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Cheap, green solar bottles light up Kenyan slum

by Pius Sawa | Thomson Reuters Foundation
Friday, 21 February 2014 11:34 GMT

Pupils at Anajali primary school in Nairobi’s Kibera slum study with the aid of solar bottle lights in their classrooms. TRF/Pius Sawa

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Solar bottle lights are catching on fast in Nairobi's Kibera slum and beyond, as an inexpensive alternative to electric bulbs - and they cut carbon emissions too

NAIROBI (Thomson Reuters Foundation) – It’s a hot afternoon in Nairobi’s Kibera slum, but 32-year-old Michael Matare is comfortable in his tiny room. The house is brightly lit by two plastic water bottles jutting out of the ceiling. Between them hangs a 100-watt bulb, but it isn’t needed.

"Since I got these solar bottles eight months ago, I don’t switch on the bulb," said Matare, who is unemployed and spends most of his time indoors.

Matare said electric bulbs produce too much heat, making the house unbearably stuffy during the day. Before, if he didn’t turn them on, the house was dark, and he had to use a candle or kerosene tin lamp. But now he can get by with his solar bottle lights, which even function at night if the moon is bright enough.

"The solar bottles are very good because they save energy during day, and I don’t need to buy candles and kerosene to light the house," said Matare.

Matare, who has a wife and four children, is one of an estimated 1 million people living in Kibera on less than a dollar a day. Previously, he paid 400 Kenyan shillings ($5) a month for an illegal power connection. His monthly rent ranges between 2,500 and 3,000Ksh ($31-$37) - very expensive for people like him who rely on casual work, such as digging water trenches, for around 150Ksh a day.

That makes cheap, green energy technologies, like the solar bottle lights in Matare’s home, welcome here. The initiative - which began in Kibera last April and is sponsored by a group of students from Britain’s Durham University - is spreading fast in Nairobi’s slums.


The concept was first developed in the Philippines, and recycles clear 1-litre plastic soda bottles. These are filled with water, leaving a small gap to allow the water to expand when it heats up.

A round hole is made in the roof and the bottle inserted with its top sticking out. When sunlight hits the bottle, the water reflects it down into the house. Bleach is added to the water to keep it clean.

“We did a survey early in 2013 and we found that the community wanted (the lights) but could not afford them,” said David Ochieng, who is spearheading the project in Kenya through a nonprofit organisation called COVIT (Connecting Voices of Inspiration for a Better Tomorrow).

It launched with 250 bottles, but as demand shot up, the students raised more funds from their “Enactus” network for an additional 2,500 bottles.

The cost of making and installing one solar bottle light is around 200Ksh ($2.50). COVIT is also lobbying politicians and other potential backers to find more financing.

“We have so far installed 7,200 bottles in four villages in Kibera slum, and we are targeting between 50,000 and 100,000 bottles in Kibera,” said Ochieng.


The bottles have benefited not only individual households, but also community institutions, including Anajali Primary School and Hope Academy.

“We found that this saves our energy during the daytime. Instead of putting on the lights, we use the bottles, and the classes are bright and our children can see well,” said Valencia Otweche, a teacher at Anajali.

Previously the school spent as much as 10,000Ksh ($123) per month on electricity bills, which led to power disconnections because it couldn’t pay and the children’s parents are too poor to contribute.

Teacher Valentine Mongoi from Hope Academy said the solar bottles are a real blessing. “This has helped us have light in our classrooms. During the rainy season, the classrooms got very dark, but now the bottles give light and the children see when they are doing their work,” she said.

Each school has around 50 solar bottles - two to three per classroom depending on the size of the room. Children in the slums now spend much of their time at school studying, including weekends.

“I feel that the project should be advertised to so many people in our country so they can make use of it,” said Otweche.

Matare agrees. “These bottles can help even in the rural areas where people don’t have electricity, including schools, because they give very bright light during the day,” he said.  


The initiative, now known as Solar Project Kenya, has been rolled out to other counties across the country, including Mombasa, Busia, Kisumu, Migori and Kisii.

“We are targeting vulnerable communities, and we want to install the bottles in at least 400 homes per county,” said Ochieng.

The solar bottles can be fixed up in any house including thatched homes, he added. One bottle is enough for a 10-by-10-foot house, and it can last for up to 10 years.

According to expert estimates, one bottle provides light equivalent to a 55-watt bulb, and can reduce 575g of carbon emissions per day by cutting electricity consumption.

In Mombasa, 120 bottles were installed on the first day in mid-February. Demand rose to 600 the following day, according to Ochieng.

In order to reach more people, the project is working with youth groups. Three youths are selected to undergo training, and they are then expected to train others. It takes about five minutes to fix up one solar bottle depending on the type of roof, Ochieng said.

In Mombasa, the team has also enlisted community health workers, as they tend to be older people who know which households need the lights. They identify the recipients, while the youths install the bottles.


The biggest barrier to expanding the scheme is a lack of funds, combined with an expectation that NGOs should be handing out stuff for free, Ochieng said. In Mombasa, some areas also have salty water which isn’t good to use in the bottles, and that means spending extra money on buying fresh water.

“We cannot keep relying on donors and volunteers,” Ochieng said. “If people could sacrifice and contribute towards the cost, I am sure we can reach many families.”

Ochieng has also struck a deal with the Kenyan subsidiary of French petroleum giant Total to buy solar lanterns that provide light at night, at a wholesale price of 920Ksh each. The NGO sells them on for 1,200Ksh, putting 50Ksh of the profit into the solar bottle account, enabling more connections.

Another problem is conflict between tenants and landlords who worry that their houses will be damaged by cutting a hole in the roof to fix up the bottles. They have to be convinced that the solar lights will lower the cost of buying candles and reduce accidents caused by fire.

But Ochieng isn’t easily deterred. “I am sure our solar bottle project is one of the initiatives that can help save our continent from the effects of climate change,” he said.

“We are going green, and I am looking forward to Kenya being a solar project ‘village’ and a place where there are no more fire accidents due to the use of kerosene lamps and candles,” he added.

Pius Sawa is a freelance science journalist based in Nairobi.

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