Tinkerer: Inventor Alexis Belonio created a series of gas stoves that run off rice husks. (Courtesy of Kirsten Holst/Rolex Awards)
Rice-powered stove ignites new hope for poor farmers
Once thought to be waste, rice husks now can be used as clean, cheap fuel for developing countries.
By Gisela Angela Telis | Contributor for The Christian Science Montior/ December 3, 2008 edition
Alexis Belonio’s obsession with rice husks began in 2003, when rising fuel prices and heavy dependence on foreign oil slammed his native Philippines with an energy crunch.
“I saw rice mills throw husks into the rivers,” says the agricultural engineer. “I started thinking about using them as fuel.”
Mr. Belonio was already an accomplished inventor, having designed over 30 devices ranging from paddy dryers to water pumps for poor Filipino farmers. So his thinking led him to the cooking stove, an item fraught with expense and danger in the developing world.
More than a third of the world’s population can’t afford propane or other petroleum-based cooking fuels, relying instead on biomass such as wood or charcoal. Most biomass is burned in inefficient stoves that emit soot, smoke, and toxic fumes.
Belonio envisioned a safer, cleaner, and less-expensive way to cook. Working largely in isolation and with little funding, he turned rice husks – an inedible byproduct of milling rice for food – into a bright blue flame.
Inventing the impossible
Turning rice husks into fuel isn’t a new idea: Several cooking stoves invented for the developing world, such as the Lo Trau (Vietnamese for “rice husk stove”), can use the agricultural waste. But husks are messy. They tend to make a smoky, unstable fire and leave a tar-like residue, says Kirk R. Smith, an environmental health scientist at the University of California, Berkeley, who specializes in indoor air quality and frequently tests cooking stoves.
Burning husks cleanly enough to rival a propane or butane stove at low cost was deemed impossible by many stove developers.
“We were sure this couldn’t be done,” says Paul Anderson, a geographer who has spent the past five years since retiring from Illinois State University designing stoves for the developing world.
Mr. Anderson worked on his designs with Tom Reed, a former Massachusetts Institute of Technology chemist. Mr. Reed invented the top-lit updraft (T-LUD) biomass stove, one of a class of stoves that can “gasify” its fuel. In gasifier stoves, biomass burns until only charcoal and burnable gases remain; the gases are separated and ignited, producing a smokeless blue flame like that of a natural gas stove, leaving only charcoal behind.
In traditional wood fires, these two processes happen together, creating the familiar yellow, smoky flames. Separating the stages makes for a cleaner, more controlled burn that has made the technology popular worldwide.
Reed and Anderson burned wood in their T-LUD stoves, but neither succeeded in gasifying finer agricultural waste. Then, after seeing a Reed T-LUD stove demonstration at a conference in Thailand, Belonio started imagining a husk gasifier.
“Nobody told Alexis Belonio you weren’t supposed to do this with rice husks,” says Anderson. “So he just went off and did it.”
The secret to Belonio’s success is good engineering and adequate air, Anderson explains. His design includes a small electric or battery-powered fan that circulates air through the husks, enabling them to burn more efficiently.
The fan and fuel sit in the bottom of an iron and steel tube more than a yard long. The tube traps the gases the husks release when they’re lit – mostly hydrogen, methane, and carbon monoxide – and combusts them at the burner on top of the tube. Users can raise or lower the flame by changing the fan speed. When the husks have burned, the remaining charcoal can serve as a fertilizer for crops.
“This technology is superior to virtually everything else out there,” says Anderson. “Belonio stimulated me and others to go back and look again at rice husks and other fine materials.”
Belonio’s stove does have its drawbacks: It requires access to batteries or the electrical grid, and its $20 price tag is too steep for the poorest potential users.
“[The cooker] isn’t exciting until it’s affecting the lives of many people and you can prove that,” says Mr. Smith, noting that Belonio’s stove has not yet seen widespread testing in the field.
Abundant resources
To millions of people in the world’s rice-rich regions, the stove could offer a cleaner, cheaper cooking option that recycles an existing waste with little impact on the environment.
“In Myanmar, I recently visited a mid-size rice mill that was using rice husks to power the mill, produce electricity for the house, and do the cooking on four larger stoves,” says Martin Gummert, a specialist for the International Rice Research Institute. “There were still husks left.”
Mr. Gummert estimates that the world’s 645 million-ton rice harvest in 2007 generated 129 million tons of rice husks. This leaves an abundance of fuel for Belonio’s stoves, which can wring about 20 minutes of cooking time from one pound of husks.
Because rice husks are cheap and widely available, running the Belonio stove costs only 20 cents a day in the Philippines – most of which is the cost of running the fan. That can save farmers more than $150 a year on fuel compared with regular stoves.
The stove’s promise hasn’t gone unnoticed. Last month, watchmaker Rolex named Belonio as one of its 10 exemplary innovators. Belonio says he plans to use the $50,000 prize to build a stove demonstration and research center in Iloilo, Philippines. He’s also working with an Indonesian company to manufacture 30,000 units for distribution – and that, adds Smith, will be the technology’s ultimate test.
“If people end up using it day in and day out,” he says, “then Belonio’s got it.”
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Comments
3. carbajal | 12.04.08
good luck! Mr Belonio i would love to have your stove. how big well it be? since i live in California and we may have an earthquake that stove would be very useful. i will keep reading to see how it works out!! i would place an order!!–please keep us posted on how this stove is doing!!
4. manfredostrowski | 12.04.08
To me this is a really enchanting story, and I hope to hear more about
it soon! Many thanks!
