Electric cars lessen dependence on fossil fuels, but what effect are they having on power consumption?

The concern often comes up that large numbers of electric cars will increase the demand for electricity and overwhelm power grids--despite studies to the contrary.

Now we have data: Electricity usage doesn't seem to be affected, at least thus far.

Representatives from Pacific Gas & Electric (PG&E)--which operates in California, an electric-car haven--told Midwest Energy News that electric cars have had almost no impact on the grid so far.

PG&E conducts a grid service check every time a customer purchases a plug-in car, to make sure there is enough electricity available to charge it.

Here's the key statistic: Out of roughly 10,000 service checks, only 12 neighborhood grids have had to be upgraded.

2011 Chevrolet Volt plugged into Coulomb Technologies 240V wall charging unit

2011 Chevrolet Volt plugged into Coulomb Technologies 240V wall charging unit

A report by another utility company--Southern California Edison--found that less than 1 percent of transformer upgrades were directly attributable to electric cars.

For now, it seems grids can handle electric cars just fine. There simply aren't enough electric cars plugging into the grid to have a noticeable effect.

It takes about as much power to recharge an electric car as it does to run four plasma televisions. Plasma TV's haven't caused much concern about grid failure.

However, utility companies have expressed some concern over clusters of cars in specific neighborhoods causing localized problems.

These "Prius clusters" may necessitate upgrades to local grid infrastructure, but that falls far short of an all-out grid overload. And 12 out of 10,000 local grid updates seems eminently manageable.

Utility companies can also anticipate demand by asking electric-car buyers to raise their hands, lessening the possibility of a surprise spike in electricity consumption.

And according to a landmark 2007 study jointly issued by the Electric Power Research Institute (EPRI) and the Natural Resources Defense Council (NRDC), even much higher rates of plug-in penetration won't stress the grid--assuming the bulk of recharging is done overnight.

Rest easy, America.

[hat tip: John C. Briggs]


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