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Agriculture

Published on August 12th, 2019 | by Jesper Berggreen

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How Solar Power Finds New Uses In Rural Africa — The Solar Hammer Mill

August 12th, 2019 by  


On my recent visit to Zambia to visit friends and family, and not least to visit my old local school in Mapanza village, Chibwe Primary School, I noticed a bright blue building close to the guesthouse I was staying.

Solar Powered Hammer Mill

According to Lusaka Times, in 2015 the Zambia Cooperative Federation (ZCF) began installing 2000 solar powered hammer mills used to make maize flour. The bright blue building I had spotted from the guesthouse turned out to be one of them.

The guesthouse manager Mr. Leo Mudenda told me it seemed to be unoperational, but he would try to locate the man who was in charge and ask him to come and give me a tour of the system.

Dusty Solar Panels

The harvest in southern province in Zambia has failed completely this year. It is devastating to rural farmers, who can only hope for government relief before all spare stock of maize is used up and the dry season peaks in October. Many people are in risk of going hungry otherwise. Maybe not full scale starvation this year, but the next harvest in 6 to 8 months better be good, otherwise the region will be in serious trouble.

The situation is dire, and my old friend Mr. Anderson Mushabati confirmed this. At the age of 85 years he is still producing oranges at his farm nearby with a clever system of irrigation from the river, which unfortunately is also running dry, resulting in his oranges not getting the water they need. The rainy seasons starts later than usual he claims, and stops too early. Climate change is a daily topic, but not so much the reasons for it.

While we were discussing the drought, the operator of the mill, Mr. Milimo Sianjelele, came by and offered to show us the solar powered hammer mill. He told us a total of 50 mills had been installed in the province, but the mill he was in charge of had not been operational for 4 months. A sensor of some sort was broken, and though the spare part had already arrived, they were still waiting for a Chinese technician to replace it.

In any case he could still show us the workings, so he fired up the system. Outside the blue building 50 very dusty solar panels are installed, and to my surprise they produce a total of 10.7 kW of power at this time just past noon. I had guessed each panel to output about 200 W had they been clean, but I guess maybe these were 250 W panels and the dust was reflecting 50 W of potential power.

Inside the building a massive inverter system took care of the incoming power, and the mill itself had a battery backup that slowly started charging as we went through the nobs and dials of the mill.

Mr. Sianjelele had no idea when the mill would be operational again, and this comes as no surprise giving the lack of reliable communication in remote areas like this. Indeed there is cellular connectivity, but the logistics of getting a Chinese technician out here, and let alone knowing when, can be a challenge.

Mr. Mushabati shrugged at the whole thing and said: “I’m fine with my old diesel engine pump at the farm. At least I can repair it myself!”

Well, that may be, and maybe these mills are a bit more complicated than the need to be, but you can’t deny the solar potential in regions like these. 5 years ago when I last visited the area there were no solar power installations to be seen anywhere, and of course back in 1981 when I was a kid here, no one had ever heard of such things. Now, massive multiple MW solar power plants are being installed in Zambia, and combined with the hydro power available it makes a lot of sense.

Zambia Is The Perfect Hydro/Solar Hybrid Showcase

Due to the lack of rains, daily electricity load shedding was in effect. Only that way would water have time to build up at the massive hydro power plants at Kariba, Kafue, and Itezhi-Tezhi dams, which combined with a few other plants have a peak capacity of more than 2 GW.

A few 60 MW solar photovoltaic plants are being built in the country right now, as part of an initial 600 MW government mandate, which has set the goal at a total electricity capacity in the country of 6 GW by 2030. The reason this is so clever in places like Zambia with a lot of hydro power and a solid built grid, is that the dams will in effect act as huge batteries that “charges” by holding back water, while the very reliable sun provides power during the day. Pumped hydro is not an option here. As the sun sets, you simply turn up the flow of water. And since Zambia has 8 neighboring countries, a system of power trading is already well established.

I have a feeling that I have seen the last load shedding in this place. If I come back in 5 years, I am sure this country will have a very stable grid.

All photos by the author. 
 





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About the Author

Jesper had his perspective on the world expanded vastly after having attended primary school in rural Africa in the early 1980s. And while educated a computer programmer and laboratory technician, working with computers and lab-robots at the institute of forensic medicine in Aarhus, Denmark, he never forgets what life is like having nothing. Thus it became obvious for him that technological advancement is necessary for the prosperity of all humankind, sharing this one vessel we call planet earth. However, technology has to be smart, clean, sustainable, widely accessible, and democratic in order to change the world for the better. Writing about clean energy, electric transportation, energy poverty, and related issues, he gets the message through to anyone who wants to know better. Jesper is founder of Lifelike.dk.



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