Not sure if it was covered in your episode, but there’s a couple of paradoxes that also call hybrid efficiencies into question.
Here in the SF bay area, a large number of drivers choose the Toyota Prius, and then choose to drive aggressively, recklessly, and inefficiently. Maximum MPG is gained when the car is near idle but in the highest gear (or its equivalent for CVT), so most hybrids have a nice sweet spot between 45 and 65 mph. If you travel faster than this, you are simply burning gas to save time. Then, in traffic, I will see both aggressive lane changing, and accelerate-to-stop to prevent other people from lane changing. These actions often fire the gas engine, and put a limit of efficiency. Also, accelerating to a stop sign, red light, or traffic snarl defeats the small amount that regenerative braking regains.
You don’t have to be a hypermiler to realize that some retraining your usage of the hybrid or electric car is needed to gain all of the green benefits of ownership. A return to 55 mph limits could also greatly benefit the environment, but voluntary practice of this can add around 10mpg in my own usage.
Lastly, everyone wants to think that the electricity pouring out of the wall is curated by magical elves who give you the greenest electricity. If you charge during peak usage, you’re getting either baseline electricity or peak gas-fired electricity.
The smartest thing drivers could do is make greater use of cruise control. Although every car has it, almost no one seems to use it, based on my observations driving under cruise control. Randomly speeding and slowing, and failing to take advantages of natural rises and falls, and exceeding the maximum efficiency point of your auto, are all anti green practices.
If we are ever to push adoption of self driving cars, we need to wean ourselves of the habit of feeling we can exceed posted speed limits and jump queue and agress people out of our way. When we reach 60–70% usage of cruise control on roads faster than 40mph, we will see both gains in average fuel efficiency, fewer accidents from aggressive driving, and a cultural shift that will allow the car to make more of the decisions.
I am not holding my breath.