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May 28, 2009

Will Plug-in Hybrids Cause Blackouts?

By Kennedy Maize

Plug-in hybrid cars could get a boost from new technology developed at the DOE’s Pacific Northwest National Laboratory (PNNL). But they could also add electric demand that could crash the U.S. transmission and distribution grid, according to the researchers.

PNNL engineers have come up with a way for owners of plug-in hybrid cars to recharge their batteries at times when electricity costs the least and demand is lowest, possibly preventing a grid collapse. It’s a high-tech timer (see figure).



Engineers at the Pacific Northwest National Energy Laboratory have designed a Smart Charge Controller that will charge your plug-in electric hybrid vehicle when the cost of purchased power is low. Courtesy: PNNL

Plug-in Vehicle Owners Can Set and Forget

Researchers at the Richland, Wash., lab have developed what they call the “Smart Charger Controller” to make sure consumers driving plug-in hybrid cars charge their vehicles’ batteries when systemwide electric demand is lowest. In an April 2009 press release, PNNL (operated by Battelle Memorial Institute of Columbus, Ohio, since 1965) said, “Electric vehicle owners can plug in their cars and forget about them, knowing they’ll get the cheapest electricity available and won’t crash the grid.”

According to PNNL, the controller allows owners to “program the controller to charge at a specific time of day or night or at a set price point. The controller uses a low-range wireless technology to communicate with the power grid and determine the best and cheapest time to recharge vehicles.” This, of course, also assumes a smart grid that can communicate with the controller—something that is still largely in the minds of grid engineers, not hanging from transmission and distribution poles today.

The ability of the smart car battery charger to react to load demands, says PNNL, “could serve as a shock absorber for the grid. The technology would relieve load instantly and give grid operators time to bring new power generation sources on line to stabilize the grid—a process that usually takes several minutes.” The controller, says the lab, can sense stress conditions on the grid and temporarily stop charging when instabilities threaten to bring it down.

PNNL created a short video that demonstrates charging technology aimed at maximizing the value of a plug-in hybrid car by ensuring that it gets charged from the electric grid at times when demand and prices are low.