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Additional energy needed for 100% electric vehicle fleet
To fully switch to a 100% electric vehicle (EV) scenario, the current electric grid will need to undergo significant upgrades and modifications. The question is, how much additional capacity will be needed for a fully electrified light-duty vehicle (LDV) fleet in the U.S.? To answer this, we will compare it to historic grid expansion to gauge the level of disruption this conversion will cause.
Additional Energy Needed!
We plan to transition to using only electric vehicles by 2040 in an aggressive but realistic manner. To determine the amount of energy needed to power these vehicles, we will multiply the total miles traveled by the energy used per mile. The National Transportation Statistics report by the US Department of Transportation, Bureau of Transportation Statistics provides reliable data for miles traveled by different types of vehicles. For this article, we will focus on Light Duty Vehicles which includes cars and trucks, and use the latest data from 2021.
Electric vehicles come in different sizes and designs, each with varying levels of efficiency. We have chosen 360 Wh/mile as the average energy consumption for our Tesla Model Y, which has traveled over 47,000 miles between September 2020 and April 2023. This vehicle is mid-sized and falls between a compact car and a full-size pickup. We drive it for 18,000 miles annually, including three winters and two summers in Minnesota, with frequent high-speed freeway travel. The energy used per mile includes all the energy required to move the vehicle, climate control, battery conditioning, and other energy-related tasks.
We will use current data to avoid making predictions about future electric vehicles and personal transportation trends. We will also factor in a charging efficiency value of 90%, which represents the difference between the energy put into the vehicle during charging and the energy used for driving. We will use this value to estimate grid demand or the energy required for charging. Finally, we will calculate the total additional grid capacity needed to support a 100% electric light-duty vehicle fleet in the US.
Total U.S. Energy Use with 100% Electric Light Duty Vehicles
| Total Light Duty Vehicle miles (millions) | 2,088,580 |
| Watt-hours per mile | 360 |
| Total Energy used per year (GWh) | 751,889 |
| Charging efficiency | 90% |
| Charging energy needed per year (GWh) | 835,432 |
It may seem like a large amount, but the replacement of crude oil mining, transportation, refinery operation, fuel distribution, and combustion in vehicles by 835,000 GWh is significant for operating today's internal combustion light-duty fleet. To understand the additional grid capacity needed, we will simulate 2040 demand by adding this amount to 2020 grid demand, calculate the percentage grid demand growth, and compare it to the historical growth in U.S. electricity demand over 20-year periods from 1920 to 2020, which covers over 99% of the U.S. grid build out to date.
US grid demand growth over time
U.S Electric Grid Demand – 1920 – 2020
| Year | U.S. Electricity Demand (GWh) | 20 year growth |
| 1920 | 35,000 | |
| 1940 | 80,000 | 129% |
| 1960 | 500,000 | 525% |
| 1980 | 2,800,000 | 460% |
| 2000 | 3,700,000 | 32% |
| 2020 | 4,000,000 | 8% |
This table contains some noteworthy information. Firstly, the average growth rate over the 20-year periods shown has been more than 200%. While this growth has decreased in recent decades, the earlier growth illustrates the US's potential when economic conditions are favorable. With this historical data, we can now consider how the 100% EV vehicle fleet fits into the incremental grid growth required to accommodate it.
Let's put the grid demand of 100% electric vehicles into perspective
If we add the additional demand from a fleet of 835,000 fully electric LDVs, which amounts to 835,000 GWh/year, to the estimated demand for 2020 and project that to the grid demand for 2040, we can anticipate a 21% growth over a 20-year period. See the calculation below for more details.
US Electricity Demand Growth from 100% Electric Light Duty Vehicle Fleet
| Year | US Electricity Demand (GWh) | 20 year growth |
|---|---|---|
| 2020 | 4,000,000 | |
| 2040 | 4,835,432 | 21% |
According to the table of historical demand growth above, there has been an average growth rate of 21% except for the most recent period which only had 8% growth. However, when looking at the growth rate over the past 100 years (1920-2020), the average growth rate was actually 230%. Therefore, the compound annual growth rate for the 21% growth rate is only 0.95%.
Key Points and Other Considerations
The answer to the question in the title is clear: achieving 100% LDV electrification is easily possible, even with U.S. economic investment in the grid below the historical growth rate. However, there are other opportunities to consider beyond just adding enough grid capacity to meet the increased demand for electricity. These opportunities include:
- programming electric vehicles to charge during periods of low grid demand
- installing solar panels at home for direct solar-powered charging
- using electric vehicle batteries to power a home for several days
These solutions rely on existing, mature technologies, and the only obstacles standing in the way are regulatory barriers and business inertia in the energy and transportation sectors.
The Wind and Solar Power and the Electric Vehicle
Each power grid is designed to produce the highest amount of power during the hottest hour of the year. At other times, some power plants are turned down or even shut off, resulting in underutilization. The chart below, provided by MISO (the Midcontinent Independent System Operator), which operates the grid in the Midwest, demonstrates this phenomenon.
According to the data, the average power consumption during off-peak hours from midnight to 7:00 AM was 71% of the day's peak load, and only 49% of the all-time peak of 127 GW. The company's website offers real-time data on grid demand, providing an opportunity to use grid resources more efficiently by deploying loads that can be dispatched - meaning they can be controlled to draw power only when there is extra capacity.
All current electric vehicles support automatic off-peak charging, allowing owners to set the charging time to coincide with the utility’s off-peak period. In most areas, a 100% EV fleet can charge overnight without the need for additional power generators. This not only benefits the environment but also the utility companies, who can sell more power using the same grid resources.
By offering lower off-peak rates (time of use or TOU), EV charging becomes even more affordable for drivers. Investor-owned monopoly utilities are required to pass along cost savings to their customers, so all customers benefit from the increased utilization of grid resources that comes with dispatchable loads such as electric vehicles.
Grid Capacity & Load Balancing
Grid load balancing involves managing and distributing the electrical load on the power grid in real-time to ensure a match between electricity supply and demand. The process comprises adjusting generation and consumption to maintain grid stability, prevent blackouts, and optimize the use of available resources. Electric vehicles play a significant role in grid load balancing and stability.
Electric vehicles can participate in demand response programs, adjusting their charging or discharging patterns in response to grid conditions. During periods of high electricity demand, EVs can reduce their charging or discharge their stored energy to support the grid. Conversely, when renewable energy generation is high, EVs can be charged to utilize excess electricity. EVs equipped with V2G technology can draw power from the grid and return electricity back to it, acting as distributed energy resources. By intelligently managing the charging and discharging of EV batteries, the grid can effectively utilize the large distributed energy storage resource represented by EVs.
EVs can provide grid frequency regulation services, helping to maintain a stable frequency within acceptable limits. They can also shift electricity demand from peak to off-peak periods, reducing demand during peak periods and optimizing the integration of renewable energy into the grid. In areas with limited grid infrastructure, EVs can provide localized support during power outages or emergencies, supplying electricity to critical infrastructure or acting as mobile power sources.
By leveraging the capabilities of EVs, the grid can better accommodate the variability and intermittency of renewable energy sources, enabling a larger percentage of renewable electricity generation while maintaining grid stability, reducing carbon emissions, and fostering a more sustainable energy system. Achieving a 100% EV scenario will require collaboration between governments, utilities, and private entities to ensure a smooth transition to an EV-dominant transportation system while maintaining a reliable and resilient electric grid.