Ringside: EVs and California’s Future Demand for Electricity

When it comes to the achievement of “carbon neutrality” and the requisite energy policies to get there, few choices carry with them more consequences than the planned, nearly total electrification of our economy. And when it comes to electrification, few categories of consumption are likely to outweigh the demands of EVs. With a focus on California, how much demand are we talking about?

When it comes to making an estimate for EVs, we can predict with reasonable accuracy the efficiency of the power use, because EVs use electricity very efficiently. When at least 80 percent of the electrical energy charging the battery then powering the motor is returned as horsepower, which is already true, the theoretical limit of underestimating improvement in battery and motor efficiency is only 20 percent.

With that in mind, we can look up the total miles driven per year in California, and divide that by an average kilowatt-hours per mile (the EV equivalent of MPG). According to the US Dept. of Transportation, Californians drove an estimated total of 340 billion miles in 2024. According to the U.S. Dept. of Energy, the average EV gets 3.6 miles per kilowatt-hour. Simple division yields 94.4 billion kilowatt-hours. Since one million kWh equals one gigawatt-hour (GWh), then electrifying California’s vehicle fleet would require 94,444 gigawatt-hours per year.

This estimate may be lowered by the fact that about five percent of California’s vehicle fleet is already EVs, which lowers the mileage total represented by gasoline powered vehicles. According to the U.S. Dept. of Energy, of the 30.8 million cars and light trucks on the road in California, 1.6 million are “BEVs.” Another way to make this estimate is to consider the total gasoline consumption in California, multiply that by the average mileage, then divide the product by the average kWh per mile.

According to the California Energy Commission, in 2024 the state’s refineries produced 13.4 billion gallons of gasoline. They also report that “3% of gasoline in California is used off-road, and an additional small percentage is shipped out of state.” If we assume that lowering 13.4 by five percent will adequately take into account off-road and out-of-state use, we get 12.7 billion gallons.

The next step is to divide estimated gasoline consumption of 12.7 billion gallons by the average mileage for cars in California. A 2024 study by the Union of Concerned Scientists reports a 29.0 MPG average. This seems reasonable. There are way too many big cars, light trucks, and old gas guzzlers still on the road for California’s MPG average to be much higher. Using that figure, the division yields 389 billion miles driven, and based on that estimate, and at 3.6 miles/kWh, we come up with a 107,944 gigawatt-hours per year requirement to convert our vehicles to EVs.

The estimates arrived at using two methods, 94,444 GWh vs 107,944 GWh, differ by 14 percent. That may seem like a lot, but when we are trying to roughly estimate what it’s going to take to convert California’s drivers to all-electric vehicles, it remains a very useful number. And since we arrived at the two calculations using different starting variables, we can feel more comfortable that nothing is way off.

But California’s state legislature doesn’t just want to electrify cars and light trucks. They want to electrify everything on the road. So what about diesel fueled vehicles?

According to the California Energy Commission, 3.5 billion gallons of diesel fuel were refined in California in 2024, and according to former CEC Commissioner James Boyd, about 2.6 billion gallons were used for transportation. To translate this into kilowatt-hours requires a few big assumptions, but for making reasonable approximations for these numbers we can assume as follows: The average 18 wheeler heavy truck gets 6 MPG, and a diesel fueled F150 pickup gets 20 MPG. Let’s therefore assume that on average, diesel fuel consumed in California delivers 12 MPG. On that basis we can multiply 2.6 billion miles by 12 MPG and estimate 31.2 billion diesel fueled miles are driven per year in California. But how do you convert that to gigawatt-hours?

A shorthand that will likely yield a plausible estimate is to compare the average 29 MPG of gasoline fueled vehicles to the 12 MPG average we’ve assumed for diesel fueled vehicles. This ratio, 41 percent, is a basis from which to estimate how much more power is required to move the heavier diesel powered vehicles. Put another way, if we multiply 3.6 miles/kWh by 41 percent, we get a diesel vehicle estimate of 1.5 miles/kWh. Thus, divide 31.2 billion by 1.5 and the result is another 20,900 GWh per year to power California’s diesel cars and trucks with electricity.

Altogether, we may estimate with some confidence that it will take somewhere between 115,000 and 130,000 GWh per year to electrify 100 percent of California’s wheeled, on-road vehicles. Is that estimate too rough? Too speculative? Perhaps. But I’d be surprised if it differs significantly from what may ultimately be the case.

The big question – along with just how rapidly Californians will be willing to exchange their gas and diesel powered cars and trucks for EVs, or how rapidly the distribution infrastructure could be built – is where all this additional electricity is going to come from. We know that total consumption of electricity in California in 2024 was estimated to be 278,338 gigawatt-hours, so if we convert our cars and trucks to EVs, it could jump to over 400,000 GWh per year.

There will be other surging demands if California electrifies other major sectors of the economy. Can we electrify our locomotives? Will we electrify every cooktop and space heater, every pump, and most commercial and industrial processes? According to the US Energy Information Administration, California’s annual consumption of “energy services,” that is, end user consumption of energy, is around 2,400 TBTUs (trillion British Thermal Units), with nearly 80 percent of it converted from massive inputs of petroleum and natural gas.

Those 2,400 TBTUs, expressed as units of electricity, are equal to 700,000 gigawatt-hours. We then must account for the fact that even with solar and wind generated electricity sources, significant production percentages are lost in the transmission, storage, and ultimate conversion of generated electricity into light, heat, horsepower, etc. In order to electrify 100 percent of California’s economy, annual electricity production would need to exceed one million gigawatt-hours.

That doesn’t take into account the latest burgeoning use for electricity, AI, demanded by one of the most powerful special interests in the state, big tech. Over the next several years the tradeoffs our elected officials must negotiate between affordability and adhering to “carbon neutrality” are going to become more challenging than ever.