Getting Paid to Plug In May Drive Future Buyers to Electric Cars

PHOTO CREDIT: SUNPLUGGERS.COM
A plug-in version of the Toyota Prius and its charging station.

By Michael Balchunas

Published Feb. 20, 2010

The possibility that owners of plug-in vehicles may be paid to dispatch electricity into the grid has drawn a flurry of attention following a presentation in San Diego at the annual meeting of the American Association for the Advancement of Science.

While many prospective owners are focusing on issues related to charging plug-ins, researchers have also been studying how electric vehicles could be used as load-leveling appliances for the electricity system and as storage devices for power generated by solar photovoltaic systems and wind turbines.

The University of Delaware's Center for Energy and Environmental Policy and a group called the Mid-Atlantic Grid Interactive Cars Consortium, or MAGICC, have been the leaders in promoting the potential for vehicle-to-grid technology, commonly called V2G. Their presentation in San Diego last week has perked up interest in plug-ins, especially with some reports suggesting that electric-vehicle owners might be paid as much as $300 a month for allowing utilities to draw from their cars' batteries.

PHOTO CREDIT: SUNPLUGGERS.COM
A Prius charging station.

Although the concept is very promising, it may still be a while before that happens, and such a lucrative rate may be far too optimistic.

One requirement for such a plan is that a large number of plug-in vehicles be available to draw from. With more vehicles contributing power at certain times, less electricity would be needed from each, which could be a self-limiting factor in how much owners might be paid for allowing their cars to serve as standby power sources.

A second requirement is that systems must be enabled to allow bidirectional electricity flow and electronic communication between a car's electrical storage components and the utility, which will necessitate digital meters and other specialized equipment.

A third element is that car batteries will have to be able to both receive and dispatch power without leaving owners powerless when they need to go somewhere, and without significantly shortening a battery pack's useful life.

As the consortium says on its website, "The key to realizing economic value from V2G is to have sufficient vehicles connected and aggregated to satisfy the power requests of the grid, communicated to vehicles via a real-time signal, while at the same time not compromising the functionality and availability of the individual vehicle to its owner."

In a staff report published last year titled "Light-Duty Vehicle Electrification in California: Potential Barriers and Opportunities," the California Public Utilities Commission said that wide use of V2G technology "will require PEV [Plug-in Electric Vehicle] market penetration that is sufficiently scaled to allow stabilization of centralized renewable-energy resource plants, as well as a number of technological advances and grid infrastructure upgrades" such as bidirectional chargers and meters, along with "battery technology (that) would permit frequent charging and discharging of the battery by the utility without unacceptable adverse battery life impacts."

PHOTO CREDIT: SUNPLUGGERS.COM
A cutaway of the Chevrolet Volt.

The idea of using electric vehicles to make the grid more efficient has been under serious academic and governmental study for at least several years, and projects are now getting under way in the United States and other countries to examine not just V2G technologies, but also the use of batteries to store solar electricity, a third component of the V2G equation.

In January, the U.S. solar company Suniva announced an agreement with GS Battery USA to develop solar-powered energy storage systems. GS Battery is a subsidiary of GS Yuasa Group of Japan, another country where solar-to-battery-to-grid studies are under way.

The collaboration between Suniva and GS Battery is to begin with a system using a 30-kilowatt array of Suniva’s solar modules and GSB’s battery technology at GS Battery’s headquarters in Roswell, Ga.

 “Solar system owners that are able to store their energy output are also able to take advantage of many new economic opportunities,” said Yasuyuki Nakamura, President of GS Battery, in a news release. “Our state-of- the art approach allows customers to achieve better returns on investment with a more flexible and profitable solar energy supply. We are excited about the value of utilizing Suniva’s high-powered modules with our battery technology."

The economic advantages of V2G technology require a large fleet of electrified vehicles to draw from. That could take many years, but if plug-in vehicles prove popular, widespread adoption could occur sooner.

In California, a little-known state law passed last year requires the Public Utilities Commission to "evaluate policies to develop infrastructure sufficient to overcome any barriers to the widespread deployment and use of plug-in hybrid and electric vehicles," which the law's author envisioned as numbering in the millions.

Although California is expected to dominate the market for plug-in vehicles, as it already does for hybrid cars such as the Toyota Prius, Delaware has gone further than any other state in preparing for consumers to start using V2G systems.

In 2009, the state enacted a law to require that owners of electrified vehicles be compensated for contributing power to the grid at the same rate they pay to charge a vehicle battery. This is only a net neutral proposition for a plug-in's owner.

PHOTO CREDIT: SUNPLUGGERS.COM

However, the arrival of digital electric meters is likely to be followed in short order by the establishment of time-of-use electricity rates for consumers. They are already offered as an option in some utility districts. Time-of-use rates can be advantageous to solar owners, allowing them to, in effect, sell electricity to the grid at high rates during peak times and buy it at lower rates during off-peak periods.

Although many future owners' electrified vehicles would not be at home in the daytime, as portable energy-storage appliances they would be identifiable to a utility no matter where they were plugged in, whether at home, at work or at a movie theater. The utility's computer system would know when it was drawing power from, or putting it into, your particular vehicle.

How might a discharge scenario work? The owner of a plug-in car with 100 miles of electric range and a 15-mile drive to work might arrive there with about 85 miles of range remaining, while facing only a 15-mile drive home. The owner, having plugged in the vehicle at work, could then tap a few computer or cellphone keys to allow the utility to draw down the battery during the afternoon peak-load period but leave at least 20 or 25 miles of range with which to drive home.

This owner could sell electricity at a high price and buy later at home at a lower price. Meanwhile, the owner's solar array also could have been selling into the grid at peak prices. Ideally, day after day, the owner could carry low-priced electricity to work, sell it at a much higher price, then return home for more.

The technology to accomplish this scenario is not yet fully available; the main issues at present are battery life cycles and costs. A more likely approach in the near term is very small, occasional discharges from a vehicle to the grid. Considerable sums are being devoted now to research on improved battery packs.

The three key elements combined — renewable-electricity generation, battery storage using electrified vehicles, and the dispatching of power from a car into the grid  — have clear potential to help make the electricity grid more efficient, which is why the idea is under increasingly intensive study and discussion.

"This technology improves the electric system by providing balancing power via storage that would otherwise require burning fossil fuels to produce," said Willett Kempton, a University of Delaware professor who has been heavily involved in V2G research, at a bill-signing commemoration for the new Delaware law.