Did you know that there are currently over 1.5 billion people in the World who have no reliable access to mains electricity? These people rely, instead, on biomass fuels (mostly kerosene) for lighting once the sun goes down.
A commonly held view is that solar powered lighting is the answer to these problems in the developing world. However a number of conflicting factors combine to complicate matters. Solar panels produce electricity only when the sun shines, so the energy needs to be stored in a battery to produce the light when it becomes dark. The amount of energy stored is dependant on the size of the panel, the size of the battery, and how much (if any) sun has shone.
However batteries, panels and lights are expensive, and beyond the reach of people with no savings. Solar lighting projects continue to provide lighting for thousands of people in the developing world, but the spread is slow because the cost is too high for individuals, so they need to be bought and installed by communities instead.
Lower cost self-contained lamps are becoming more widely available, but batteries are the weak link, because they are expensive and deteriorate through use and over time. Very often, when buying a low cost solar lamp with an inbuilt rechargeable battery, a full third of what you’re paying for is the battery, and you will need to replace it every few years. Assuming you can get a new battery… The capacity is often reduced to save money which limits the use time, after which there is no light.
With GravityLight, however, it only takes a few seconds to lift the weight, which creates enough energy for half an an hour of light, whenever it is needed. It has no batteries to run out, replace or dispose of. It is completely clean and green.