New study: clusters of EV owners threaten to overload local electricity infrastructure

2015 Kia Soul EV

The growing energy demand created by EV charging could threaten the stability of electrical grids unless utilities take a proactive approach to planning their future networks, according to a joint study from management consulting firm L.E.K. Consulting and Australia-based charging infrastructure company Tritium.

Preparing the Grid for the Uptake of Electric Vehicles” highlights a clustering effect in which a higher proportion of EV ownership in certain locations could overload local electricity infrastructure, particularly the feeder lines into a street or other location.

“Utilities need to be proactive in planning for a future scenario of significant EV adoption, especially in a world where spending capex on additional infrastructure at the cost of the consumer is no longer a palatable response,” said Natasha Santha, Principal at L.E.K. Consulting. “The real challenge for utilities is managing peak demand increase and the greater unpredictability that comes with greater EV adoption. EV charging has an element of randomness that needs to be managed; this can stress local infrastructure and heighten the need for increased network investment.”

The study outlines five measures utilities should consider to maintain the pace of EV adoption while keeping grids stable:

  1. Create demand response programs such as time-of-use EV tariffs
  2. Use managed charging software that schedules home charging throughout the night, averting the risk of EV owners all plugging in at once during evening peak demand
  3. Provide clear, detailed information to businesses and entrepreneurs looking to install public charging infrastructure
  4. Assess adjacent opportunities such as stationary battery storage that can reduce grid augmentation costs and enable charger deployment in areas of the network that would otherwise be prohibitive
  5. Work with charging manufacturers to stay at the forefront of technology


Source: Tritium

  • jstack6

    Don’t worry too much. The UCS Union Of Concerned Citizens already did some studies. They found that over 80% charge Off Peak at night while they sleep. It actually helps the GRID by using excess energy when transmission lines are not at their Peaks. It’s good for EVeryone.

  • All-Purpose Guru

    This is also one of the reasons for V2G technology. By being able to skim short-term power out of other vehicles it enlarges the pool of electric vehicles that can be supported by the infrastructure.

    Actual charging demands aren’t too severe, and most of the infrastructure can handle it. What the utilities worry about is everyone plugging their electric cars in at 5:30pm during a heat wave when everyone’s A/C is running at full blast. This is a recipe for sagging power grids that V2G can help to prop up until the load normalizes.

    • earl colby pottinger

      And why would people even do that when the cheap rate are at midnight? Just because you plug in the car when you get home does not mean it starts charging then, most EVs have timers you set to charge when the power rate are at their lowest.

      • All-Purpose Guru

        First of all, not everybody charges at midnight, not everybody even HAS their lowest rates at midnight. (Mine start at 8pm, for example.)

        Also, you still plug the car in when you get home even though a timer will turn on charging later– this is how MY electric car (Honda Fit EV) works– but the utility can still draw power from the car regardless of the state of the charge timer. Have I also mentioned that when they draw from your car your meter spins backwards so you get credit for the power draw? This is even better if they draw during high-cost times because the credit is at the higher rate.

        Source: worked on a team to design and manufacture a V2G-capable hybrid truck.

        • earl colby pottinger

          You are right about when charging time will differ. Here I check at it is at 11 PM not midnight. The mid-rate starts at 7 PM.

  • mipak

    Total BS. In many cases in the future those same cars will provide energy to the grid as needed by home inverters tying their cars into the grid.

    • All-Purpose Guru

      That’s what I listed in my comment. The technology is called “V2G” or “Vehicle to Grid” and it allows the utilities to use already-plugged-in vehicles as “reservoirs” of power on a temporary basis to prevent voltage sagging.

      Just a tiny correction, though– the inverter is usually located in the vehicle, not the home, but that’s just a nitpick 😉

  • earl colby pottinger

    BullShit. If true then the same grid would fail at the end of the work day as multiple people turn on their stoves, microwaves, lights, washing machine/dryers, vacuums … etc

    • All-Purpose Guru

      Nope. The initial sag comes when everyone comes home at the same time– usually around 5:30-6:30 pm. Demand then tends to drop off throughout the evening after that point. Nobody turns on their stoves/microwaves/lights/laundry equipment all at the same time, but hundreds of electric cars (which tend to draw huge current at the beginning of the charge cycle) all plugging in once they get home WILL.

