2025-03-07

Making off-grid electricity cheap in Malawi

Dear Friends, Family and Compatriots:

  Just got back from my most recent trip to Malawi. This trip was mostly advancing our solar electric cooking activities. The basic concept is that if a solar home system with electric cooking can be affordable, then all of their other electricity needs will also be affordable. This is because cooking takes 10 to 100 times more energy than lights, cell phones, music, or TV. So if there is enough electricity for cooking, there is enough electricity for pretty much everything else.

  Technologically, we have pretty much solved that problem, but we also have to solve the organizational and financial aspects if we want to grow our activities to have a really big impact.

Climate Parliament neeting

   The beginning of my latest trip on the first of February was a "Climate Parliament"  meeting (https://www.climateparl.net/) on electric cooking being. While parliamentarians came from many countries, the meeting was held in Malawi. This meeting provided a pretty strong affirmation that we are doing the right thing with our off-grid solar-electric cooking work.

  At the meeting, parliamentarians from around Africa were invited to discuss for a couple of days, the prospects of converting wood and charcoal cooking to electric cooking in their countries. The first few talks discussed the problem and then described how it is hard to create a solution when many people don't have access to electricity. So when I gave a talk about our work which both provides the cooker and the electricity supply needed to power it, people were very happy to see that a solution was possible.

  For the second day, we did a cooking demonstration. People were sufficiently impressed that they wound up buy about 20 solar electric cooking systems from us: Mostly Malawian parliamentarians who wanted to use the systems in their constituencies.

  So word is starting to spread. And as it does, the support for what we are doing should gradually build.

Fine-tuning The Cooker Systems

   While the basics of both our cooker systems and lithium titanate (LTO) "forever" batteries are basically solved, there still is some fine-tuning to do to make the systems a little more efficient and durable.

  For the cooker systems, there are four things to improve: (1) Better programming of the cooker buttons to make them a little more useful and intuitive ... and labeling them in Chichewa (the local language), (2) Adding a circuit-breaker to protect against over-current and over-voltage, (3) Helping customers connect other devices to the system, and (4) Better follow-up, installation support and customer tracking.

  In addition, we should be measuring exactly how the benefits of the system change with larger and smaller solar panels, the addition of bigger or smaller batteries, changing usage patterns, and customer training.  This way we can understand how much to invest in these different system components in order to optimize cooking system benefits relative to costs.  We have funding from UK Aid to do this research, which is a big focus of our activities over the next six months.

Latest Round of "Forever" Batteries

 Well our latest purchase of LTO battery cells finally arrived at the end of February, and we are starting to assemble our latest round of batteries. 

  Some fine-tuning on the batteries that we have done includes: (1) Power use of the battery control circuitry has been made more efficient; (2) The data file records both the battery voltage and the voltage of the power source when the battery is fully charged (this is useful when the power source is being used both for the battery and other loads), and (3) Parameters have been adjusted to prevent overcharging from a high-current power source.

  The plan for this next round is to make about 300 batteries and deploy them in a research project that records usage for different customers with different systems. Then by about September or October I am hoping that we will have a pretty decent idea of which customers get how much benefit from which types of system configurations.

Combining cookers, pumps and women's collectives to increase benefits further

  Even though our benefit/cost ratio for cooking systems can be pretty good (i.e. about 3:1), it needs to be a bit better to attract the level of grant funding that we will really need to grow large. So we are always trying to get benefits up and costs down.

  A recent development along these lines is that the Joyce Banda foundation proposed collaborating on getting solar pumps to their women's groups. So we counter proposed a program where the groups would start with a large-capacity cooking system, and then during the dry season borrow one of the cooking system solar panels for solar pumping.

  The idea is if the groups can really focus on maximizing the utilization of the solar equipment for both cooking and pumping, then the benefit cost ratio can increase higher than if the systems are just being used for one or the other.

  The nice thing is, during the rainy season when it is cloudy and you want more solar panels for cooking, you don't need the solar panels for pumping. And during the dry season when you need a solar panel for pumping, you don't need as many solar panels for cooking because it tends to be sunnier. Thus it should be possible to sometimes borrow a fraction of the solar panels from the cooking system for pumping and still be able to do most of your cooking.

  In this way, the cool thing is that the solar system winds up both growing food and cooking the flood that you grow. This makes a great integrated impact story.  In fact, the cooking system can cook something like 1 to 3 tons of food per year, and the solar pump can easily grow enough extra crop harvest to provide for another 1 to 3 tons of cooked food per year.  

  So quite literally one $500 solar system can produce an extra one to several tons of food per year AND cook the food that is produced. 

