Wednesday, January 02, 2008

Pluggable Hybrids: The Need for More Electric Power Plants: Stop the Denial

Electric vehicles are a great idea for shifting much of the energy burden of transportation from oil to electricity. But we need to make sure we can make enough electricity to re-charge the large fleet of EV's that are required to make a difference.
Based on the default assumptions on the spreadsheet - 15 million electric vehicle commuters, a 40 mile commute, and 4.0 miles per kilowatt-hour - it would take 150 gigawatt-hours of electricity to charge into such a fleet of battery-powered cars when they are plugged in every night.

Given these are off-peak hours, and given a 10 hour average recharge cycle, the electric power grid would have to deliver 15 gigawatts of additional power all night in order to recharge this quantity of cars. Input your own assumptions!

In California, for example, where during peak demand the power grid can deliver over 50 gigawatts, this is probably barely feasible. But where will the additional electricity come from? Even assuming massive grid-scale storage capacity, you only get about 1.5 gigawatt-hours per day from a one square mile solar thermal plant - you would need to build 100 of these. A nuclear power station can easily output 1.0 gigawatts, and since they run continuously, that would add 24 gigawatt-hours per day - you would need to build about six of them. But what if decentralized sources of electricity were used to power electric cars?

Ecoworld has been kind enough to provide two online interactive spreadsheets to allow any reader to experiment with the numbers:

Gigawatts per E-Commuters

Photovoltaics per Electric Car

Ecoworld promotes the "series hybrid" which uses a small clean diesel engine running at constant rpm to an electric generator, which charges the batteries that power the electric motor drive.

Diesel can become a renewable fuel within the foreseeable future. So until safe, clean nuclear energy capacity is built to support an EV transportation infrastructure, we are going to have to make do with hybrids.

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