An Antiplanner reader writes, what “if all vehicles in USA were powered by electricity?” The reader wasn’t sure, but suspected that it would be “impossible to do with electricity as now generated and distributed.” I was inclined to agree, but when I looked into it, the results surprised me.
First, as I’ve noted before, only about a third of the power used to generate electricity ends up being delivered to the end users; the rest is lost in generation and transmission. This would seem to reduce the apparent efficiency of electric cars.
Counter to that, however, internal combustion engines dissipate most of their energy in the form of heat. On average, only about 21 percent of the energy from burning gasoline or Diesel is used to move vehicles; the rest is lost. Electric motors, however, only lose about 20 percent of their energy as heat. This more than offsets the losses from electrical generation and transmission.
In other words, 100 BTUs of energy at the power plant delivers 33 BTUs to the end user, and an electric car turns that into about 26 BTUs of transportation. By comparison, burning 100 BTUs of gasoline in a car produces only about 22 BTUs of transportation. It is conceivable that we could save energy by burning that gasoline in a power plant and delivering it to electric car users.
Click image to download a PDF of this chart.
As shown in the above chart, out of the 97 quadrillion BTUs (quads) of energy Americans used in 2016, transportation used 27 quads. However, cars and light trucks used only about 15 of those quads. Converting those cars and light trucks to electricity would reduce their consumption to about 12.5 quads. Since our current electrical system generates about 37.5 quads, it might seem we would have to increase power generation facilities by about a third.
But that’s not necessarily true either. Electric power plants are rated by their ability to produce peak power, but peak power demands can easily be 40 percent greater than the minimal power demands. If electric car users increase demand by a third, but most recharge their batteries at night or other off-peak times, they won’t require a significant increase in power facilities. In fact, off-peak recharging could actually reduce electricity costs by smoothing out the demand over the course of a day.
Of course, some will want to recharge their cars at peak periods. But if power companies vary price according to demand, as a few have started to do, that will be offset by other people shifting their power use to off-peak periods. Moreover, if everyone owned electric cars, it would be faster and simpler to simply swap out discharged batteries for ones that had been fully charged the night before.
This doesn’t mean I am persuaded by claims that 95 percent of all travel in 2030 will be by electric vehicles. But I’m less worried that our electrical power system won’t be able to handle the demand.