5. Roy Mattox | 12.04.08
Congratulations for your tenacity! What if you were able to use a small solar panel to run the little fan motor,then they wouldn’t need to keep purchasing batteries. Someone has to be making a cheaper solar panel by now.
6. Joseph Hiddink | 12.04.08
The US making a stove like this? You need business brains for that. China will probably do it and at a lower price than the USA it ever could do.
7. Shirley Freeman | 12.05.08
Congratulations on this great innovation. Some say that inventing a cheaper battery (for cars, this stove, and perhaps many other uses in technologically sophisticated as well as areas with little technology) would greatly improve our chances of ‘going green’.
8. Doulas Raybeck | 12.05.08
It’s impressive what can be done when you don’t know that it “can’t be done.” There are hundreds of examples of technological and social innovation and we need to expand their visibility.
9. Nus Azam | 12.05.08
How about a thermopile (thermocouples wired together) to generate a low-voltage supply for powering the fan?
10. Yon Carpenter | 12.05.08
…the picture of the stove and it’s description leads me to believe this stove is a knock off of a battery fan driven wood burning backpacking stove I have been using for since 1995, the Zip Stove.
I have two, one an ultralight titanium model. I can cook, have a nice contained fire and light my campsite without having to pack a canle lantern
even.
They rocket and roll, check it out for yourself at http://www.zzstove.com
BTW, I am not associated w/ the firm, just love the concept and their product!
11. George France | 12.06.08
Coming from the Philippine countryside and a fellow engineer of Mr. Belonio, I do hope that we can magnify this concept into a big power plant that surely is sustainable. With that the Philippines would become not only the world’s top rice consumer but world’s top user of rice power as well.
12. Alexis | 12.06.08
To all who are interested in the rice husk gas stove technology, kindly download the handbook by plugging in to http://www.google.com or any search engine Rice Husk Gas Stove Handbook. The technical drawing can be found at the appendix of the book. The improved version of the stove will be available next year. Send email to atbelonio@yahoo.com if you need further information. Good day and God bless!
13. Happy | 12.06.08
Dear Sparkes,
I think rice husk availability worldwide is just a fraction of the total energy need. There are rice husk power generating plants being installed worldwide which can replace more oil than the stove can. Basically, I think this stove is just a missionary technology that can help the grassroots in the developing world.
14. Al Cherri | 12.06.08
This is good technology and Mr. Belonio is helping to improve our environment. I would like to suggest that one possible means for doing away with the need for an external electric power supply would be the introduction of a “Thermopile” into the system. A Thermopile could supply all the electricity needed to run the fan.
15. Chris Dewhirst | 12.07.08
Just a low tech thought for people that may not be able to find or afford batteries for the fan- I haven’t seen the stove but could a steel spring similar to the old clock springs in wind up alarm clocks be geared todrive a fan for twenty minutes; changing the resistance could allow the fan to move faster and ratcheting it down would slow the speed. A minute of winding would potentially give twenty or thirty minutes of power to the stove; good luck to the inventor.
16. Alexis | 12.07.08
Hi Al and Nuz!
I agree with your idea of using the thermocouple wire. I am presently doing research on it in my other small stove project like wood charcoal gas stove. The power input is much less as compared with the rice husk gas stove which is 16 watt. I think China is producing this thermo-electric device that can be attached to the stove to run the fan. Other mechanical device which is suggested by Chris can be another option. I will try to do it once I have the opportunity to build it.
Try to visit the website below re my gasifier projects:
17. Rita | 12.07.08
Suggest taking a look at the FreePlay windup radio, originally developed for Africa. A few minutes of winding can run the radio for about half an hour, so perhaps it could be adapted to power the stove’s fan.
Alternatively, maybe use bicycle pedal-power directly, by substituting the fan assembly for the bike’s rear wheel. If it’s a quick change-out between wheel and fan (like a single-speed bike), the cost could be kept down for those who already have a bicycle for transportation.
18. Jason Rosette | 12.08.08
Yea, I agree with above–first thing I thought of was the Zip Stove (camping stove) on of which I’ve had for 6 or 7 years already. Fan blower in bottom, burns sticks, pinecones, whatever you find that can burn.
Shouldn’t Zip Stove get some credit?
Also just a fan of Zip stove, no obligation to endorse, etc. But, give credit where credit is due…
19. steve | 12.09.08
It would be better if it did not require an electric fan. So the poor are supposed to spend lots of money on batteries now? Thermoelectrics are not the solution either - not for the poor anyway - they are expensive. Thermoelectrics also require some more engineering as you have to dissipate the heat. Get the thermoelectics too hot and they will be destroyed. That’s why many thermoelectic demonstrations show them being heated for just a short period of time. There are some high-temp thermoelectrics but they are very expensive if you can even get them (generate power on space probes etc). I applaud the effort however- just don’t think it will work in the long-run however.
20. Steven Schrock | 12.12.08
There is an existing process for running the fan without a battery. I suppose the crank generators that are popular in flashlights might be inadequate, however there are little steam powered generators using solar heat focused with a parabolic mirror that could do the job. You can see demonstrations of these on U Tube.
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4. Rolex Recognizes Social Entrepreneur w/ Rice Husk Powr’d Cooker « Campus Entrepreneurship | 12.18.08
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1. Sparkes | 12.04.08
How long will it be before the American oil companies find a way to stop manufacuring this stove. It might just affect their bottom line billion dollars profits and we know they will do anything worldwide to maintain their control of the world’s energy.