07 Jul 8.2 The “Namaste” Solar Cook Stove
Cooking was clearly the most dominant energy consuming activity in the village households. Even if all the kerosene that the villagers procured had been used for lighting and none for kindling cooking fires, 3 liters of kerosene per household per month works out to at most 0.1kg of kerosene per household per day. But the villagers were using 10-20kg of firewood per household per day, which is 50 to 100 times the carbon content of the fuel used for lighting. The Lighting Project became Climate Healers.
Worldwide, nearly 3 billion people use some form of biomass for cooking, burning up an estimated 1.5 billion tons of firewood annually. That is the amount of wood that would grow on about a billion acres of land in a temperate region, each year, if left alone. This statistic is a searing indictment of Catapilism, the distorted version of Capitalism that is dominating the global economic system today. Massive investments are being made in the endless production of entertainment gadgets for the rich, but very few investments are being made to satisfy the basic needs of the poor. Since Life is dying in the process, it couldn’t be enlightened self-interest that is driving the economic engines of the world, but its very opposite.
Instead of cooking on a three-stone fire, if the villagers used more efficient cook stoves, their firewood use could diminish, but there were several problems with that approach. Firstly, such efficient stoves depend upon the firewood being of the right size and type and if it is not, the efficient cook stove could belch far worse smoke than the traditional approach. Even in these remote areas, firewood smoke contains industrial effluents since the trees have been filtering our industrial pollution from the rain water and storing it in their trunks over the years. And efficient stoves require a steady supply of oxygen in their air intake, which becomes a problem in indoor settings, especially if the air intake path is clogged with ash.
Secondly, energy use among the poor will necessarily increase as they develop and treating the cooking problem as just a stove efficiency problem leaves the source of their energy the same – firewood. This means that we would eventually need to address the energy source issue even if we provide them with technologies to burn firewood efficiently. Therefore, we decided to help them tap into an alternate source of energy that is falling plentifully on their heads – solar.
Faced with the task of supplying a solar stove that can cook rotis made from various local grains such as Bajra, Jowar and corn, in addition to boiling rice, lentils and vegetables, we hired an engineering firm in Ahmedabad, India to either procure or design such a solar cook stove along with an electronic mechanism to meter its use. The meter was to measure the number of hours that the cook stove gets used so that the user can be compensated at a proposed Rs. 2 per hour as an incentive, which can be financed through a carbon credit mechanism. Cooking rotis is a little tricky: if the time taken to cook the roti is too long, then it becomes hard and inedible and if it is too fast, then the insides would be uncooked even as the outer skin gets charred. There is a Goldilocks range for the power requirement depending upon the grain and thickness of the roti, and it was around 1 kW. But every existing solar cook stove that could supply 1 kW at its cooking surface was huge and we couldn’t stand near it to flip the rotis. These stoves were all of the parabolic kind that concentrate the solar energy falling on their reflectors to the center, but the energy leakage was so high that more than half that energy wound up cooking the cook.
The “Namaste” Solar Cook Stove design mainly had to improve the efficiency of existing solar cook stove designs, while engineering it to be foldable and portable so that the user can put it away in a corner of their hut after use. The efficiency was improved by adding a shielded metal skirt at the focal point of the parabola so that the thermal energy is trapped by convection currents. The design was made foldable in the same manner as in the “Butterfly” cook stove, by splitting the parabola into two separate halves. And we added wheels to make it portable. We called it the “Namaste” stove since in its folded state, it resembled the Namaste gesture of greeting that people in India use with folded hands. Folded hands resemble the flame of a candle and the gesture is used to acknowledge the Light or the Atman within another.
The first prototype was deployed in Karech, Rajasthan, in September of 2009 and after incorporating some feedback from the deployment, 5 more cook stoves were deployed, four in Rajasthan and one in Hadagori, Orissa in January of 2010. More detailed feedback was collected from the villagers six months later. Unlike the solar lights for which the feedback was overwhelmingly positive, the feedback in the case of the “Namaste” solar cook stove was overwhelmingly negative. Here is a compilation of the villagers’ reactions to the stoves, gathered through my personal visits and through FES personnel:
1. The solar cook stove is difficult to use in hilly terrain without leveling the ground.
2. It is uncomfortable to stand facing the sun to cook without an umbrella shade.
3. The cook stove is too tall for the women who actually prefer to sit and cook.
4. The solar cook stove requires constant adjusting which makes it inconvenient to use.
5. It is difficult to use the solar cook stove within the normal routine of the village women, since they are rarely in or around the house during the day. One villager even said to me, in effect, “Why did you do the cooker differently from the solar light? With the solar light, we left it on top of the hut and went to work. When we came back in the evening, it was ready to use. The cooker didn’t work the same way”.
6. The solar cook stove is difficult to use with a child in arm or a youngster in tow as it requires the user to stand and stretch to reach the cooking surface.
7. The solar cook stove is unstable and topples over in windy conditions, spilling the food.
8. The solar cook stove can only be used outdoors and during day time when the woman has various unending chores to tend that center around her children and animals.
9. Since the solar cook stove was only given to a few families in the villages, the recipients felt left out of the social activity of gathering firewood in the forest in the company of their friends.
Though most of this feedback is applicable to any parabolic solar stove design, the net result was that over time, the “Namaste” solar cook stoves were moth-balled in the villages. This experience was so unlike that with the solar lights which continue to be treated as the prized possession of each household. In that context, the villagers’ feedback has been truly humbling. In the prototype deployment, we did not install meters to measure the stove usage and provide incentives for the users, but it is unlikely that payments on the order of Rs. 2 per hour of usage would have improved the feedback substantially. This is especially because the Indian Government has instituted the National Rural Employment Guarantee Act (NREGA) program in these villages and as a result, households are earning an additional Rs. 100 per day which dwarfs our proposed incentives.
 This estimate is based on the FAO projection that half the wood consumed annually is burnt as fuel worldwide. http://www.fao.org/docrep/004/y3557e/y3557e10.htm .  From the Climate Healers Project Report from August 2010, which can be downloaded from https://www.engineeringforchange.org/workspace/view/22/1#tabs=/workspace/files/22/1  http://nrega.nic.in/netnrega/home.aspx