Is Harvesting Energy from Passing Cars "Free"?
Whether it's delivering produce by barge, or turning waste food into electricity, UK supermarket chain Sainsbury's has certainly pushed the envelope when it comes to green initiatives. Their distribution center was even featured in our slideshow of urban wind turbines. As part of their latest effort - an innovative eco-store that also features solar power, rainwater harvesting and recycled construction waste - the chain is boasting that checkout tills will be "people powered". The only trouble is, the term "people powered" seems to mean running the tills on gasoline... Profiled in The Guardian, Sainsbury's new ecostore features "kintetic road plates" which harvest a small amount of energy as cars drive into the carpark, converting it into electricity that is then used to power the checkouts. The makers claim that the energy is essentially free. Here's more from The Guardian:
"Energy will be captured every time a vehicle drives over "kinetic road plates" in the car park and then channeled back into the store. The kinetic road plates are expected to produce 30 kWh of green energy every hour — more than enough energy to power the store's checkouts. The system, pioneered for Sainsbury's by Peter Hughes of Highway Energy Systems, does not affect the car or fuel efficiency, and drivers feel no disturbance as they drive over the plates.
Lloyd actually covered kinetic road plates a while back, and he was less convinced that there was any benefit at all. After all, in order to harvest energy, the device must be slowing the car down, thus increasing fuel consumption ever so slightly. But, as one commenter pointed out at the time - if the device is placed somewhere where folks are breaking anyway, then you are certainly capturing some free energy (except from hybrid vehicles which would have captured the energy themselves).
There's no information in The Guardian article on where the plates are placed, so it's hard to evaluate their "free energy" claims - but I'd be interested to hear readers' thoughts on the viability (or not) of this type of system. Who knows, it might spark the kind of monster debate that ensued from Michael's previous post on Further Thoughts on Turning Road Traffic Into Electricity.