Skip to Main Content U.S. Department of Energy
Energy and Environment Directorate

Research Highlights

Grid Friendly™ Charger Controller a Smart Choice for Electric Vehicles

Smart car

L-R: Kim Chamberlin, Frank Tuffner, Krishnan Gowri, Michael Kintner-Meyer, Rick Pratt, Nathan Tenney, Mark Morgan, Jewel Adgerson.


As electric vehicles become more prevalent, charging them has potential to place additional strain on the power grid. Researchers at DOE's Pacific Northwest National Laboratory have developed a new technology that allows charging of electric vehicles in a way that is beneficial to both the vehicle owner and the power provider.

The Grid Friendly™ Charger Controller technology, developed at PNNL, works with the ebbs and flows of the power grid to charge electric vehicles in a way that minimizes stress on the grid. By charging the vehicle at off-peak times, such as in the middle of the night instead of right after work when electrical needs typically spike, pressure on the grid is reduced. Given that utilities in some areas are also charging less during off-peak hours, consumers can also save money by deferring the charging of their vehicles until these times.

Why it matters:

Power grids world-wide are becoming more stressed as populations grow and the demand for electricity rises. Additionally, as consumers are more aware of the need to reduce the use of fossil fuels and protect our delicate natural environment, electric cars are becoming more popular. If this growing segment remains unmanaged, traditional charging of these vehicles, where a vehicle owner plugs in for an immediate charge, has potential to put more strain on an increasingly taxed power grid.


The Grid Friendly™ Charger Controller has two basic functionalities. The first feature is optimal scheduling that determines when to turn on, and when to turn off the battery charging. In the optimal mode, the consumer determines when they need the battery to be fully charged. Once preferences are set, daily charging of the electric vehicle becomes automatic. Technology embedded in the controller system communicates with the residential charging station's smart electric meter to receive real-time electric pricing updates or rate schedules. The system then makes strategic decisions about when to charge and when not to charge to save money, thus allowing consumers to reach the sweet spot between cost savings and convenience. The consumer has always the final control of the charging process and the system also has a "charge now" override option.

The other feature is the Grid Friendly™ charging mode. While charging, the actual rate of charging is regulated based on the grid's needs. This feature will become even more significant as the grid is required to integrate more variable and intermittent renewable energy resources, such as wind and solar energy. The fluctuation induced by variable wind and solar power plants will be sensed and the vehicle will be charged in a way to even out the fluctuations.

When fully deployed, the Grid Friendly™ Charger Controller could be located in a home or public charging station. The communication to the vehicle is performed using emerging communications standards being developed by PNNL, along with other national laboratories and the automotive and utility industries. PNNL developed the first communication devices that tested the emerging communication standards between the vehicle and the charging station.

What's next:

The Grid Friendly™ Charger Controller for electric vehicles has been deployed in a smart charging station on PNNL's campus. The technology is being demonstrated with PNNL's PHEV Toyota Prius test vehicle.

PNNL's team also is working with the National Institute of Standards and Technology and the Society of Automotive Engineers to develop testing and verification methods for communication standards. This would allow for wider adoption of smart charging technologies and particularly, the marketability of the Grid Friendly™ Controller for use at public charging stations. Wide-spread, regulated use of this type of technology would enable the power grid to be more sustainable and support the variability of green energy because of its modulated charging method.

This technology is available for licensing, see PNNL's Available Technologies website.

Acknowledgements: This research was funded by the DOE's Office of Electricity Delivery and Energy Reliability, and the Office of Energy Efficiency and Renewable Energy's Office of Vehicle Technologies Programs.

Research team: The research team for this work includes: Michael Kintner-Meyer, Rick Pratt, Krishnan Gowri, Frank Tuffner, Paul Boyd, Nathan Tenney and Jewel Adgerson of Pacific Northwest National Laboratory.

Energy and Environment

Core Research Areas