Solar cooking for everyone

How to reduce CO2 emissions equal to 200 millions cars?

We often hear about how the energy-sector and the transportation-sector contribute to CO2 emissions. But deforestation is in fact the second largest source of CO2-emissions. Of a total of 33,4 Gtonnes, 18% of is due to deforestation in the world. This is actual more than than the total emissions from all the world's planes, ships, trucks, and cars!  (PNAS, UNEP, REDD+)

In Norway we are for the moment discussing CO2 reduction in the range of 8 million tonnes. This is 0,05% of what we need to reduce in order to save the planet. Compared to our population, it is 1,6 tonnes of CO2 per individual and about 50% of what each individual on the planet needs to cut down on CO2. Compared to our total emission, which is 10 tonnes per individual per year, this is 16% of our total CO2 emission. But for many people in developing countries, 1,6 tonnes of CO2 is more than 100% of their total CO2 emissions!  It seems therefore that the richest countries in the world must take on themselves much more responsibility than the poor ones if we are going to succeed.  Politicians are pulling in different directions, and we are only discussing fractions of what we need to do. Where is the global systematic approach of how and where the cut should be made,-  in which sector, in which areas and so on? As I mentioned, deforestation is one of the areas where there is a great potential to cut down on CO2 emissions.  With relatively small investments, I’d like to point out how we can cut down on CO2 emissions, equal to 200 million cars on the road.

The worlds' forests are covering about 30% of the world and contains about 2000 Gt of CO2, and is one of the greatest sink of carbon in the world. FAO estimates that 13 million hectares are converted to other uses or lost through natural causes annually. Forest area increase are about 5,7 million hectares, and net deforestation about 7,3 million hectares.

According to UN and the Global Alliance for Clean Cookstoves 3 billion people are still using woodfuel and charcoal around the world for cooking - and the number is rising. The estimates of woodfuel consummation is between 0,5 and 2 kg per person per day according to WHO. In average we should therefore be rather moderate to calculate 0,6 kg per person, which gives a total consummation of about 660 million tonnes woodfuel in households a year. But how much is really 660 million of tonnes? Can we put it into another figure that is more easy to understand? Maybe if we could translate it into hectares of forest? As a world-average, one hectare of forest gives about 131 m3 of woodfuel (FAO, 2010) or 79 tonnes per hectare forest. 660 million tonnes of woodfuel / 79 tonnes per hectare then gives 8,3 million hectares. As one hectare is 100*100 m this gives us 83 000 km2 of forest or a square of forest that is 288 km in each direction. This is the total deforestation by using wood and charcoal for cooking.  

The ancient tradition of cooking, consumes 1 million hectare more than the world net deforestation! To put it in another way, if we could completely replace woodfuel and charcoal with green energy in households around the world, there should be no more deforestation in the world, but a positive net forestation of 1 million hectar per year, which will increasing CO2 mitigation substantially. 

Most of the deforestation today are in areas where cooking with woodfuel are dominant. In many African countries, close to 90% of their energy consummation is related to cooking food. Africa have for instance only 17% of the worlds’ forest but a net deforestation of 4,3 million hectares.

Billions of dollars are spend on different political projects to protect the forest, but many times corruption and lack of transparency and willingness to follow through fails on the ground. And there is another problem, the market demand. 3 billion people are using wood and charcoal every day for cooking purposes, and where there is a demand, there will always be suppliers. As long as these people still uses wood and charcoal, the consummation of wood will be intact. It's true, it's a daunting task to change this. But, I think we can and I think we should be able to change it. Serious health issues are also at stake here. 4,3 million people, many of them children are dying each year because of illnesses caused by smoke from traditional stoves. (WHO, 2014)

Solar cooking is in its infancy, but has been more and more popular in recent years. India is now planning to set up solar cookers on 500 000 schools! That will affect millions of people and millions of students and homes will be introduced to solar cooking. That can make an impact in the long run and maybe turn the tide for solar cooker in that region.

Solar energy is the only alternative that is CO2 free and should be used whenever possible. But what is the price-tag and how does solar cooking compares to other projects to reduce CO2 emissions? It is our children who will pay the ultimate price if we don't act. It is not a question whether we can afford it or not, but if we can afford to do too little. All future generations are at stake. Still, lets look at one example.

According to Solar Cooking International there are about 600 million people that can make very well use of solar cookers. They are living in areas where there are plenty of sun, and they have great difficulties in finding firewood or charcoal at a decent price.

