
Move over, solar: The next big renewable energy source could be at our feet - Lind5
http://news.wisc.edu/move-over-solar-the-next-big-renewable-energy-source-could-be-at-our-feet/
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james-rms
This seems like a non-starter. A quick conservation of energy check:

Human beings put out around 75W of energy when they're not excercising. Most
of that is body heat. They also take around 10,000 steps a day, which
translates to around 85 mins walking per day. Even in the scenario where you
could capture 10% of that 75 human watts for those 85 minutes, that's only
enough energy to run a 15W LED bulb for 42 minutes.

Harvesting energy from cars is also a non-starter. Any energy you harvest
there is added as a load on the engine of the cars, which are all powered by
fossil fuels. It's a really inefficient way to turn a car engine into an
electric generator.

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theandrewbailey
> Harvesting energy from cars is also a non-starter. Any energy you harvest
> there is added as a load on the engine of the cars, which are all powered by
> fossil fuels. It's a really inefficient way to turn a car engine into an
> electric generator.

The vast majority of cars already have a small electrical generator installed.
Plugging things into a cigarette socket to access that electricity causes 0
extra load on the engine.

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cesarb
> The vast majority of cars already have a small electrical generator
> installed. Plugging things into a cigarette socket to access that
> electricity causes 0 extra load on the engine.

No. Your use of energy from the generator through the cigarette socket
manifests as a braking force in the generator. The more energy you use, the
more it brakes. The car's engine has to work harder to overcome that braking.

~~~
ericmo
What about regenerative braking?

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monitron
Of course if this makes flooring more compressible (how else would it work?)
we're just stealing bits of energy from the people walking on it. Then again,
many of us (myself included) eat too much and could use a little more energy
expenditure!

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JoeAltmaier
The least possible green energy source is people. The energy comes from food,
which has the largest carbon footprint of anything we consume (pretty much of
anything we make).

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mattnumbe
I don't understand why news about the alternative energy industry always makes
it sound like we will eventually move to one energy source. Using a combined
approach is the most obvious and probable outcome.

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ericmo
Even being pessimistic about solar power, it still has the greatest potential:
[http://energypost.eu/reality-check-renewable-energy-
potentia...](http://energypost.eu/reality-check-renewable-energy-potential/)

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mankash666
For a purportedly scientific article, there's no mention of the actual energy
generated (per square foot?) assuming a traffic rate typical of possible
install targets.

