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City Grids May Not Be Ready for Electric Cars

The nation's grid is ready. Your neighborhood's power supply might be another story

February 15, 2012 RSS Feed Print

Buried beneath the defense reductions and tax increases in the president's new $3.8 trillion budget is another initiative getting less attention: increased incentives for electric car purchases. President Obama is proposing that the tax credit for an electric car purchase be raised from $7,500 to $10,000. That, along with fears of sky-high gas prices, could drive purchases up...but some city power grids may not be able to handle a new fleet of plug-in cars.

[Read: Could the U.S. economy ever look like Greece's?]

Depending on how you parse the figures, an electric vehicle's power usage can sound either negligible or massive. The all-electric Nissan Leaf, for example, has a 3.3 kW charger, roughly equal to the usage of a clothes dryer or two hair dryers. But added up, the amount of energy that car uses can be far greater. Running a clothes dryer all night, half the time it takes to fully charge a Leaf battery on a standard home outlet, could make for a substantial increase in a household's electric bill.

According to the EPA, a Leaf consumes around 340 watt hours per mile. Charge that car enough to drive 30 miles per day, and that's more than 306 kilowatt hours per month, nearly one third of the national average home energy usage of 958 kilowatt hours, according to the Department of Energy. The addition of three new Leafs with this driving pattern, then, would be the equivalent of adding another household onto an electrical grid.

Depending on the home, driver, and electric vehicle in question, the amount of energy consumed can be even greater. "One vehicle's demand can be anywhere up from three quarters of a house up to three houses," says Jay Tankersley of Project Get Ready, an initiative of the nonprofit Rocky Mountain Institute.

Many experts agree that, on a national level, the United States is ready for a vast expansion in electric cars. According to a 2008 Energy Department study, the effect of a vast expansion in electric vehicles could be minimal. Electric vehicles are expected to account for around one quarter of the market by 2030. If those vehicles are all charged after 10 p.m., when electricity demand is low, the nation would require no additional power generation. Then again, if all owners charged their cars at 5 p.m., up to 160 new large power plants would be necessary.

The nation as a whole might have the capacity, but on a neighborhood-by-neighborhood basis, the problem is more pronounced. "In most residential areas, an EV can easily be accepted into the charging infrastructure. [But] as soon as you start getting clustering of vehicles, they can't have too many of those in one area without some kind of a strategy for adapting to it," says Allan Schurr, vice president of strategy and development for energy and utilities at IBM.

As people of similar incomes, not to mention mindsets, can often group together in neighborhoods, electric vehicles can also tend to be purchased in geographic clusters. That effect, which some have called the "Prius cluster," is already a consideration for utility companies in California, as Business Insider reported last year.

Consider what happens in a typical city neighborhood on a hot August evening: one too many air conditioning units overloads the transformer and knocks out power. A few electric vehicle clusters could have the same effect. A substantial increase in electric vehicle sales, then, would produce fewer emissions, but also a few city blocks of angry neighbors.

So while electric vehicle buyers can see significant savings on gasoline—a gas-powered vehicle can be three to five times as expensive as an electric car, according to the Energy Department—they could also, depending on their city's infrastructure, also suffer some inconveniences.

More than 2,400 public and private charging stations have popped up nationwide, according to the Energy Department, but home charging is still the top choice for EV owners. Around 80 percent of plug-in electric vehicle users charge at home, says Tankersley, meaning that residential areas bear the brunt of vehicles' electricity usage.

An earlier version of this article inaccurately described Project Get Ready. It is an initiative of the nonprofit Rocky Mountain Institute. The article also misspelled Allan Schurr's name.

Tags:
energy,
renewable energy,
cars

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This is the other dirty little secret about all electrics and plug-in electrics -- the our electric grid and electric generation capacity simply cannot support the energy demands even a 20% adoption rate would place on them. Most people are ignorant of the power requirements of personal transportation and the balancing act involved in electric power generation and distribution.

checker99 of OH 9:48AM January 09, 2013

A thousand Kilowatts has been anounced as the average for a family of three for many years, here in Florida that is $110 energy and fuel surcharge total monthly. The electric car uses 1/3 that much for total monthly fuel bill. that is $38 monthly. I drive only 35 miles four trips weekly that is 140 miles weekly or 560 miles monthly or at $3.619 per gallon for my monthly full usage the total is $72.38 (at 28 mpg) almost twice as much as the electric charge for 210 miles weekly in your example. Obvously I save with the electric car. but the best way to recharge is a solar PV panel which will pay itself off in less than five years .

Dennis Miles of FL 9:26PM February 22, 2012

Even if EV charging can be delayed until the demand of the household is down, the service transformer may still overheat, because it is generally designed to have a cool-down period in the wee hours. So, households with EV charging may need upgraded service transformers.

Venturajohn of CA 12:31PM February 22, 2012

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