Monday, February 11, 2008

Walking as an Energy Source

The push to get away from fossil fuels is something I'm sure all of the readers of this blog are familiar with. Two quick things along those lines while I get ready to head out of Evanston for the night.

First, this paper in Science which I'd like to claim that I found while perusing scientific journals at 7am with a big cup of coffee, but in reality I found on Ben's desk, which shows a prototype for a device which takes advantage of a normal human walking motion to generate electricity and their attempts at overcoming the burden of having to wear a big knee brace while you're walking. They employ a one-way clutch to gather energy only when the knee is straightening (not when it's flexing) so that power is generated when you step forward. I know nothing of the engineering here, but it seems like an interesting if unwieldy idea. They do a fair job of pointing out some applications for the technology, primarily power-generation in places on the earth that are not connected to a power supply and the use as a power-generating source for motorized prosthetic limbs, such that you'd use your healthy limb to help you move the prosthetic, which is kind of cool.

Second, an interesting discussion on the feasibility of biofuels on Talk of the Nation last week. I'm more familiar with cost-effectiveness arguments for and against the use of biofuels (it's not feasible to use corn as a source of ethanol in the US because of the way we grow and harvest corn and its poor return on investment, while Brazil derives a bunch of ethanol from sugar cane as a waste product, and so it's relatively cheap and easy for them to implement biofuels.) Their argument is more focused on carbon-release, and without getting into the whole global warming discussion, it's an interesting phenomenon to note that if we're going to grow crops like switchgrass (which is much more energy efficient than corn) to use as a fuel source, we'll end up either leveling forest to free up land to do so or using land which would otherwise be used for food, which forces the food-farmers to go and level forest, and so the end result is the same. I recommend listening to the bits on the use of algae and bacteria to produce fuel, but mostly because I've got a friend who's a synthetic chemist and has been, as far as I can recall, playing around with bacteria to get them to make things for him.

1 comment:

Ben said...

Reading this I pictured you having your coffee at 7 am while reading Science and it brought a smile to my face.
Now if it was 7 PM I would understand