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

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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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27 thoughts on “Grid Capacity For Electric Vehicles Is Actually Not A Problem, Studies Find

  • Great Article!

  • Thanks for sharing this.

    I’ve been trying to argue every point in this report to the naysayers for years. They think electricity consumption will explode and cause all kinds of problems. And when they hear a Tesla Supercharger is 120 kW they totally freak out.

    Simple calculation. American cars travel 3000 billion miles a year. At 3 miles per kWh (most EV’s consume less), that equates to roughly 1000 TWh of electricity. Annual US energy consumption is 4100 TWh. So an overnight switch of all cars to electric drive would increase US electricity consumption by 24%.

    But there won’t be an overnight switch. It will take at least 2 decades, so enough time to adjust.

    • Assuming your numbers are correct, that is not a 24% peak increase. EVs can charge off peak. So would not require additional generation capacity.

      • Indeed. Although not to forget the fact that some local grid transformers might not be designed to handle the load of an entire neighbourhood charging their cars at night. But this is not a supply/demand issue, more a local grid constraint that operators handle on an almost daily basis.

        Peak time charging might be advantageous on sunny days in Germany. 🙂

    • And I’ll add my usual wind turbine bit.

      Right now late night electricity doesn’t have much value. Demand is low and thermal plants can’t or don’t want to shut down due to long start up times. The wind typically blows harder at night.

      All that adds up to low wholesale costs and little to no profit.

      Bring EVs on line and charge them when demand slows. That will create a market for wind and the extra profit will bring more investment. More investment means that more turbines will be installed and we’ll both generate the electricity we need to charge EVs, we’ll also have more low cost wind electricity during the day to lower the cost of grid power.

      • You might like this thought experiment that I invented.

        If you line the central reservation of motorways with modern 3 GW wind turbines, about 500 m apart, those would generate enough energy to power the cars using that motorway. Of course there is a large difference between quiet 2 lane motorways and busy roads of 4 or 5 or even more lanes. My calculation is based upon a mix of motorways and average usage. My country has one of the highest used motorway networks in the world, so you might need even less wind turbines in other countries.

        I always found that an interesting visualisation of the energy consumption of EV’s. And it is a lot less than most people think.

        • I like it.

          Here’s something I worked up a few months back…

          Land Required for Wind Turbines to Charge All US Cars

          Average miles driven per US car in 2010 was 13,476.

          EVs use roughly 0.3 kWh of electricity per mile.

          That’s 4,043 kWh needed per year to drive 13,476 miles.

          That works out to 11 kWh per day.

          The DOE estimates that, in 2007, the number of US cars on the road was 254,400,000.

          If all our cars were EVs, we would need to generate 2,798,400,000 kWh per day. Rounding up, let’s make that 2,798,500 MWh per day.

          The average size of a wind turbine in the US has a power capacity of 3 MW. Using the average size, a wind turbine will produce 30.1 MWh per day (3 MW x 24 hours x 43% capacity).

          To power 25.4 million EVs, we would need 92,973 3MW turbines.

          At 0.25 acres per turbine, the total land required would be 23,243 acres.
          For some perspective, the island of Manhattan contains 15,168 acres, Disney World covers 30,500 acres and Washington, D.C. covers 43,712 acres.

          Add in some losses for transmission and battery charging and the point is that we could get all the electricity needed to charge every car and light truck in the US with two Manhattans, one Disney World or less than one Washington, D. C.

          • Cool calculations. I think you underestimated using the 0.25 acres per turbine. I think its probably closer to an acre ~40ksq feet. Or it actually could be a hector (100Mx100M). Anyone have any thoughts on the density of tubines???
            (PS, Interesting to see the Disney World is almost the size of Washington DC;-)

          • People (including some top level folks) all over the web are using a quarter acre. I’ve forgotten the original source.

            Google “wind turbines quarter acre”.

          • In the interest of science, here’s another one.

            An average offshore turbine will generate 1500 kWh per m2 of swept area per year. The average EV uses 4000 kWh. A tiny 2 m diameter offshore turbine would generate more than enough for that EV.

            (Of course, smaller turbines are not as efficient as large ones, but it is about the visualising and in thought experiments, everything is allowed).

          • “(Of course, smaller turbines are not as efficient as large ones, but it is about the visualising and in thought experiments, everything is allowed)”

            Then a tiny portion of the swept area of todays turbines would be needed for each EV. Also, keep in mind Europe is working on refining 6.5 to 7MW turbines, with Vestas even reworking it’s largest to move up from 7MW to 8MW…wow!

          • Ummm, no. Consider this, pipelines for transporting oil require electricity. Refineries for converting oil into gas and diesel require billions of kWh of electricity a year. In California the biggest industrial use of electricity is moving water from wet places to arid places where it is used, like oil refineries. Deploying EV’s reduces these needs, shrinking the gap between current levels of demand and future electricity demand. Perhaps counter-intuitively, with each added EV.

            As gasoline refining and distribution kWh needs for electricity are reduced by EV deployment, the demand reduction is literally a net kWh subtraction from the new electricity needs created by EVs, shrinking the gap even further.

