by Jiang Gaoming
Mobilizing farmers to use readily accessible, traditional bioenergy sources -- like straw -- may go a long way toward helping the country reduce its carbon footprint.
Coal-mining efforts have recently been shifting from China’s northern Shanxi province to an even more vulnerable ecosystem: the grasslands of Inner Mongolia. Many worry that if this area becomes the next big provider of energy and chemical products, large amounts of its natural resources will be destroyed beyond the point of restoration, as we have seen in Shanxi. We must remember that no amount of money can replace the soil carried off by sandstorms.
China’s population is mainly rural, and if that population (all 800 million of them) were to realize their full potential for consumption, we will have no way to control continually increasing greenhouse gas emissions. Many wealthy farmers are already using energy-hungry appliances such as air conditioners, refrigerators and microwave ovens, as well as coal for heating and cooking. Yet, they typically ignore the traditional bioenergy sources at their doorsteps -- like straw – by simply burning them off in the fields.
To break out of the vicious circle of using fossil-fuel energy, China must shift its reliance to clean energy sources such as bioenergy, solar power and wind power. Rural communities have the means to contribute to this transformation by developing their own energy, which would reduce their toll on their immediate environment and decrease their collective greenhouse gas emissions.
So what if the millions of villages in China were mobilized? For answers, let us look at the experimental data collected by the Institute of Botany at the Chinese Academy of Sciences and Shandong Agricultural University.
The experiment entitled “Using straw as livestock fodder to promote circular energy use in rural areas” was carried out in the village of Jiangjia in Shandong province. The village is home to 923 people, and has 68 hectares of land – an average of 1.097 mu (.073 hectares) per person. Farming is the main industry in a typical village. The experiment was aimed at making full use of the straw that farmers discard.
This straw fodder can be fed to cows, thus turning straw into dung. The dung could then be converted into methane gas for energy and organic fertilizer, which could replace 50 percent of chemical fertilizer use. Energy for heating and cooking would come entirely from methane gas, replacing coal, natural gas and electric ovens. This improvement would make the villagers self-sufficient in energy, with a small surplus that could be sold to urban areas.
In 2005 and 2006, the village had only two or three cows. Since the study started in 2007, the village has raised and sold 50 head of cattle. The village currently has 99 cows in the cattle pens, and by 2009 may have raised a total of 200. With the help of the experts, the village has increased its stock of cattle fifty-fold. These animals have been fed almost entirely on previously discarded straw, with only 10 percent of their fodder coming from purchased grain.
Using dung as an energy source has allowed the researchers to persuade the county agricultural authorities to install methane generators in 100 households, with 93 installations already complete. In addition, 30 households installed the equipment at their own expense. This brings the total installations to 123 households, which signifies that more than half of the entire village are now producing methane.
Each household produces an average of 1.3 cubic meters of methane per day. Using methane for cooking saves 339 kilograms of coal annually, reducing carbon dioxide (CO2) emissions by a little over one tonne. The entire village saves 41.6 tonnes of coal, reducing emissions by 133 tonnes. International carbon prices put the cost of one tonne of CO2 emissions at US$200. Using these calculations, this project has earned 244,000 yuan (US$35,882).
China has 3.2 million villages. If similar methane projects were undertaken in each one, 853 million tonnes of CO2 emissions would be avoided every year (current annual emissions are seven billion tons annually). If one takes into consideration the 50 percent reduction in use of chemical fertilizer and the carbon returned to the fields via organic fertilizer, the emission reductions are even larger.
During the summer, more methane was produced than could be used. If this gas was collected and compressed, it could be used in place of liquefied natural gas to supply the village’s energy needs during the winter. Unfortunately, there currently is no investigation of the potential for reduced carbon emissions in Chinese rural areas, and carbon trading in these locations is non-existent. This study shows that there is a huge potential for energy-generation in rural areas, and recommends that this prospect be given full attention.
In addition, the farmers made significant profits from the energy substitution. It costs 6,152.50 yuan (US$904) to raise a cow, which is then sold for 7,924.50 yuan (US$1,165) leaving a profit of 1,772 yuan (US$261). This represents a 50 percent annual return on investment, and net profit of between 2,500 yuan (US$367) and 3,000 yuan (US$441) per cow over eight months. If the proposal of “three cows per household” were implemented in straw-rich areas, the farmers would no longer need to migrate into cities to work. The farmer’s income while working at home would then be over 10,000 yuan (US$1,470).
Solving the energy crisis will require a multi-pronged approach. Reducing the country’s dependence on fossil fuels must include our rural residents. Chinese policies should encourage them to use the energy sources naturally available rather than force rural locations to compete with cities and industry for fossil fuels. If China pays some attention to rural energy and makes full use of biological converters such as cows, sheep and methanogenic bacteria, 700 million tonnes of straw can be converted to energy and high-quality fertilizer.
In this scenario, food production will no longer turn fields white with agricultural membrane, but dark with rich fertilizer. The government will not only be closer to its goals of reinvigorating its villages, but China also will save energy, reduce emissions and increase food production.
Jiang Gaoming is a professor at the Chinese Academy of Sciences' Institute of Botany. He is also vice secretary-general of the China Society of Biological Conservation and a board member of the China Environmental Culture Promotion Association. Jiang is known for his concepts of "urban vegetation" and allowing damaged ecosystems to recover naturally.
Photo credit: Flickr/.micki., CC License