (approx. $US290,000). The farm was a local “circular economy” demonstration site and was getting a lot of government support. However, the farmer had still needed to pay slightly less than half the cost of the facility.

A further issue concerns environmental regulations, such as the installation of biogas facilities, which are always more difficult to enforce on existing farms than new ones. Indeed, some existing farms may avoid the need to invest if they have a good relationship with the local government. For bigger farms, economies of scale may make it more appealing to have the facility and connect it to the grid; however, managing it properly is likely to be challenging, and a government subsidy will most likely still be necessary.

From what I see , I’m quite confident that China will be able to deal with waste from the livestock sector. That said, it requires effective regulation, technical support, and cooperation across different sectors.