This weekend I was reading MIT Technology Review and an article about the problem with lighting in Kenya – specifically, the cost of lamps to provide light at night. Although the devices were inexpensive (under $10), the cost of kerosene fuel was continuous, as well as the problems with burning petrochemicals in an enclosed space.
One solution: Solar powered lanterns. Lower operating cost, at least as long as the battery lasts. Downside is the cost for parts – $23, according to the article. However, the benefits are significant: Less health and respiratory issues, and a quick savings, since no ongoing expense purchasing kerosene. And although the battery may fail eventually, solar cells are long lasting, and the light source (LEDs) are often rated in the 10-100,000 hour range before failing (to do the math, at 8 hours of light each night, a 50,000 hour LED would fail in over 17 years).
However, I started wondering if I could do better – after all, $23 is still a lot. And although I had already written about the water battery in my manifesto, water is rare and precious in Africa, so they needed something else.
Why not then a weight? For example, winch a weight up a tree, and let it fall slowly while it turns a generator. When it reaches the bottom, winch it up again. Use any motor, some rope, and some place high – you have power. Start by winching it up by hand, but if there is any power source available (wind, solar, etc.) redo the setup to allow reversing the motor, and have it raise the weight. When the sun sets or wind dies, reverse the motor and generate power.
None of this is ground breaking (except I suppose the weight falling if the rope breaks). If you’ve ever studied an older grandfather clock, you’ll see a weight that has to be raised often – the falling weight is what powers these versions of the clock. Fancy spring-wound mechanical wrist watches are another example – just a spring instead of a falling weight. The catch is making it simple and easy to use in the Third World.
Fortunately, we don’t have to ‘weight’ too long for options – one company funded a successful Indiegogo offer in early 2013, and has released a gravity powered light (called unsurprisingly GravityLight). You can see the offer here and the site here. Since they raised over seven times their original $55k request, others obviously feel this is an idea whose time has come.
Where to go from here? Personally, I’d love the time and resources to explore this problem properly, and design a winchable weight generator that anyone can build, then put the plans online and make it simple for anyone with access to an old alternator or fridge motor to make. Lighting is only one aspect; for example, if the design is simple enough, people can offer charging of cell phones, and start a lucrative (for Africa) business. And with ready access to power, uses will be found for it – think of it as Parkinson’s Law for electricity, where power uses expand to fill the electricity available for it…
In the meantime, however, it’s great to know people are tackling these problem using simpler solutions – solutions that are practical for third world countries.