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Rising volume of electric vehicles may outstrip existing power grid capacity

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The energy sector must change to meet a growing population’s evolving needs. However, as overall energy demand continues to increase, the concurrent growing use of electric vehicles (EVs) is likely to further strain existing power grids. Smart electrical grids are seen as one component of meeting that challenge.

Smart electrical grids allow cities to divert energy to places that need additional capacity or that lost power temporarily. As the technology evolves, energy consumption could be priced by consumption and capacity utilization. Thus, running appliances at low-demand hours could cost less than at high-demand hours. If renewable sources generate the power, then additional optimal hours for appliance use would be when the appliances can utilize the renewables’ capacity, such as daylight hours for solar power. This principle carries over into EV charging.

Smart charging for EVs is the next step toward developing a more stable electric grid and optimizing the demand for energy based on capacity and source. The idea has undergone some preliminary testing to gain consumer buy-in, since allowing utility companies to decide when vehicles get charged raises concerns. Some have worried about when charging could take place and whether the battery would be charged completely.

Electric utility companies across the United States already rolled out testing programs for smart charging, and some have started expanding them, as the companies have seen additional demand from customers. The testing has allowed utility companies to collect data at a small scale so they can better optimize their models for the best times to handle additional demand for electricity from EVs before rolling out full-scale plans.


Green Mountain Power based in Colchester, Vermont, introduced a program that gives Level-2 chargers to EV owners if they spent less than $60,000 on the vehicle. They are then enrolled in a monthly fee program to charge their vehicles. At $29.99 a month, households can charge as much as they want, as long as they allow the utility company to set the times and rate of charging. Households can also opt out of the program and pay a flat rate of 60 cents per kWh. Of those that received the free charger and enrolled in the program, only 1.1% subsequently opted out.

Xcel Energy partnered with Enel X in Minnesota to give away 100 Enel X smart chargers to households on a first-come, first-served basis. This allowed Xcel Energy to collect data, and households would save money. The price for charging varied by the utility’s available capacity and promoted charging at night to lower prices since energy demand is lower at that time.

Sonoma Clean Power (SCP) also partnered with eMotorWerks in the Sonoma, California, area, where eMotorWerks provided 1,000 free smart charging units to SCP’s customers and developed an incentive program allowing SCP to control when the vehicle gets charged when it is plugged in. JuiceNet, the rewards program, provided cash-back rewards for leaving the vehicle plugged in while home, allowing households to charge at the optimal times for SCP, such as when renewables are abundant or when energy demand is low and additional capacity is readily available.

Class 7 and 8 vehicles will further add to the electric grid strain. Their batteries are bigger and require more power to charge. Currently, many of these heavy trucks operate on diesel.


Distillate fuel oil in the transportation sector is primarily diesel, which medium to heavy trucks consume. According to the Environmental Protection Agency (EPA), these vehicles account for almost a quarter of emissions produced by the transportation sector.

Source: SONAR – Carbon Dioxide Emissions from Distillate Fuel Oil in the Transportation Sector

Distillate fuel oil carbon dioxide emissions (DMACE.USA) make up about 23% of the emissions produced by the transportation sector as a whole. These emissions are on the rise, which can be seen in the FreightWaves SONAR chart above. In efforts to mitigate emissions, truck manufacturers are developing electric trucks as an option for carriers.

Smart charging could help ease some of the capacity issues, but that would require updating much of the existing infrastructure. And even then, utilities may still have to build out more capacity. A single truck requires a lot of energy to charge. Just imagine a fleet.

David Thill, writer for Energy News Network, contributed to this article.