Wednesday, June 16, 2010

Michael Yon: Gobar Gas II

I love articles like this. It shows us how people are solving a survival problem, but aren't thinking about it as a survival problem. To them it is just the answer.

A Gurkha veteran named Lalit whom I met, deep in the jungles of Borneo, at a British Army man-tracking school, came with good ideas.  Lalit began a conversation by announcing that many of Afghanistan's energy, land restoration and fuel needs could be solved if the Afghans would immediately adopt "Gobar Gas" production. This mysterious substance could improve the lives of Afghans as it had that of the Nepalese, he said, as, with great enthusiasm, he began to explain.
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“Gobar” is the Nepali word for cow dung.  The “Gas” refers to biogas derived from the natural decay of dung and other waste products and biomass.  In Nepal, villagers use buffalo, cow, human, and other waste products for biogas production.  Pig and chicken dung are used in some places, as are raw kitchen wastes, including rotted vegetation.
Gobar is typically mixed with a roughly equal amount of water, and gravity-fed through a pipe into an airtight underground “digester,” where naturally occurring bacteria feast on the mixture. This anaerobic process produces small but precious amounts of gas. That gas can be fed directly into a heat source, such as a cooking stove, and used to power it.
The biogas that is produced is 50-70% methane by volume, similar to natural gas, and a convenient source of clean energy. The biogas is easily collected and stored for lighting, cooking and other household uses.  After the bacteria have finished digesting the dung, the byproduct is a rich organic fertilizer (sometimes called slurry).  That fertilizer is more effective than raw dung, with two important benefits for hands-on farmers:  it doesn’t smell bad, and almost all the pathogens and weed seeds have been destroyed.  There is no downside.  No waste.  No poisonous residues or batteries.  No moving parts.  Gobar Gas is an astonishingly elegant tap into “the circle of life” that environmentalists, economists, development people and humanitarians should all appreciate.
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Before coming to the biogas sector, Mr. Rai worked in photovoltaic energy.  “Biogas has much greater socio-economic benefits,” said Mr. Rai in his Kathmandu office, “but biogas is not sexy like photovoltaic, which mostly helps men.  Biogas mostly helps women—the men don’t really notice because they still get cooked food, so why would a man invest 25,000 rupees?  But men will invest in photovoltaic because they get the sexy solar panel,” he said.  “Even women sometimes will opt for photovoltaic solar power because they don’t realize the headaches, coughing and eye problems come from cooking.”
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Ten kilos of dung yields roughly an hour of stove burning time, and one of those skinny cows produces about 12 kilos per day.  KQ had a great herd of sheep—probably a couple hundred—kept in pens when not out feeding.  Villagers scrape sheep dung from the pens, which they mixed with cow (I saw only one), mule and horse manure for cooking.  A small stream runs through the village.  Afghans will use greenhouses if taught; I’ve seen them in Helmand and Oruzgan.


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The bio-slurry from the digester is so effective for growing crops that in some countries, according to Mr. Rai, biogas is not an energy program but an agricultural initiative. In Vietnam it has been adopted for sanitation.  The biogas and the great sanitation benefits, including reduction of waste-borne diseases, are byproducts in one place and impetus in another.  In Karbasha Qalat, with a few greenhouses using the bio-slurry, the standard of life could dramatically improve.  There must be thousands of “Karbasha Qalats” in Afghanistan.
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For a typical Nepalese family, installing a biogas facility, even with subsidies, is expensive.  But people feel that the investment pays for itself quickly.  Some women reported that Gobar Gas installations completely returned the investment within a year to 18 months.  SNV figures are more conservative, but even they show a complete return on investment after about three years.
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But it’s important to consider the less easily monetized but still very real benefits of using Gobar Gas.  Saving 2,500 kilograms of trees each year per family has long-term economic value to farmers as the soil is revived. Improved health from better sanitation and the absence of constant wood smoke in the home has clear economic benefits, as does the ability to send children, freed from the labor of searching for fuel, to school.  These gains and many others don’t fit on a balance sheet.  But they are the conditions for real, long-term economic and social development in the Third World. 
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Households of four to five people require about two cows or buffalos to create enough raw materials.  A thousand chickens or a hundred small humans can match one big water buffalo, and four pigs equal about two cows in dung production. Connecting the family outhouse gives a slight Gobar boost, but is more useful for sanitation than fuel.
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Afghanistan recently won the silver medal in a competition for the world’s most corrupt nation.  Somalia beat them by a nose, walking away with the gold medal, and all the gold that was meant for the people.  Adding resources to Afghanistan has only made it more corrupt by giving thieves something to steal and more power after they steal it.  Grassroots efforts can bypass many of these issues.
More than forty of the world’s most developed nations are nurturing Afghanistan, trying to push, pull and prod it into shape.  Simultaneously, it won a silver medal for corruption.  This means, at very least, that top-down solutions are typically not working.  The government cannot be trusted with development money, because they don’t care about the development part.  We might as well feed the money into bio-digesters.  Fundamental progress in Afghanistan can best be achieved with more bottom up efforts.  That’s what worked in Nepal. 
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The caloric rollercoaster for the star anaerobes begins at about 15ºC (59ºF).  That’s when they start waking up and going to work.  To kick them out of bed, some farmers pile straw atop the digester.  Decaying straw produces heat.  Busy anaerobes begin to help by producing heat inside the digester.  Some people build greenhouses over top, or barns.  In China, according to Jan Lam, the SNV biogas project manager in Cambodia, “The ‘3 in 1’ approach is popular.  A greenhouse contains a vegetable garden, pig sty and biodigester.  Vegetable waste is fed into the pigs and their waste goes directly into the plant which is often large enough for cooking and a water heater.”
In cold weather, digestion can be prodded with warm water.  As temperature rises, production rises, but the top of the “thermo coaster,” the ideal temperature, is about 35ºC (95ºF).  Good dung, plenty of water, little oxygen, and the anaerobes do their job.  Above that temperature, they slow down, trying to shed some heat.  But if slowing down doesn’t work, if their world gets too hot, they die.
Installing a digester is like adopting a baby elephant.  It can’t get too hot or cold.  It must eat every day, and drink lots of water.  Sometimes it needs a little washing.  If the water source is far, the system is impractical.  Many parts of Nepal and Afghanistan are impractical for baby elephants and biogas. 
So we have here a simple and durable system for creating cooking fuel, that also handles major sanitation issues and creates great fertilizer as a byproduct.

Unless you are running a diary farm you aren't going to have enough input to make heating fuel, but cooking fuel is a great first step. But a well designed and well sited house will not need very much heating or cooling.