The Big Necessity (18 page)

Biogas can be produced from the fermentation of any organic material, from wood to vegetables to human excreta. In an oxygen-free digester, which acts somewhat like a human stomach, microorganisms break down the material into sugar and acids, which then become gas. Mostly methane, with carbon dioxide and a little hydrogen sulfide, biogas can be used as fuel for cooking hobs, lights, and, sometimes, showers. It can also be converted into electricity. The slurry that remains from the digestion process is good fertilizer, and considerably safer than raw excrement.

At last count, if official figures are reliable, 15.4 million rural households in China are connecting their toilets to a biogas digester, switching on their stoves a few hours later, and cooking with the proceeds. Worldwide, Nepal has more digesters per capita than China. India,
meanwhile, has installed several million, though they run on cow dung, and there are only so many cows. China has a billion humans, and that means a billion suppliers of a cheap and inexhaustible supply of clean energy.

The scientific epicenter of China's biogas program is the Institute of Biogas, or BIOMA, a complex near the American consulate in the city of Chengdu, in China's Sichuan Province. The city is known for its panda research institute, one of whose residents is a sponsored panda called Microsoft, and is situated on a plain known as
Tianfuzhi guo
, usually translated as “The Land of Abundance.” The lands around Chengdu are China's breadbasket. Here, farmers can get rich by the power of the soil. The capital of the farming lands is a spacious, pleasant city that contrasts with the smoggy, sweltering soup of Chongqing, a grim city of 10 million people which I had flown into.

Mr. Fang, a neat and pleasant man, is the deputy director of China's biogas program, though he's only been in the post for two months. Before biogas, he worked on agricultural mechanics at a rice research institute. He knows more about tractors than digesters. Perhaps for backup, he has gathered a welcoming committee of half a dozen scientists, including a fierce woman who is clearly there on Party business. Mr. Fang has prepared a PowerPoint introduction to his institute's work. Onscreen, China's biogas program is going full steam ahead. Between 2001 and 2004, Guangxi Province installed 250,000 digesters per year in rural households, the most of any province. Biogas is most popular in the southern provinces of China, where the climate is warmer (biogas digesters work better in temperatures above 50 degrees F). To combat northern temperatures, though, two digester systems have been developed. The pig-toilet-vegetable system links a pigsty and toilet to the fields, whereas the four-in-one model adds the element of a greenhouse, under which the digester is installed. The four-in-one was developed in Liaoning Province, where winter temperatures reach–22 degrees F, and where a digester without a greenhouse to shelter it would only work for five months a year.

The Institute of Biogas was set up in 1981 with support from the United Nations Development Programme (UNDP). The building dates
from then, and from a tour of the laboratories below—which house dull jars of brown test material in spartan labs and rickety-looking equipment—it shows its age. Nonetheless, according to Mr. Fang, BIOMA is the only such research center in China and famous internationally. The institute has already assisted Romania, Guinea-Bissau, and Rwanda in setting up biogas projects. (I forget to ask whether it was involved in Rwanda's extraordinary biogas project, whereby half of the country's prisons generate gas and electricity from the excreta of genocidal murderers.)

The BIOMA building, says Mr. Fang with some pride, also houses the editorial headquarters of
China Biogas
journal, and has completed more than two hundred research projects for the Chinese government. I should not be fooled by the age of the equipment (though Mr. Fang also asks me to put in a good word with UNDP about more funding). Serious work is done here. Professor Zhang, one of the scientists present, is working on “increasing gas yield by improving officially sanctioned pig diet.” Dr. Hu is interested in microbiology and the fermentation process. Elsewhere, some of the institute's staff of eighty-seven are attempting to reduce the risk of bird flu transmission. (This is a real risk, since digesters require the close proximity of animal and human.)

Despite the complexity of the research, the scientists insist that the system is simple. “The farmer doesn't have to do anything,” says Dr. Hu. There is no stirring, no caretaking. “All he has to do is ensure there's input and use the output.” To translate: all he has to do is use the toilet, and then the gas. If I want further proof, they suggest I go to see it in action, in the nearby village of Mian Zhu.

