Looking for a device that automatically charges your electric car during the time of day when power is cheap? The Pacific Northwest National Laboratory has put taxpayers’ money to good use by developing such a device, the "smart charger controller."

The lab, part of the national lab system run by the U.S. Department of Energy, announced its invention Thursday and said the device could save consumers $100 to $150 per year. Major automakers such as Toyota, Nissan and General Motors plan to start selling all-electric or plug-in hybrid electric cars over the next two years. Many companies have been working on developing technologies that would speed up the charging time and make it easier for consumers to charge their cars while they are out and about.

If electric cars become popular, then there will be a huge demand for electricity. Utilities are already trying to figure out how to handle this demand, particularly during peak hours. They, and other electric-car promoters, have surmised that people will do most of the charging at home at night, when power demand is lower and electricity is priced more cheaply. But consumers don't always behave as expected. To avoid using gasoline to run the plug-in hybrids when battery packs are depleted, consumers will have to be able to charge their cars during the day.

The lab said its smart charging controller would communicate with the power grid to get pricing information and allow consumers to program the time and price point for charging their cars. The controller would interrupt charging if the grid is over-tapped and grid operators need time to bring new power sources online to balance the load. The device can be installed in a power cord, charging station or the car itself.

So, this is not just a fancy science project for the Richland, Wash.-based lab. It’s looking for businesses deals to commercialize the technology.