Distributing solar cookers to these people groups will require about 150 million solar cookers. Distributing solar cookers at 10 $ each will cost 1500 million dollars to cover for production cost for the first years, and businesses and value chains will have to be established as well. Consumers will eventually pay for their own solar cookers. As we find sustainable business models, the total cost can also be much lower. Still we can save 1200 million tonnes of CO2 each year or 7% of the CO2 we need to save before the year 2050 to keep the temperature increase below 2 degrees C. Is the price tag too high? If you look at the alternative, the question is not whether we can afford it or not, but if we can afford to do nothing. It is our own children that eventually will pay the ultimate price. But nevertheless, lets compare the price-tag to another project, the Ivanpah project in Las Vegas.

The Ivanpah project is the worlds largest solar plant of its kind and is constructed by 347 000 sun-tracking reflectors. It has a bill of 2000 million dollars and can produce close to 400 MW electricity. At the same time as it gives electricity to 140 000 homes, it can also save the world for 400 000 tonnes CO2 a year. This represent 72 000 cars on the roads.

A rough estimation of a solar cooker project that aims to reach 1/5 of those who today use wood and charcoal for cooking can save 1200 million tonnes of CO2. That is 3000 times as much as the Ivanpah project at a lower price-tag, and represent a removal of CO2 equal to 1/5 of all the cars on the planet - 200 million cars! Replacing unsafe cookstoves with modern alternatives is truly the 'low-hanging fruit' of environmental fixes" as US Sen. Susan Collins just said. It is time for not only India to understand the importance of solar cooking!

Views: 174


You need to be a member of SolarCookers to add comments!

Join SolarCookers

Comment by Magnar on June 3, 2014 at 2:10pm

Here is a simple solar cooker, that will heat the water in the PET bottle all day long. UV light will come in from all directions as well. The plastic bag should be attached to the spring and inserted into the bottle in order to gather as much solar energy as possible. Since the absorber is inside water, all the energy will be converted to heat.

- Magnar

Comment by Magnar on June 2, 2014 at 9:24am

I have made a design of a very simple solar reflector here and here that is very suitable for heating 10 liter PET bottles.  I used this design myself to heat water in Congo.  It is a smaller version of the Kolamba Solar Cooker, but temperature can still reach 145C in Norway (!) in a plastic bag and 135 C without.  You just cut out from  this template - it can be made of sheet metal of plastic. 

Another way to heat water with just the sun can be done with a plastic bag alone as I did in Djambala some years ago.  But this will not heat the water enough to pasteurize it.  

With a big reflector, water got UV sterilized and pasteurized reaching quickly a temperature of 70C. But a smaller reflector like the Kolamba Solar Cooker will also work after some hours.  More research needs to be done to know exactly what it takes to pasteurize water though. 

A clean plastic bag into the bottle could probably be used to speed up the process, as this will absorb the sun and convert it into energy much quicker. At the same time the plastic bag should not block the UV light, so it is a bit tricky to find the best way.  

Maybe a type of spring, like this one for example, or some sort of twig, could be inserted into a black plastic bag that is already in the PET bottle to spread out the plastic bag inside the bottle. This will convert sunlight to heat and at the same time give room for UV to sterilize the water.  Inside one of my reflectors UV-light will come in from all sides, so the plastic bag that sits in the middle of the bottle will not block the UV effect.  What do you think? 

All the best, 


Comment by Stefan Karnebäck on May 29, 2014 at 4:22pm

Hi Magnar

We've been in Cameroon for almost two weeks now and there is a great interest for solar cooking. This is just a survey we are doing for water disinfection, but we've used solar energy for that purpose. Cameroon has a lot of aluminium! You can read a little bit on our project site:

And you can contact Vise Chen who is CEO of the organisation Leéiyen Systems. It's an NGO and they do not have much funding but a lot of energy and devoted people,

I wish you all the best


Comment by Magnar on May 9, 2014 at 1:11pm

Thank you Stefan!  We are looking for partners to make the next steps.  We only have prototypes of our solar cooker, and need financing to carry on.  Please also check our website, for more information. :) 

Good luck in Cameroon! Please keep us posted on the next development there!

all the best,  Magnar 

Comment by Stefan Karnebäck on May 9, 2014 at 1:02pm

Great description, Magnar. What's the next step? Are you into the business of starting "local factories" in Africa? I am going to Cameroon next sunday and will take the opportunity to discuss this with that organisation. Our main purpose is water disinfection, but solar cookers is the common issue.

Good Luck!

© 2016   Created by Magnar.   Powered by

Report an Issue  |  Terms of Service