 

If towns with six-lane highways running through them are villages, then Mian Zhu is a village. We are directed to stop by the side of the road and wait for an escort, which is revealed to be two officials from the Rural Energy Office. I stupidly never took their names, so I will refer to them as White Shirt and Red Shirt, with apologies for disrespect. They take us through a field by the roadside to a compound of
three houses, each with huge wooden gates on which colorful warriors and symbols have been painted. On the other side of the warriors, a trail of blood leads to—or from—the pigsty. Mrs. Tien, whose house this is, says they've just killed a pig. They're now a six-pig family when ten minutes ago they were seven. She is smiling and excited. “She's saying, ‘They've come to see our biogas digester!'” says Red, though of course there is nothing to see but a concrete circle in the ground. Digesters have to be sealed to work.

In Mrs. Tien's kitchen, I am given what will be the first of many biogas demonstrations. They generally proceed like this: switch on the biogas. Sniff. Express pleasure that it smells only faintly sulphuric. Light the gas. Express more pleasure. Switch on the light. Take a picture (which never comes out well because the light isn't that strong). Mrs. Tien seems genuinely excited to demonstrate her free gas, though I get the sense she's done it before. Red Shirt says that Mian Zhu is the centerpiece of the Ecological Homeland program, and 60 percent of houses in this area have digesters, making a total of 10,000 households. People like biogas, says White Shirt, and anyway it has an illustrious history. “In 1957 Chairman Mao went to Hubei province and saw a biogas digester and said, ‘This must be well-promoted.'” And it was so.

Sitting on an expensive sofa next to a huge TV screen in Mrs. Tien's living room, I ask the officials if biogas has any disadvantages. They say there are none. Any problems can be dealt with by the technicians of the Biogas Management Unit, whose telephone number, since I ask, is 65980212. “Each town has one to three teams of workmen, so they usually come within a day.” By 2010, they expect everyone in this province to have installed a digester. If there are malfunctions, the network of rural energy technicians can fix them swiftly. It all sounds too good to be true. But, as an Indian biogas expert tells me, China can do this, because China can impose from on high. “India is a democracy,” the expert says. “We have to ask, to plead, to persuade. It takes longer. It is harder. China can do things faster.” Also, China can pay. Households that buy a digester get a 1,200 yuan ($175) grant toward the total cost (usually about 3,000 yuan). It all
sounds perfect. Even so, I am not persuaded by the Potemkin village of Mian Zhu.

 

To reach the regional headquarters of the Chinese Women's Federation, which are located in the pleasant city of Xi'an, one must first walk the length of a street of shops and barbers. The barber shops have barbering equipment and the added odd extra of overly made-up women smiling insistently at my companion, a Caucasian man. At his approach, doors open and garish faces pop out before they see me and the smile disappears. After that gauntlet, I arrive at the Women's Federation in a sour mood, but it doesn't last, because my appointment is with Wang Ming Ying, founder and president of the Shaanxi Mothers' Environmental Protection Volunteer Association. Wang's energy can soothe the foulest tempers, even mine.

Her office is not much bigger than a cubicle, with a bed for the times she regularly works too late to get home. Wang is also small, but her spirit is disproportionate to her stature. She radiates warmth, even in translation, and she will not hear of starting a conversation without first providing platefuls of huge peaches and gigantic watermelons. “You have to eat melons to help the farmers,” she says. “This year there are too many melons. Eat! Eat!”

I'd read about the Shaanxi Mothers a few months earlier, when they received a sizable international prize from a sustainable energy foundation. The group won for installing biogas digesters using human excrement in provincial areas of Shaanxi, where rural life is generally hard and the winters cold, and where any extra energy source makes sense.

