by: Michael Hoexter

A quick post to call attention to two recent electron economy related news items:

1) You’ve probably read in your local paper, on the web or on TV about the MIT researchers that have figured out a way to light up an electric light bulb without plugging it in by beaming power to the light over a distance of 7 feet.


The researchers call the invention “WiTricity” after with the now familiar “Wifi” concept. The researchers have used the magnetic resonance of a copper loop embedded in the wall of the room to send the energy to the lightbulb. The researchers claim that the process is 40% efficient meaning that it is about half as efficient as rechargeable batteries and less than half as efficient than plugging into a wall socket.

As this is an early stage prototype, one can only imagine that future designs will substantially increase the amount of energy transfered to the object rather than dissipated in the process of sending it. Wireless transfer of energy is not unknown with focused microwave transmission but these are thought to be hazardous to human health. The claim is that magnetic resonance unlike intense microwave radiation, does not affect human health adversely. Witricity is a special case of magnetic induction similar to the process that is used to heat pots and pans on induction stovetops. The novelty of Witricity is the distance and relative efficiency of the transfer.

While we are not yet powering our cars using WiTricity and condemning the electric cord to the dustbin of history, the ease with which electric appliances and vehicles will be powered will increase in the future. We should not wait for these ultra-easy ways to transfer electric energy to develop electric transport and other applications, but developments such as this and quick charging batteries make objections to electric transport seem all the more antiquated.

2) PG&E, the farsighted electric utility in Northern California, has made a preliminary commitment to buy used hybrid and electric vehicle batteries once they are removed from use by the manufacturers. As a demonstration, they now have a battery from a wrecked Prius in the basement of their headquarters which is connected to the grid. While these batteries may no longer have the same capacity as they had when they were new, they will function as electric storage facilities to help respond to peak demand and eventually allow for the grid to use more variable power generation sources such as wind and sun. (I haven’t yet introduced stationary storage in my series but here is a preview)

In one step, PG&E has provided a possible answer to two different open issues related to renewable energy sources and to electric transport: storing and distributing electric power on demand AND how to reuse old batteries from the growing fleet of electric drive vehicles. An aftermarket for rechargeable batteries is thus formed: the replacement of their batteries for upgrades or repair becomes that much more economical. These are further signs of a virtuous circle linking renewable energy and electric transport.

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