Great Environmental-Friendly Stove Innovation Whose Waste Earns The Cook Extra Money

Rarely has the need for new ways of thinking been more glaring than in the world we live in today. We are in desperate need of paradigm shift especially through a fundamental transformation of our social and economic mindsets because we actually need creative and innovative solutions that will foster sustainable growth, secure jobs and increase our competitive abilities.

As economies around the world are re-orientating towards low-carbon, green growth paths and accelerating innovation and technology transfer, this year’s Kenya Climate Innovation Center (KCIC) Forum at The Strathmore Business School Auditorium witnessed Thika’s own Francis Mugecha Ndung’u in a forum considered as the world’s biggest clean technology platform for entrepreneurs, investors, innovators, donors and corporations.

With technology, its deployment and diffusion being acknowledged as a key factor in efforts to mitigate and adapt to the current and future impacts of climate change, Francis’ presentation actually gave him a very rare and unique opportunity to brush shoulders with great minds in climate technology entrepreneurship such as Mr. Ganesh Rasagam, World Bank’s Practice Manager for Innovation and Entrepreneurship, Trade & Competitiveness.

Francis is the C.E.O. of Chaff Energy, a social enterprise for clean-tech which normally manufacture gasifiers and pellets from rice husks. These gasifiers use locally available waste from rice to produce high grade heat equivalent to the liquefied petroleum gas (LPG) gas stoves.

Francis’ project at the exhibition was a super low-cost, blue-flame rice husk gas stove that was targeted to provide households, especially within the rice growing areas of Mwea and Ahero, with an affordable clean-burning cooking device that used rice husks as fuel.

Its goal is to reduce carbon gas emissions and poverty through more effective use of these rice residues which generally are thrown away as waste. Emissions such as volatile organic compounds from these stoves are generally very low in comparison to other forms of combustion heating.

“The country produces about 30,000 tonnes of rice husks annually which, at the moment is wasted. This has been a big problem in terms of waste management,” says Francis.

In the Kenyan rural context, households still rely on traditional solid fuels for daily cooking, using rudimentary devices like three-stone fires which result in a very low-efficiency usage of the fuel. It also has huge health impacts for women and children who are exposed to harmful smokes and burn risks, besides increasing the stress on a delicate environment threatened by uncontrolled tree cutting.

On the other hand, with fuel and energy prices all over the globe shooting up, paraffin and LPG are quite expensive. The use of wood for fuel in the rural areas causes forest denudation at an alarming rate as harmful gases released to the atmosphere. This become a matter of concern to Francis who was brought up in a rural set-up and bore first-hand experience of the challenges these people go through on a daily basis.

He therefore thought of coming up with a low-cost stove that used locally available raw materials such as rice husks which were plenty in rice growing regions but worked just like an LPG cooker. He thought of a stove that could prevent field burning of rice husks and still be used as a substitute fuel for rural households as a means to replace firewood and charcoal use. This way, he could be of help to even the poor families in the rural areas.

“We are in the process of manufacturing gasifiers that will use locally available waste such as the rice husks to produce high grade heat equivalent to LPG and fuel. Once this stove starts to gasify, it produces high quality gas that is blue in colour. There is generally no pollution or emissions,” he said.

Basically, this stove works like a normal cooking range but is powered by burning rice husks. It is comprised of a burner, a gasifier reactor, a char chamber, a fan and a control switch. The idea is to limit the amount of air when burning the hulls. This process allows the cooker to produce a luminous blue flame, similar to LPG-powered stoves.

The stove is not only environment-friendly, it is also cost-efficient for a kilo of rice husks lasts for about an hour and in areas like Mwea and Ahero, it can be acquired for free. The electric consumption of the fan is negligible. This means cooking using the stove will cost six times less per hour, than while using an LPG cooker.

“The stove produces very hot blue flame, about 560 degrees hot. You can actually boil 5 litres of water in less than 5 minutes. We use a 12-volts DC fan that consumes very little power. We use it to propel air inside the gasifier.”

Rice husk pellets are highly densified and compacted into small size which make their storage and transportation much easier and convenient. Rice husk pellets can burn longer and the combustion rate of rice husk pellets can be above 95%.

According to Francis, the by-product emanating after burning the husks or pellets is very useful as it is a source of money too.

The carbonised waste one gets from the burnt husks is very ideal for soil fertility. It is inert, meaning it doesn’t interact with other compounds in the water and soil. Francis says that is very indigestible to soil microbes and basically doesn’t break down in the soil. He adds that it persists in the soil for a long time, continuing to add its benefits, and doesn’t change over time.

“This carbonised waste that you get after your cooking is complete can be used in the farm as biochar whose effect on the farm is far much better than both fertiliser and manure. If you use biochar in your soil, you do not have to keep replenishing it every time you want to re-plant. You can re-plant new crops for like three years without adding more biochar or manure and the results will still be much better than the one for manure,” he explained.

As for the pellets, the waste is in form of charcoal granules which can be used in an improved cook stove. They can be sold to other consumers at a price six times higher than that of the pellets themselves.

“Basically, what I am trying to imply is that you make money by just cooking. Every time that you use our gasifiers, you make about a kilogramme of the granule which translates to about a hundred shillings in income from their sales. So it is fun to cook.”

The biggest challenge that Chaff Energy is currently facing is that of funding and the unavailability of local materials to make the stoves. The stainless steel used for making these stoves has to be imported and is quite expensive. This basically inflates the cost of making these stoves.

The reason why they use it is because of the temperatures involved which about 1,000 degrees is. They are also quite durable with a lifespan of between 5-10 years.

“Currently, a small household stove sells for around sh. 6,000. The medium one is about sh. 10,000 while the institutional one that can cook for 6 continuous hours goes for around sh. 30,000 per unit, depending on the design,” he says.

You can reach Francis via  francis@chaffenergy.co.ke