The GravityLight was created by London designers, Martin Riddiford and Jim Reeves. GravityLight is a small LED light powered by gravitational energy. The user lifts a weighted sack filled with rocks, gravel, etc. The sack slowly descends, providing light for up to 30 minutes. The device is even configured to charge various electronic devices. The light currently costs only $10 and could drop to as little as $5 with mass production.
As many as 1.3 billion people lacked electricity in 2009. These people rely primarily on kerosene lamps to provide nighttime lighting. These lamps have numerous downsides: negative health impact from particulate matter exposure, child poisoning due to accidental ingestion, etc. In Sri Lanka, 40% of all burns are attributed to kerosene lamps, with 150-200 lives lost, and a medical care cost of $1 million annually.
Furthermore, as much as 10-20% of household income is spent on kerosene for lighting. At a cost of $10, the GravityLight takes only 3 months to pay for itself in kerosene savings. The GravityLight will continue to save money for the user. With these savings and the increase in possible productive hours, the user might be able to lift themselves out of poverty.
A typical LED light offers similar performance to that of the brightest kerosene lamps, with potential to be considerably brighter than the typical lamp. Fuel-based lighting, typically kerosene, represents $38 billion per year fuel costs and 260 MT of carbon-dioxide emissions worldwide. The GravityLight runs on a fuel that is free, gravity. Because it does not use hydrocarbon combustion, it does not generate any carbon-dioxide.
The GravityLight offers a promising solution to the economic, environmental, and health issue of off-grid nighttime lighting. It offers improved economics by saving the user money on fuel costs. It offers a clean and safe alternative to burning kerosene for light. Even better, it accomplishes all the above while providing improved illumination when compared to typical kerosene lamps.