The commercial license agreement for a frequency-responsive technology that tells an electric vehicle’s (EV’s) battery charger when to start and stop charging based upon existing conditions on the electric grid has been reached between developer Pacific Northwest National Laboratory (PNNL) and AeroVironment Inc. The technology could boost widespread adoption of plug-in EVs and support the integration of variable renewable sources while alleviating concerns about grid stability.

PNNL, a Department of Energy (DOE) national laboratory that is operated by Battelle, and Monrovia, Calif.–based AeroVironment reached the agreement for the Grid Friendly EV Charger Controller technology last week.

AeroVironment is expected to use a portion of the licensed technology in a new prototype version of its Level II charging systems. The technology helps stabilize the grid by continuously monitoring the grid’s alternating current (AC) frequency and varying the vehicle charging rate in response. If an unexpected event on the grid causes a rapid drop in the AC frequency, the charging system will stop charging, providing a grid "shock absorber."

According to AeroVironment, such rapid frequency drops, while small in overall magnitude, "indicate that a fault condition has occurred somewhere on the grid and that there is an imbalance between load and electricity generation. By reducing load the system can be rebalanced."

One possible important application of the technology: If millions of plug-in vehicles using it are charging at any given time, it could help support the integration of variable renewable generation by controlling grid frequency, both PNNL and AeroVironment said.

A 2012 PNNL study found the U.S. existing power grid could meet the needs of about 70% of all U.S. light-duty vehicles if battery charging were managed to avoid new peaks in electricity demand. "Under normal conditions, this stabilizing technology will be particularly important as the power grid is expected to rely more and more on variable renewable resources such as wind and solar technologies," PNNL said.

AeroVironment Chief Technology Officer Alec Brooks of the company’s EES business called the technology a "triple-win." In a statement he said, "First, reducing the cost of integrating variable renewable generation reduces the electricity costs for all ratepayers. Second, plug-in cars can be powered by renewable generation that might not have been possible to add to the grid without the charging rate flexibility offered by vehicles and this technology."

"Third, the reduced cost of electricity to plug-in vehicle drivers will further improve on the cost advantage of driving on electricity as compared to gasoline."

Sources: POWERnews, PNNL, AeroVironment

Sonal Patel, Senior Writer (@POWERmagazine, @Sonalcpatel)

Note: This story was originally published on Wednesday, March 13, 2013.