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Published on February 3rd, 2014 | by Sandy Dechert

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Grid Capacity For Electric Vehicles Is Actually Not A Problem, Studies Find

February 3rd, 2014 by  


Somehow, Americans have trouble grasping the idea that our current utilities can support a high number of electric cars without building hundreds of new power plants. However, a new study from the global clean technology consultants at Navigant Research emphatically puts the notion of utility and grid insufficiency to rest.

In fact, Navigant says, the power grid we have right now can sustain millions of electric vehicles without anyone having to invest in new power generation.

Electric transmission stationGrid anxiety related to EVs, it turns out, is illogical. (Photo: facebook/photos.)

Utilities and automakers don’t fear higher EV load

Large power companies like Duke Energy, for example, are working with national organizations and large and small automotive manufacturers on how electric vehicles will interface safely and reliably with the current grid. Duke actually sees clear benefits to electric vehicles for these reasons:

  • They save customers money: “filling up” an electric vehicle is cheaper than fueling a traditional car.
  • The environment will benefit because widespread adoption of electric vehicles will cut harmful emissions.
  • The nation’s push for energy independence and local jobs markets will both benefit.

The company’s commitment is so deep that it is offering Level 2 charging stations to qualified EV customers.

Portland General Electric president Jim Piro has also said that despite the Portland metro area’s early adoption of greener vehicles, his utility has few concerns about adding cars to its grid.

Conversations with automakers bear out this conclusion as well. Said Ford’s Mike Tinskey in a late August news conference:

We’re not just throwing cars into the market.

With PGE, for example, Ford is working with cities, utilities, and consumers to make sure the grid is ready and buyers are educated.

Transformer issues expected to be minor

The local distribution transformer is the most vulnerable location to EV demand on the power grid, Navigant points out. “Residential customers are supplied electricity through a transformer that feeds a number of units. If all or many of the units supplied by a transformer require increased load for PEVs, the transformer may need to be upgraded to increase peak capacity and use.”

Every time a customer purchases an EV, say Pacific Gas and Electric representatives, who serve large EV populations, the company conducts a grid service check to ensure the local distribution transformer has enough power to charge it. Out of the 10,000 checks, the company has only had to upgrade 12 local grids. A recent report by Southern California Edison attributed less than 1% of transformer upgrades directly to plug-in vehicles. Green Car Reports says that local distribution transformer updates are a relatively low-cost fix.

Only one other potential issue has concerned utility officials.

“A neighborhood full of older homes with smaller circuit breakers, ‘and everybody charges at 8:01 p.m.,’ would strain the grid–and homeowners’–patience,” says PGE’s Piro, “but that’s just the kind of situation utilities and car makers are trying to head off with advanced technology and education.”

Demand-response programs (in which customers respond to incentive payments, high wholesale market prices, or glitches in overall system reliability by changing their normal consumption patterns) are part of these solutions. Additionally, since many areas with older housing stock are in city cores, recent trends toward restricting cars in these areas, enhancing public transportation, and creating viable pedestrian and two-wheeled routes can be expected to level off or lower excessive vehicular traffic there.

Why the myth of EVs causing grid failure flourishes

The Navigant study suggests that the misconception about electric vehicles having the potential to overwhelm the grid probably stems from a widespread misunderstanding of how little energy it takes to charge–and run–an electric car.

Plug-in electric vehicles “are far more efficient than petroleum-powered vehicles. With an average battery size of 40.1 kWh, battery electric vehicles have an average range of 124.2 miles. For plug-in hybrids, the figures are 11.7 kWh and 27.2 miles for all-electric driving. Using the same 12,000 miles per year metric, the average BEV consumes 3,869 kWh of electricity a year, and the average PHEV (utilizing all of its electric drive capacity every day), 4,271 kWh of electricity.”

If electric vehicles were as inefficient as internal combustion engines, they would more than double the average home’s energy requirements. They do not.

Other key findings

  • EV charging will only minimally influence peak electricity demand because “few PEVs are plugged in during these times, fewer still in areas where PEV owners are enrolled in time-of-use programs.”
  • Behavioral factors are also at work. A smaller-scale, performance-based study by the Pecan Street Research Institute of Texas (reported over ClimateWire on October 28), parallels Navigant’s conclusions. The Pecan Street study found that owners charge their EVs much less during hot summer afternoons than most behavioral models predicted.
  • Deployment of grid balancing programs that even up market demand and generation supply will also help. Some can figure large electricity customers’ flexible process storage into the real-time needs of the power system, and others allow two-way communication from residential meters to the utility.
  • So will changes in the utilities’ demand charge practices.

“When everyone got air conditioning, we served the load. You serve the load no matter what,” Mark Duvall, director of electric transportation at the Electric Power Research Institute, told E&E News.

“The net effect to utilities [of increased demand for EV power] should be new revenue streams with few costs,” Navigant concludes.

The real payoff will come with true vehicle-to-grid linkage. Advances like the CarWings system for Leafs and OnStar system for Volts will increase a driver’s ability to charge at cheaper, off-peak times. When telematic communications and V2G technologies become the norm, both utilities and consumers are likely to save money. Advances in renewables integration will help balance load on the grid, too. Says Duvall:

Can vehicles act as storage? Yes, they can.

Ultimately, the entire system might level off nicely by using EV batteries to store grid energy. For now, the bottom line of the Navigant study and other reports is that consumers should not really have to worry about grids becoming destabilized by increased EV charging–particularly since car manufacturers and electric utilities aren’t concerned about it.


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About the Author

covers environmental, health, renewable and conventional energy, and climate change news. She's currently on the climate beat for Important Media, having attended last year's COP20 in Lima Peru. Sandy has also worked for groundbreaking environmental consultants and a Fortune 100 health care firm. She writes for several weblogs and attributes her modest success to an "indelible habit of poking around to satisfy my own curiosity."



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