Electric vehicles are closer than ever to becoming a large-scale reality. Chevrolet’s much-hyped Volt is still on schedule for a 2010 introduction, despite the manufacturer’s financial woes. Toyota may be releasing its own plug-in hybrid (PHEV) to fleet customers later this year. With production getting in gear, attention is turning to another important question: how these new vehicles will stay charged.
The challenges involved in keeping a nationwide market of electric vehicles charged have not gotten a lot of press attention. But with some predicting rapid growth—President Obama wants to see 1 million hybrids on the road by 2015—utilities, manufacturers and industry groups are studying what large numbers of electric vehicles could mean for utilities’ transmission and distribution systems.
Getting power to the people
Generating capacity does not appear to be an issue. Because utilities anticipate most cars will be charged at night when demand is relatively low, it is expected that current capacity will be adequate to supply this new load. Utilities say transmission capacity also is adequate to meet anticipated demand. Instead, experts are focusing on technologies involved in getting electricity from the pole into car batteries.
“The existing transmission is all set,” said Ted Bohn, principal electrical engineer with the Argonne (Ill.) National Laboratory, the U.S. Department of Energy’s lead national laboratory for many aspects of PHEV development. “The distribution side is the question.”
For example, researchers identified pole-mounted transformers as one potential hotspot in the vehicle-charging process. These units typically get a chance to cool down overnight as demand drops off. But, Bohn said, if large numbers of PHEVs start charging when their owners go to bed, it could overheat transformers.
“The utilities now say the extra load is about equal to a plasma TV, but a lot of people turn off that plasma TV at 10 p.m.,” Bohn said. “Imagine a world where everyone is plugging in at 10 p.m.”
But utility-side researchers say power marketers are aware of potential problems and are incorporating electric vehicles into their overall load planning.
“Several utilities across the country are working to analyze their individual circuits all the way down to the individual customer level,” said Sunil Chhaya, senior manager of PHEV Development Programs at the Electric Power Research Institute, a utility-funded research group. “This will help them identify the pinch points in their systems, such as transformer and feeder capacity, to ensure that enhancements are made in a timely manner.”
Another question is where exactly people will be plugging in their vehicles. Using a standard 15-amp outlet, an owner could expect a full charge to take 12–18 hours, Bohn said. However, the Society of Automotive Engineers is now working on a new standard for devices that could deliver an 80-amp charge and a much shorter charge time. These appliances could cost as much as $2,000 each, he said, but the added convenience could make the investment worthwhile.
Public charging facilities also are a part of utility plans. These may be owned by utilities or by private companies, but either way, new standards are required to ensure both safety and performance.
“One critical element here is to ensure that the interface between the car and the off-board electric apparatus is standardized,” Chhaya said.
The charging process is one of several Rocky Mountain Institute (RMI) is investigating in its “Smart Garage” initiative. The Snowmass, Colo.-based energy-research group has brought together representatives from utilities, automotive manufacturers, equipment makers and others to explore current barriers to—and opportunities for—successful and widespread PHEV adoption. The group is optimistic current efforts will succeed where previous efforts, notably GM’s EV1 model, failed.
“They feel the technology is stronger. You’re not stuck in an electric car that could just run out. That was the problem the last time around,” said Laura Schewel, RMI’s program manager for vehicle electrification. “Especially with the amount of subsidies, we’re at least going to get hundreds of thousands of vehicles, whereas in the 1990s, it was shut down at 10,000.”
Electrical contractors could be prime beneficiaries, should RMI’s enthusiasm hold true, Schewel said. All those new charging appliances will need to be installed, and service may need to be upgraded to allow for a 220-volt connection. And demand for public charging stations also could be high, once standards are in place, to allow drivers to power up when they are away from home. She urges contractors to begin getting familiar with training and equipment requirements now, so they will be ready for new work once electric-powered rubber hits the road.
“A lot of utilities are taking action,” Schewel said. “But rate cases take a while, and infrastructure takes a while. So we need to get started.”
ROSS is a freelance writer located in Brewster, Mass. He can be reached at firstname.lastname@example.org.