Argonne National Laboratory says the energy density of battery powered vehicles will not be the same as gasoline powered vehicles until some time in the far distant future. Right now the lab people say, gasoline is 100 times more energy dense than a battery. That means you would need 100 lbs of battery to go as far as 1 lb of gasoline can take you. If that’s true, how are we ever going to get to parity between electric and gas powered cars?
There is one other critical factor to consider. Electric powertrains are far more efficient than powertrains powered by gasoline. In fact, in many cases, less than 20% of the energy contained in a gallon of gas actually gets converted to forward motion. The latest Toyota Prius has an internal combustion engine that is 40% efficient, but it stands at the top of the heap when it comes to engines.
Even assuming a gas engine is as efficient as the Toyota, it still has to transmit the power it makes through a complex set of gears in a transmission and a differential. By the time power gets to the wheels that do the actual driving, it has suffered significantly more mechanical losses. By contrast, an electric powertrain can be more than 90% efficient. That advantage tilts things in favor of electric cars.
Argonne Lab says in its latest report that just looking at the gas tank and battery is an “incomplete analysis,” which “ignores the impact of powertrain efficiency and mass of the powertrain itself. “When we compare the potential of battery electric vehicles (BEVs) as an alternative for conventional vehicles, it is important to include the energy in the fuel and their storage as well as the eventual conversion to mechanical energy.”
Weighing all the factors and adjusting for the differences between powertrain efficiency, Argonne Lab concludes that when it comes to driving a distance of 300 miles, gasoline and electric drivetrains will be equal to each other in about 30 years. “By 2045, BEV 300s will be comparable to conventional vehicles in terms of the energy spent at the wheel per kg of the powertrain mass.”
The Argonne Lab report does not consider price in its calculations. What it shows is that if we base the changeover from fossil fuels to electricity solely on energy density comparisons, it will come far too late for the environment. The key to keeping fossil fuels in the ground is to remove the enormous direct and indirect subsidies they enjoy and make their market price consistent with their total cost to society.
Source: AutoBlog Photo credit: Audi