DAVID WAIRIMU can finally do his homework. An innovative solar-powered
lantern allows him to carry on working when it gets dark. 鈥淢y position in class
is much better since we got it,鈥� he says. David, who is 14, lives with his
mother Margaret in a mud-walled hut in Engashura, near the town of Nakuru in
Kenya.
Electric lights gleam in Nakura, but Kenya鈥檚 ramshackle electricity grid does
not reach 90 per cent of the country鈥檚 homes, including those in Engashura.
Until last January, the family鈥檚 only light at night was a hurricane lamp
burning kerosene. 鈥淚t was too dark to read by,鈥� says David, who proudly displays
his new hand-held lantern and points out the cable connecting it to the solar
panel on their thatched roof. 鈥淲e recharge during the day, and that provides
electricity for an evening鈥檚 light,鈥� says Margaret.
The Glowstar lantern is the brainchild of a British non-profit consultancy
called Intermediate Technology Consultants. After trials in Kenyan homes, the
lamp was launched commercially this month. The hope is that it will do for rural
African lighting what the clockwork radio has done for its
listening鈥攑rovide a cheap, reliable, ecologically friendly product that
does not require mains power, expensive batteries or kerosene.
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The solar lantern kit, which costs around 拢70, is a purpose-built
sealed unit containing its own rechargeable battery. What makes it unique is a
new type of microchip charge regulator. Its designer, Kieron Crawley, says the
regulator will be the key to its success, where other attempts to harness solar
power have failed. Around 150 000 Kenyan households have tried using solar
panels to charge up car batteries and run portable TVs and lights, but many have
abandoned the equipment as batteries became exhausted owing to the use of poorly
designed charging circuits.
ITC鈥檚 microprocessor based charge-control circuit housed inside the lantern
constantly monitors the battery to ensure it remains charged. At night it will
switch the lantern off rather than allow the battery to go flat, and it can
control how much solar energy is conveyed from the solar panel to the battery
during the day. 鈥淓xisting systems don鈥檛 do this effectively,鈥� says Crawley. 鈥淎s
a result, performance gradually drops off and within six months the system is
诲别补诲.鈥�
There have been teething problems during the lantern鈥檚 pilot phase. 鈥淲hen the
battery runs down the chip loses its memory and the whole thing has to be
reprogrammed back in the UK,鈥� says Bernard Osawa of Nairobi consultancy Energy
Alternatives, which has audited the pilot.
But Crawley is confident the problems have been sorted out. Few doubt that
solar power has massive potential in rural areas of the developing world that
are excluded from national electricity grids. After all, millions of children
like David are waiting to do their homework.