            Oil refineries are the second largest users of electricity in California. Conversely wind turbines, where developed, save water by the gallon. Measured in the billions. Replacing refineries with wind turbines simultaneously saves and produces electricity!

            Every gallon of gas used by drivers is pumped electrically from a large tank into customers gas tanks. This adds to the current transport infrastructure system’s use of billions of kWh’s to get gasoline and oil (diesel) to cars. To fully power a nationwide fleet of EV’s, wind turbines would only need to bridge that narrowing kWh gap.

            In California, over 34% of EV drivers deploy solar panels. Wind turbines in that case, would only need to supplement what solar plus gasoline distribution/refining needs are not covering, to completely bridge the future demand gap.

            At the point where many solar panels and EV’s are co-located behind the meter, the households EV load is eliminated. And regarding that remaining kWh gap, it is therefore conceivable that fewer net kWh’s (before the meter), would be required for an electrified transport system, than a gasoline powered one. Leaving a Disney World of wind turbine’s to power the rest of the country’s needs.

            (75% of the gas that reaches a car engine is wasted as heat – 90% of electricity that reaches an electric motor is used to turn the wheels)

          • Lots of good points, but most of the electricity used by CA refineries is generated inside the refinery.

            Didn’t know about the high use of water in oil refineries. I’m seeing 375 gallons per 40 gallon barrel of oil. That sound right?

          • Agreed. Oil and gas stocks provide most of the energy, but do not completely eliminate the electricity demands. Distributing a 134 billion gallons of gas requires a few electrons as well. Diesel and motor oil required for cars is also reduced by EV adoption. EVs don’t produce byproducts that spoil engine oil, and have no engine, or need for diesel fuel! Thanks for the reply.

            Where are the gallons of water use from, been a few years since I saw a cite for water use, can’t remember where?

  • Buried in the report was a beautiful ”Throw-away line” which can be further boiled down to – – “thats what they said about Air Conditioners !”

  • I’m not a fan of the sharing tool. I want to add my comments before posting to LinkedIn. Can it be tweaked to support adding comments?

  • Does anyone know if current technology would allow EVs to provide some of their own power through roof panel solar cells.

    • Lots of stories available with “solar car” search from CleanTechnia main page. Despite what we see from solar car competitions – which use very expensive NASA grade solar panels – the argument is there’s not enough room on a car roof to come even close to fully powering it with commercial grade panels. Many people are certainly figuring out they can easily charge their EVs from roof top solar arrays where the optimal sun orientation is constant and the risk of vandalism almost non-existent.

      In the niche market of pedal-electric hybrids there’s the ELF which has a small solar panel that will fill the battery with 8hrs sun for a trip of 20 miles including pedal assist.

      • thanks

  • Perhaps if we set the politicians loose on this they can create a problem so they can tax us to solve it, and then never solve it.

  • Considering that you are positing “without updgrades”, my electric utility, and many others, asked us to reduce electrical consumption due to heavy load during the recent cold spell for several days. How do you think these grids could take more cars (millions as you and Navigant suggest) being charged from 7pm to 7am during the winter without upgrades? Batteries are irrellevent to the net load required over the coarse of days & transformers are just a link of the chain.
    Is millions= 2,000,000 spread around the country? Maybe minimal impact to grids in that case. If you think grids can handle a large percentage of the 250,000,000 cars on US roads without major upgrades you and Navigant need to recheck your figures.

    • I’m wondering if they needed reductions around the clock or only during daytime peak hours.

      • When the plug-in car count in my area (Central Tn) goes from 2,000 to 200,000, day or night isn’t gonna help any. 10kish more cars will be charging at any given time than there are now. (In the winter it was probably at night only, but I’m guessing) I’m not a pessimist who doesn’t believe in solutions, but don’t tell me the grid can handle a large portion of 250,000,000 cars being electric without upgrades. If their term “millions” is 2 million, maybe, but then this article doesn’t mean much.

        • A NREL study a few months back found that the US grid could charge 70% of all cars were all to turn into EVs overnight. Earlier they had found that there was charging for a bit over 80%, when they included transmission that dropped to about 70%.

          That’s not to say 70% in all places. Some places like the windy plains might be 100%. Other places are likely on the low side.

          TVA is starting to move Oklahoma wind eastward. There’s lots of great nighttime wind on the other side of the river that would love more market.

        • Matt another thing to keep in mind is that actual electrical usage can fall. Over the last 4 or 5 years I’ve been replacing my in efficient appliances including the air conditioner, insulation, new duct work. My electrical consumption has fallen from 3MWh a month to 1.5MWh, or another way of putting it is my bill has fallen from 300 dollars a month to 150 dollars a month.

        • Matt, also remember that every time a new wind turbine is connected to the grid it basically means more power to charge EVs.

          In general the grid needs no more late night generation. Late night wholesale electricity prices are low because the market is limited. In many cases that wind generation during late night hours is surplus and that’s when EVs will get charged.

          Wind farms have a big head start on EVs and will likely stay well in front.

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