What’s not to like? My mind was set racing after reading about Max Donelan’s “energy harvester” in the Economist recently:
The “energy harvester” that Max Donelan of Simon Fraser University and his colleagues describe in this week’s Science looks like an orthopaedic knee-brace. It tucks behind its wearer’s knee and has extensions that strap around the front of his calf and his thigh. When the wearer walks, the knee’s motion drives a set of gears which turn a small generator.
On the face of it, that sounds like a recipe for making walking difficult. Surprisingly, it is not. Although the leg muscles perform “positive” work when they accelerate the leg forward to begin a step, when the leg straightens at the end of the step they perform “negative” work as they slow the leg down. If the generator in the harvester were connected during the accelerating phase the process would, indeed, be expected to increase the load on the muscles. But if it were connected only during the decelerating phase it would impose no load. It might even make things easier.
(The BBC website has a video here.)
The potential for this kind of power generation seems vast, especially in the developing world. Not only could it prove to be a robust and portable personal power source , because it doesn’t rely on a centralized infrastructure it is at once an empowering technology (excuse the pun) and without negative environmental consequences. Not only could individuals in places like rural Africa and India have free (beyond the inital investment in the equipment) access to power for things like lighting, mobile phones, and even networked computers or even femtocells, they would not be emitting any greenhouse gases, and insofar as they could replace dirty fuel burning lamps with LED lighting, pollution would even be reduced.
One of the biggest changes has been the use of light-emitting diodes (LEDs). This has transformed wind-up lighting products, says Rory Stear, chairman of Freeplay Energy, which specialises in such “self-powered” devices. The company’s Indigo lantern, for instance, can provide up to two hours of light from just one minute of winding. LEDs also last for a long time: those in the Indigo are rated for 100,000 hours, whereas a filament bulb might burn out after 16 hours.
Such products can make a huge difference to power-starved people. Freeplay’s charitable foundation reckons that the use of kerosene, candles and firewood for lighting absorbs 10-15% of monthly household incomes in sub-Saharan Africa. It is planning to test a range of wind-up LED lanterns in Kenya and South Africa this year. These, it hopes, will allow people to do things like studying at night, increasing their security and coping better with medical emergencies. Freeplay Energy is also developing self-powered medical equipment, including a fetal-heart monitor.
Imagine this married to the emerging global carbon markets, and you can imagine a day not so far in the future when a farmer in Tanzania can pay for efficient LED lighting, a mobile phone and usage fees (which he uses to stay in touch with market conditions for his produce, including hedging commodity and weather risk and as a payments platform) all by selling his carbon emissions allowance to the market. Of course, we are a bit away from having a workable “retail” CER market, but if you ask me this is exactly the sort of thing the World Bank should be working on in cooperation with entrepreneurs in developing markets.
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