 Pretty cool. But there is still a lot of work to be done to demonstrate this model and then measure its actual impact. 

  So stay tuned ....

Visit to Foshan, China

  Since Malawi is almost literally on the opposite side of the earth from California, I have a choice of which way I fly home: I can fly East, or I can fly West. If I fly West, I pass through Europe, or if I fly East, I pass through China.

  This time on my way back to Cali, I decided to fly East so that I could visit our solar electric cooker manufacturer, a small company called eWant, located in the city of Foshan in the South of China. 

  We were introduced to this company in 2021, when our clean cooking funders in the UK evaluated the cooker from eWant and liked it:

https://mecs.org.uk/blog/ewant-24v-dc-5-litre-cooker-fit-for-purpose-and-a-good-size/

  At that time, we had spent a couple of years trying to assemble cookers in Malawi and just couldn't make them last. So we got a bunch of the eWant cookers and have been using them ever since. eWant is a small, lean company, that is family owned by a father and son. The company has about 80 employees.

  They have been very good about adding customization to the cooker when we do orders of a thousand or more.  This latest round we had translated all of the buttons to Chechiwa (the local language in Malawi), and specified the particular programs for each button. So I was dropping by to verify that every detail of the programs was just right. I also brought a broken cooker from one of the villages, so that we could verify why it broke and how to help prevent such breakage in the future. 

  When I reviewed the latest prototype, there were a couple of remaining tweaks that we implemented. As for the broken cooker, we decided that adding a DC circuit breaker for $1.50 or less could help prevent the overcurrent that broke the electronic relays/switches in the cooker.

  In future versions, we will also tweak the operating voltage to give it a slightly larger range of operation. 

Refining and upgrading our off-grid solar cooking system

  As described in the April friends and family letter, we are now able to provide an affordable off-grid solar electric cooking system that has about 700 watts of solar panels. A couple of refinements and issues that need to be resolved before such systems can be distributed at scale include:(A) Is 700W necessary, or can the cooker system have fewer solar panels and be a bit cheaper, (B) How does the forever battery get incorporated into the system? and (C) How much subsidy is needed to make the system affordable to rural customers. 

  To answer question (A), we cooked hundreds of dishes on systems with more and fewer solar panels and pretty clearly verified that 600 to 700 watts of solar panels are needed to cook the 3 to 5 dishes per day that people will want to cook on sunny days. 

  To answer question (B), we distributed two competing systems to customers: (#1) A system with 700W of solar panels and no battery, and (#2) a system with a 350W solar panel and a 20V forever battery.  We are still analyzing some of the data that we collected, but it seems pretty clear that people can cook more with the 700W of solar panels and no battery than the system with a 350W panel and a battery.  Since the battery is more expensive than a 350W panel, then it is best to first sell a system with two 350W solar panels to start cooking and that add the battery later. 

  To answer question (C), we simply tried selling the cooker systems at different prices.  We found that if we sell the 700W system at $50, the demand is unlimited, while if we sell it at about $200, the demand is small, and so it seems that selling it for a little over $100 is the sweet spot.  This means that a little over $100 is the price at which we are now selling the 700W cooking systems.

  I also would like to note, that we can now get a 655W solar panel at the factory door in China for only $53.  By the time it is transported to Malawi, it costs about $75. With the voltage conversion electronics and the cooker added, the total cost of the cooking system materials is about $150.  So if we can keep the distribution cost down to about $50, the $100 price for the cooking system represents about a 50% subsidy. 

  We are getting close to being able to provide affordable off-grid solar electric cooking without too much subsidy. 

Going forward: near-term goals 

  We now have enough budget and resources to distribute about 500 cooker systems and 500 pumping systems over the next six months or so. We will also build and distribute about 300 forever batteries. This will benefit about 5,000 to 10,000 people.  This will be done with roughly $100K of donations, about $70K of research grant money, and about $100K of sales revenue. 

  We will measure and document in detail the performance of these systems and equipment. We will work to make continuing improvements in system efficiency, durability and cost-effectiveness. And hopefully we will be able to teach rural women's groups how to share the systems and operate them to maximum benefit. Then when our benefit-cost ratios get even more impressive, this should help us to get more financing to expand our work and impact next year. 

  Fingers crossed!

That's it for now ...

  Well that is it for now.  My next trip to Malawi will probably be in April/May.  

  And as always, THANK YOU for your continuing support. What I try to do is make sure that for every $1 that you donate, we produce at least $10 of benefit (on average) for low-income rural Malawians. And I am always trying to get this number higher all of the time. 

  Feel free to keep supporting us at:

https://www.omprakash.org/global/solar4africa/donate

In love and struggle, 

Robert VB