Alexis Belonio

2008 Associate Laureate, Applied Technology
The Philippines, Born 1960

Project Goal

Turn rice husks into cheap, clean energy for cooking

Location: The Philippines

Turning Waste into Fuel

The clear, blue flame emanating from the burner of the humble, metal cooking stove is a luminous sign of hope for hundreds of millions of poor farming families. And yet inventor Alexis Belonio was initially blithely unaware that he had achieved what leading experts had declared could not be done: turn agricultural waste into purified gas for domestic cooking in a top-lit, updraft, biomass gas stove.

From Waste to Fuel

In the many countries where rice is the staple food, small changes to the use of this grain can make a profound difference. The world’s annual 650-million-tonne rice crop provides sustenance three times a day for two billion people, mainly in developing countries in the tropics. For these people, this stuff of life is indispensable, but to cook the rice they need gas or kerosene, fossil fuels that come at an increasingly unaffordable cost and with often negative consequences on health and climate.

But there is another side to rice: the huge piles of inedible husks that are often found rotting beside roads or smouldering in fields, millions of tonnes of potential energy, mostly going to waste. For Belonio, a 48-year-old associate professor of agricultural engineering in the Philippines and inventor of over 30 devices to help farmers, many of them poor, finding uses for this neglected abundance became an obsession.

Cooking with Gas
Cookers fuelled by rice husks have been used before, but they are sooty and unhealthy, and they cannot generate enough heat to cook food quickly. Belonio believed that if he could convert the rice husks to gas, it would provide a much hotter, cleaner flame to cook on. Gasification has been regularly re-invented for many purposes over the past 150 years, including for several types of stoves, but few applications have promised to benefit so many people, so simply and so cheaply.

Drawing the concept from a technical workshop on wood gasification at the Asian Institute of Technology, in Thailand, then working alone and with his own resources, he designed a simple, top-lit stove with a small fan at the base supplying an updraft of air. In Belonio’s design, a stream of oxygen converts the burning rice husk fuel to a combustible blend of hydrogen, carbon monoxide and methane gases, yielding a hot, blue flame similar to that produced by burning natural gas. At first, says Emeritus Professor Paul S. Anderson, of Illinois State University, Belonio “was unaware that what he was trying to do had been deemed . . . as not being possible. He did not even know he should have been highly surprised that he succeeded!” Belonio says simply: “It is a God-given technology. I wish to share it with people all around the world.”

Truth in Numbers
But there was a setback. Belonio’s early stoves, made in the Philippines, sold at US$100, too expensive for a poor family to afford. Further research and development conducted in Indonesia significantly reduced the retail price of the stove to only $25. This was achieved by simplifying the design of the stove in terms of operation, materials and fabrication. Thousands of cookers are now being manufactured by companies cooperating with Belonio in the Philippines, Indonesia and Cambodia. By exploiting a freely available waste product at a time of soaring energy prices, the stoves can save a family of rice farmers about $150 a year in fuel bills, a huge benefit for families that live on $2 or $3 a day.

The potential benefits are prodigious. A tonne of rice husks contains the same energy as 415 litres of petrol or 378 litres of kerosene. A few handfuls of rice husks can boil water in six to nine minutes. Best of all, the husks are usually free, either on the farm or from the waste dumps that surround rice mills. Furthermore, by being far more efficient than ordinary cookers, Belonio’s stoves reduce greenhouse gas emissions and eliminate toxic fumes inside houses. Even the char left after burning can be recycled to improve farm soils or to form bio-coal briquettes.

More Inventions
Belonio has recently scaled up the principle of his domestic stove to create a whole family of new technologies: dual-reactor and continuous-flow gasifiers for grain dryers, bakery ovens, commercial kitchen stoves, and small power-generating plants. His latest invention, a “super-gasifier”, is a powerful rice-husk stove driven by injecting superheated steam, which, he says, is ideal for cottage industries. “I was very surprised at how well it worked. That was a great moment.” His technologies are proven, reliable and inexpensive. In addition to rice husks, they can use other biomass such as coconut husk, corn cobs and sugarcane bagasse, instead of fossil fuels or timber from fast-vanishing rainforests.

Belonio’s ambition now is to spread the word about his inventions and to share the know-how, in the Philippines and around the world. He has already published a handbook on building the rice-husk gas stove, which is available for free on the World Wide Web. With funds from his Rolex Award, Belonio plans to set up a demonstration centre in Iloilo, in the Philippines, to disseminate free information and to provide training and technical advice. He will also research new inventions, such as a large-scale, rice-husk-fuelled gasifier and a gas-turbine power-generating plant for supplying electrical energy to rice mills and for lighting remote villages. He even envisions storing gas from rice husks to run farm machinery.

Professor Anderson says of this keen inventor: “Alexis’ accomplishments are founded upon his personal drive and the use of his personal resources. Establishing a centre dealing with rice husks is a worthy goal that will eventually benefit millions of people in many countries.” With tireless dedication, practical focus and technical insight, Alexis Belonio is continuing his quest to convert overlooked energy sources to ensure that families in many developing countries can prepare meals more cleanly and efficiently, at the least cost possible to the environment and to themselves.

Julian Cribb

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