Appropriate Technology Symposium



Last week I went to ECHO’s Appropriate Technology and Renewable Energy Symposium in Chiang Mai. It was a little outside my agricultural focus, but that’s why I’m here: to learn new things. We had sessions on solar power (such as the solar water heater above, located at Pun Pun farm), micro-hydroelectric generators, bio-char production, bio-gas digesters and other such small-scale innovative technologies.

We also had break-out sessions at various centers of innovation in the region. The first day we went to a farm owned by a retired chemistry professor named Kru Patum (Kru means teacher in Thai). She built this machine to turn plastic bags into fuel:

These photos come from my friend Craig, the AT guru at ECHO.

Another great field trip took us to Pun Pun, where, in addition to the solar heater above, we got to see a bio-char oven made from a 55-gallon drum. Bio-char is charcoal produced at high temperatures which is used as a soil amendment. It increases the soil’s capacity to hold nutrients, encourages beneficial soil organisms, and sequesters carbon in the process. This last benefit has drawn the attention of climate scientists, bringing further attention to the technique.

Here conference attendees load the bio-char oven with split bamboo:



The they light the top on fire. After it’s begun, the gases coming off the bamboo burn, creating anaerobic conditions in the barrel beneath, which is what you need to produce charcoal.



This set-up burns at over 850 degrees Fahrenheit, hot enough to burn off all the tar and other stuff in the bamboo, leaving nearly pure carbon with an extremely high surface area to volume ratio. It’s that surface area, created by the microscopic pores in the char, that makes it valuable as a soil amendment. It’s like installing condominiums for the beneficial bacteria and fungi in your field.

For more technical information about bio-char, check out the International Biochar Initiative.

Another big topic of the conference was cookstove design. We got to check out a number of stoves at Mae Jo University, all designed to make use of agricultural byproducts.

This stove runs on corncobs:

DSC07481This one burns rice hulls:



It’s a gasifier, which means that–like the bio-char oven–it actually burns the gases emitted by the heated rice hulls. A small dc fan forces air through the chamber, combusting the gas at the top and leaving charred rice hulls at the bottom for use as a soil amendment.

All in all it was a great chance to get exposed to different ideas in the world of appropriate technologies and be inspired about the possibilities for village-level innovation. There was a lot of creativity on offer, and many interesting people to talk to I’m grateful I got to go.

Here are all

the attendees, posing in front of Kru Patum’s farm:

There were delegates from Cambodia, Laos, Burma, China and even Sri Lanka present. A good time had by all. Thanks ECHO!



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