In theory, biogas has all sorts of advantages and no disadvantages. It saves on artificial fertilizer use because the slurry is filled with nutrients. Scientists from China's Research Institute of Medical Military Scientists decided biogas slurry increased vegetable yields by 50 to 60 percent. One person's urine and feces can fertilize 885 square feet of land, according to another calculation. Because biogas can be used for cooking and lighting, it saves on conventional energy consumption of
liquid petroleum gas (LPG) or coal (one cubic meter of biogas is the equivalent of six hours' worth of a 60–100 watt bulb). It saves forests, because wood is the commonest fuel source in rural China. A 1991 survey found that a five-person family in Guangxi used 2.3 tons of wood for fuel per year. And it saves on labor: on average, a rural Chinese woman preparing food on an iron stove fed with rice stalks or wood takes two hours to cook a meal. A meal cooked using biogas can be ready in twenty minutes. Fast food.

Biogas has a long history, though the length of the history and its exact birthplace are debated. The Babylonians are credited with noticing that gas coming from sewage could be useful, as are the Assyrians. Marco Polo reportedly saw covered tanks of sewage—simple anaerobic digesters—in China. And Count Alessandro Volta, as well as inventing the electric battery and giving his name to voltage, concluded in 1776 that there was a correlation between decaying organic substances and the amount of gas they gave off.

The Chinese say that they have been using biogas for as long as they've been spreading
fen
on their fields. In biogas circles, the credit for pioneering the first noteworthy biogas digester is given to a leper colony in Bombay, which set up a digester using
gobar
(cow manure) in 1859 and gave Indian lepers the new concept of
gobargas
.

A discussion at the Institute of Biogas had produced the consensus that Chinese biogas owes its existence to a man called Luo Guo Ri, who developed a biogas digester in the 1930s and installed it in several locations around Shanghai. But both Luo Guo Ri and his plans were swallowed up by the Japanese when Japan invaded China in 1937. The plants were destroyed and that, for several decades, was that. In 1972, though, an oil crisis caused certain careful scientists to revisit Luo's work. China had energy needs but, in the words of Mr. Fang, “Our door was closed. We could not ask for support from outside. We had to find other energy sources.” If oil was expensive, then why not tap a resource produced, for free, by—according to population figures back then—850 million bowels? It made political, economic, and agricultural sense. A campaign was launched with the slogan “Biogas for every household.” For the next five years, up to two million digesters were installed each
year, in rural households that had toilets and enough pigs. To function efficiently and productively, animal manure is required to boost the volume of excreta. A cow's dung can produce 500 liters of gas a year, while a human only produces 30. There aren't many cows in China, but there are pigs. China's energy problems would be alleviated by a partnership between pigs and humans.

Except it didn't work. By 1980, half of the shiny new digesters were broken. The problem was humans, technology, and the fraught relationship between them. These early digesters were made of brick and often leaked. Also, the Chinese academic J. X. Hong, writing in
China Biogas
in 1993, estimated that a digester needs 66 pounds of feces daily to function properly, along with 13 gallons of urine and water. This works out to the produce of twelve people, an unlikely family size in a country where couples were permitted one child only. Farmers with fewer pigs added rice stalks to boost the digestion volume, and the stalks caused clogging.

There was little training in maintenance and no network of repair centers to step into the knowledge breach. When the units broke, they stayed broken. So the biogas digesters, despite their potential benefits, were abandoned, and China's farmers went back to their smelly
mao kun
—a hole-in-the-ground latrine—and to spreading the hole's contents on the fields, crude and teeming with pathogens.

Once again, farmers' wives set off each day to cut wood from the forests. Deforestation reached a scale that alarmed even the far-off government in Beijing. Thoughts turned to the broken digesters, and to how they could be improved. At the same time, other thoughts were occupied by the phosphorus question. Human excrement contains nitrogen and phosphorus, which is plant food. Plant food is worth money. This economic fact oiled the wheels of the night-soil collection industry enough to make its operators powerful. By the late nineteenth century, the leaders of the night-soil trade had been given the ironic title of
fenfa
, or shit lords. The nickname was derived from
junfa
(warlords) and neither were to be messed with. In 1925, when Beijing police told the
fenfa
to move their drying yards—where their product was aired, producing awful odors—they only had to go
on strike for three days before public disapproval forced the police to back down.