      The issue is not overall demand. It’s the spikes when huge power surges occur, the infrastructure has to be able to handle the maximums.

      • joelado

        Like he said, BS. Schedules and commutes create a spread when people charge. Not everyone works 9 to 5. Charging at home takes hours and can be delayed, especially since there is a new 300 mile range paradigm just around the corner. Plus commuters only use their EVs for 32 miles a day on average so they are not pulling a great deal of electricity from the grid. The only problem is EVs pushing peak electric use to the point where utilities will have to possibly need to build new power plants. However, utilities can now purchase battery packs to produce more electricity off peak and use that stored electricity to meet a higher peak beyond the power plants ability. It means that utilities will need to adjust their infrastructure to meet the new need. Something they would have to do for other reason such as population growth, greater electric use do to climate change, etc. anyway. The electric utilities business is to sell us electricity for what we demand it for. Regulated utilities try to game the system to make money by not providing us what we demand and charging us for it.

        • All-Purpose Guru

          Like I said before, this isn’t about overall grid capacity– we can handle many more EVs than are currently in use.

          This is about weathering the spikes and preventing brownouts and infrastructure damage. Too much load within a short period of time causes the voltage to sag and even if the utility NEVER sees the load they have to plan capacity around the POSSIBILITY of the load occurring or significant damage to the grid can happen.

  • Gillacey

    This has already been addressed. Funnily enough, it was thought of at least 10 years ago, to my knowledge, and there are several studies, field trials and projects done or in process to make sure this isn’t a problem. The simplest is to overnight charge your EV from midnight, when demand falls.

  • Paul

    This article merely introduces the issue, and it is clear that while the writer is only partially familiar with grid versus EVs, we should thank him/ChargedEV for posting it. I have been working on this issue for some time, and was the Keynote at the SAE Shanghai event. My presentation is here: The audience was especially enamored with my assertion on Slide 18 regarding prior studies (purple box).

  • joelado

    I’m so impressed by the comments here. The knowledge that people have about EVs is so much more sophisticated and complete today compared to 10 years ago. Arguments like the ones above just doesn’t wash.

    All I can say is, this argument again? The overloading the grid argument was brought out during the time when big plasma TVs were popular. Energy sucking plasmas were no problem, but EVs that charged slowly at the time typically and mostly at off peak hours were going to make the wires overhead melt (exaggeration but). Total crap. We now have millions more EVs on the roads and nothing they said would happen has happened.

    These studies normally put out a supposition that EVs will be charging their entire battery at maximum watts on really hot days in tight concentrations that will overload the transformers. Hey, Captain Obvious, get larger transformers, problem solved. What the real complaint is that utilities don’t want to pay to improve the electric infrastructure to accommodate EVs even though they will be selling more electricity and therefore recovering the cost and then some by people having EVs.

    They should be welcoming the opportunity to sell more electricity because LED lights, more efficient appliances, better insulation of houses and solar panels will be taking away a good part of their ability to sell electricity. Utilities in California have asked for rate hikes based on these things being factores in their “viability.” In other words the efficiency measures that Californians have taken have reduced the demand for electricity so much that the electric companies are complaining that at current rates they won’t be able to sell enough electricity to survive. ?!? Then they complain about having to build out infrastructure to accommodate a device that will help them sell more electricity?!? The real profit model for controlled monopolies like electric utilities is to increase rates and not have to spend any money on improving their system.

    EVs tend to overwhelm self-generated energy systems such as roof mounted solar panels, and take back the gains from using more efficient appliance and better applied insulation. Utilities should welcome EVs since the future of efficiency is making major strides and the cost of personal solar and wind are dropping by a significant amount.