What’s the most cost effective way to power an LED lamp? How about by using gravity…?
Introducing the GravityLight. The GravityLight is an LED lantern powered solely by gravity so that it can be used over and over again with zero running costs.
The GravityLight was developed by Deciwatt, a product development initiative. The project began when inventors Martin Riddiford and James Reeves were challenged by the charity, SolarAid, to create a solar-powered LED lantern costing less than $10. They realised that using batteries in combination with solar power was not a viable solution, since batteries in particular incur significant costs and have a finite lifetime. So, how did gravity come to provide the solution?
The GravityLight works by allowing a suspended weight to gradually fall, pulled down by gravity. This motion is converted into electrical energy using a series of small gears. In essence the GravityLight facilitates the conversion of kinetic energy into light, and only requires the user to fill the accompanying durable plastic sack with earth or rocks to act as a weight before it is ready to function.
It is not just its simplicity that is remarkable; the GravityLight is also fantastically efficient. On the lowest power setting, up to 28 minutes of light can be expected from the 0.1W of power generated by lifting the weight and leaving it to fall just once. This is partly due to the absence of batteries, but notably made possible by the ever-increasing efficiency of LEDs themselves, producing light without wasting energy as heat as conventional bulbs do. On top of this, LEDs boast a lifespan of around 30,000 hours, trumping the traditional incandescent bulb, which usually lasts for around 750 hours. The exciting thing for Deciwatt is that as LED technology keeps on improving, so do the prospects for further models of the lantern.
So how do people benefit from using the GravityLight? Well, much of the world relies on burning hydrocarbon fuels as a source of light, namely kerosene. An overreliance on kerosene lamps presents an array of problems. Firstly there is the significant risk of fire, leading to 1.5 million cases of severe burns in India alone, and secondly, there are direct negative health effects from kerosene fume inhalation, equivalent to smoking two packets of cigarettes a day. It is no coincidence that an estimated two-thirds of adult females with lung cancer in developing nations are non-smokers.
Aside from the health hazards there are the relatively high costs of kerosene fuel to be considered, equating for some to 10-20% of their income; whilst the GravityLight may seem a high expense initially, it is mere months before the money saved overtakes the one-off cost of purchase – the GravityLight, remember, has no running costs whatsoever. Effectively this means in a short space of time, households in areas without reliable electricity supplies could be saving a hefty proportion of their earnings, as well as renouncing their ties to fossil fuels.
Also to be considered is the damaging environmental impact that accompanies the burning of hydrocarbon fuels. Using a single kerosene lamp for just 4 hours a day emits over 100kg of carbon dioxide, and it is also a waste of finite hydrocarbon resources. All in all, the GravityLight provides a sustainable replacement for the kerosene lamp. It is cost effective and safe, provides the means to work and study after dark, and will guarantee long term savings for those previously relying on kerosene lamps.
The GravityLight GL01 is currently being trialed worldwide, particularly in Africa and India where lack of reliable power supply has previously allowed no alternative to fossil fuels. The development of LED technology coupled with practical improvements to the design will only result in greater efficiency and sustainability for Deciwatt’s next generation of light and power sources for the developing world.
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