Biodigesters in Bangladesh

By Peter Goldmark

I'd like to invite you to take a little walk with me.

It's hot where we’re going…really hot. We're in a rural area but it's fairly densely populated…it's clear the people are very, very poor. This is low-lying country, most of the land is really not much above the rivers and the sea at all. See those levees and small mud dikes over there? See the huts clustered on those mounds? That's to try to escape the water when it floods—which is often.

We're in Bangladesh—the largest poor country in the world, or, if you prefer, the poorest large country in the world. The bay out there is the Bay of Bengal.

We walk now into the home of the Rayak family. We are here to see their biodigester.

Their what?

BiodigesterWith microfinancing for projects like biodigesters (above), farmers in Bangladesh are helping reduce global warming and avoiding illness. Credit: David Yarnold.

This is a cement vat that holds their animal waste. Actually that odor you're smelling is unmistakable, so you know darn well what it holds. In this case, it's not cow dung, it's poultry waste…chickenshit, to use the vernacular.

It's a three- cubic-meter tank. (This is a relatively large, souped-up biodigester model, so to speak, like a car with an overhead cam or turbocharged engine.) The waste runs from under the laying area of the chickens through a banked cement funnel into the biodigester, where it…ferments. I believe that's the word the connoisseurs use. It ferments anaerobically, and presto! It produces…methane. A fair amount of it. This is trapped under pressure beneath the lid of the biodigester, and it is piped, in a simple plastic line hung from the trees, right into the Rayaks' home. The methane is used for cooking and lighting. It's essentially natural gas–clean, odorless.

The Rayak family is moderately prosperous by Bangladesh standards, although you would find them very poor. I saw at least six children, there may be more. They have a serious chicken farm. And now that they have clean energy, they're no longer chopping down trees and shrubs for fuel, their children don't have respiratory disease, and people emitting carbon in far away places like you and me are helping them to buy the biodigester – by buying the credits for avoided carbon generated by the Rayaks, aggregated by our partner Grameen Shakti, bought and underwritten through our partner E&Co and marketed to corporate buyers by one of our other partners, Ecosecurities. (And Grameen Bank is making a micro-loan to the Rayaks to help them finance the purchase of the biodigester.) It's really quite a virtuous cycle, if you break it down and look at it closely.

Here is a family that either used expensive, carbon-emitting kerosene, or burned wood from shrubs and trees that also emitted carbon, and — worse — filled the house with smoke and particulates, putting the children at serious risk of ARI. Now they have clean, affordable energy – that emits a fraction of the carbon that was emitted before. So let’s add this up:

  • healthier children
  • less deforestation
  • less carbon emitted
  • cheaper energy for the family
  • the residue is a very powerful fertilizer, which the family can use or sell
  • and indirect benefits: higher literacy, lower fertility

Now maybe you begin to understand why EDF is working in this village with Grameen, helping monetize the avoided carbon to make the biodigesters cheaper and more acceptable – and using carbon financing to help Grameen take the whole system to scale.

But wait. Look overhead. Right there, on the tree branch over the biodigester — do you see the plastic lines? I see 14 lines spreading out through the trees overhead…What is going on, Mr. Rayak, I ask? It turns out that Mr. Rayak – who as you may recall had a deluxe, V8 turbocharged jumbo-sized biodigester, is selling methane to 14 other families. He has become, in fact, a clean energy entrepreneur. No one has anticipated this.

When I have dinner with my old friend Mohammed Yunus, the founder and head of Grameen next evening, he smiles knowingly and instructs me that this is not at all surprising…that of course, we were trying all along to tap into the initiative of the poor, that they are good credit risks (he slips into his basic Grameen shtick). I think he is full of…well you know, what we were talking about it earlier, and politely I tell him so. "Come on, Yunus, neither of us saw this coming." He beams, and we both laugh. We both like this unanticipated dividend to our project.

Does all of this seem far away? Not much to do with cap-and-trade? Hard to fit the Rayak family and you and I into the same frame?

But that's the whole point, isn't it? The Rayaks and you and I are all in the same boat. That is the crux, the brutal reality of the enormous adventure on which we have embarked: a race to see if we can get enough carbon out of the human economic enterprise to allow the atmosphere to stabilize before the most catastrophic consequences of global warming occur.

Seeing all of these pieces — the huge oil majors; Gazprom; the automobile industry; the assembly-line of Chinese coal plants; buildings around the world that leak huge amounts of energy; the vast deforestation underway in Indonesia protected in some places by the army; and the Rayak family, and his 14 neighbors who are buying methane from him — seeing all of this in the same frame – that's what's required, isn't it?

We are trying to convince, coax and cajole six billion people to get on the same road and face together in the same direction: to choose the road of low-carbon, high efficiency, economic growth and individual opportunity.

If you tell me that this is difficult, I will nod in grim agreement.

If you tell me that it is idealistic, I will tell you that it is essential.

If you tell me that it is romantic, I will tell you that no door ever opens unless you knock.

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2 Responses

Comment from Senor Pescado
October 13th, 2010 at 10:43 pm

very nice, we can do same in El Salvador, I have design for small one with toilet over tank

Comment from Tom Parrett
October 15th, 2010 at 12:02 pm

Great story. Another about this country has me concerned: that Bangladeshis in the delta understand flooding and fierce cyclones and they've learned over generations good ways to cope. But now, faced with rising sea levels and more intense storms, the country's leaders are welcoming guidance from the U.S. Corps of Engineers. The Corps specializes in "hard" solutions — concrete and steel dykes and piers and bulkhead-lined channels, which are likely to be exactly the wrong approach for Bangladesh's flood-prone delta.

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