Gravity-Powered Light Offers Low-Cost Way of Seeing
Image:
By Ben Schiller
The GravityLight gets power from the slow lowering of a weight. All it takes is enough elbow grease to hoist the bag, and you can light a room with nothing but a bag of sand.
We're written about several projects delivering cheap electric light to developing countries. The need is enormous: more than 1 billion people still lack electricity, and many rely on kerosene--which is relatively expensive, highly polluting, and comes with multiple health and fire risks.
Many of the solutions out there are ingeniously solar powered. But GravityLight, an idea from two British designers, is something completely different. It gets its energy from gravity: a 22-pound bag of sand that gradually cranks a gear-train attached to a D.C. motor. One lift is enough for 30 minutes of light, and recharging is as simple of pushing the weight up again.
Martin Riddiford and Jim Reeves are crowd-funding the prototype on Indiegogo, and have already raised almost $100,000. They plan to distribute 1,000 units to villagers during a test stage, before developing and commercializing further. They estimate the current cost at $10 per machine, but reckon they can halve that by scaling up, and finding better materials.
The two initially worked with SolarAid, an NGO that wants to eliminate kerosene lamps in Africa by 2020, because the fuel is expensive and the fumes are bad for people's health when trapped in a small space. But they soon found that solar has limitations. One, panels and batteries are still relatively costly, especially for durable models. Two, batteries deteriorate over time, and need to be replaced. And three, you have to dispose old units, presenting a potential environmental challenge.
By contrast, GravityLight works inexhaustibly as long as you have the strength to lift it, and provides light whenever you need it. You don't need the sun to shine, or to store up enough power for evening's use.
"There is a lot of money going into solar, and it's being seen as the only way forward," Riddiford says. "What we're saying is there are lots of places that don't have enough sunlight to charge panels. If you have two or three dull days, you are running out of light."
The cheapest solar lamps, which include both panel and battery, cost only $5. But Riddiford says you don't get much for that--he calls the models "toys"--and there are costs attached, such as the price of replacing batteries.
He's not dismissing solar, though. "Once people have started saving money, after a year or so they might be able to afford a reasonable solar system, if they have enough sunlight," he says.
Riddiford and Reeves don't claim GravityLight produces a brilliant quality beam--it's just better than what's on offer at the moment. "Unfortunately the potential energy isn't that huge. But it is sufficient light, and it's free light, for someone who has no other access to electricity."
The illumination is equivalent to a kerosene lamp, he says, but can be supplemented with "task lights" running off the terminals at the bottom of the unit.
"You can do a Christmas tree string of lights extremely well. The strange thing is that you can light 10 LEDs almost as well as one LED. So, you can have general illumination and have task lights," Riddiford says.
It's nothing like being on the grid. But, as Riddiford says, it's already better than kerosene. During the testing phase, we'll find out how it stacks up against solar as well.
Copyright 2012 by Fast Company. Reprinted with permission.
See what we're tweeting about
9 Comments
Add Commenthow about just using a winding spring mechanism much easier and probably more portable.
Reply | Report Abuse | Link to thisHow easy/quick is it to store something like 150 Joules in a portable and reliable spring with human work? Might be no problem. I don't know. I do know what's involved in lifting a 10 kilo weight and about how long it takes. Also, a rope and a bag should be a more easily replaceable storage system than a spring.
Reply | Report Abuse | Link to this
Reply | Report Abuse | Link to thisThis is what I call a "win win" idea. There does not seem to be a downside for this kind of technology. A brilliant concept. Now lets find a way to get thousands of these things into the hands of people that need it.
Funny how SCIAM is always presenting hyped up stories on these mickey mouse, pretty much useless "ingenious energy solutions" but refuses to do any articles on REAL GREEN energy solutions like LFTR, Molten Salt Reactors, the Integral Fast Reactor, Accelerator Driven Sub-Critical Reactors, Pebble Bed Modular Reactors, Colliding Beam Aneutronic Fusion, Bussard's IEC Polywell fusion, Focus Fusion and a dozen other REAL ENERGY SOLUTIONS.
Reply | Report Abuse | Link to thisMight want to read up on the ownership of SCIAM:
ecofascism.com/article22.html
I don't know if it's good or bad that radicals are starting to post on every SciAm article I read online...
Reply | Report Abuse | Link to thisAnd your definition of radical is anyone who doesn't agree with you.
Reply | Report Abuse | Link to thisThis sounds pretty good, but it doesn't talk about how long one lift lasts, or how much light it puts out. How about a system where one person pedals continuously? There are many possibilities, once we recognise the problem.
Reply | Report Abuse | Link to thisThe article states that there is a duration of 30 minutes,with a light output equivalent to that of a kerosene lamp.I see no reason that you couldn't use a series of pulleys to lift much more weight in a safe manner of course,and thus produce much more power for a longer length's of time.This could allow other things like a TV's, radio's,stoves,and fans.As well as a brighter source of light.The list could go on to include many other devices that people may need.Such as power tools,and sewing machines,making what ever their manufacturing much more productive.This product could provide the power to make life better for millions,as long as the price of the devices doing the work remain low.It could be the start of an industral revlution from the bottom up.
Reply | Report Abuse | Link to thisMaybe the article was edited after you read it but it now clearly states that it lights up for 30 minutes per bag lift and generates light roughly equal to a kerosine lamp. That gives a range of 1 to 6 lumins. Probably not good to read by but fine for most domestic tasks.
Reply | Report Abuse | Link to thisI'd like one or more for my home.