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Here's the way I look at it. The progress of every technology has a limit. When you reach the limit you have to change technologies or explore other options.
Efficiency
For an example one of the biggest contributors to better fuel mileage has been increases in engine efficiency. Back when steam cars were replaced by gasoline cars the efficiency doubled from 5% efficiency to 10%. With time that doubled again to 20% efficiency. Now we have cars that get double that at 40% efficiency. But how many more times can we double engine efficiency. Only one more time, which may not be possible with ICE's but is possible to get with EV's. But after we make EV's (or ICE's or whatever else) 99.9% efficient there isn't going to be any major gains to be had in the efficiency department. And even to get to that point of near 100% efficiency the costs may make it too impractical for mass production.
What next?
So how else can we improve mileage? Two major things come to mind, aerodynamics and rolling resistance.
The future of aerodynamics
Now aerodynamics have come a long way too from the early days of the horseless carriage. But there's still a long way we can go. And unlike the cost of desgning a 99% efficient charger, battery, motor controller and motor, the cost of a more aerodynamic shape is not necessarily going to cost that much more.
There are three ways in which we can lower the aerodynamic drag. One way is to just drive slower. I'm not sure everyone would be on board with this one though.
The second is to make cars have a smaller frontal (or cross-section) area: shorter, skinnier, and (if you really need the room) longer. Of course we can only make cars so short and skinny before they become impractical.
The third way is the shape. How close can we get to an ultra-aerodynamic tear drop shape? We already know the limit, it's about 0.045 coefficient of drag, about 1/5 of that of most modern cars.
In other words if we want to cut the aerodynamic drag by 80% we could either cut speed limits by about 60%, shrink down modern car shapes by 65% shorter and 65% skinnier, or just make the shape nearly a perfect 0.045 Cd, or do a little of each.
Rolling resistance
The next biggest energy sponge to deal with is rolling resistance. Of course we also have limits here as well. But lots of older cars weighed a lot less than modern cars and with older materials, so ligher cars should be possible. If we could make cars weigh half of what they do then rolling resistance would be not quite half of what it is (assuming that the people and cargo don't lose weight too.)
Of course the BEV presents a problem with it's ginormous battery. Maybe we should be settling for smaller range EV's anyway though. The Nissan Leaf battery could be nearly 1/3 it's current weight with the right batteries. But the current trend to people wanting a 500-mile range battery is a problem for reducing rolling resistance. Unless we could do something other than rubber tires. Maglev? Metal rails?
The point
The point is that if we continue to do what's being done now, there won't be any major increases in overall energy consumption. We won't be able to significantly increase engine/motor efficiency like has been done in the past since there's no way of doubling the efficiency of an ~90% efficient EV motor. The current box vehicle shape will never be much below the ~0.250 Cd that it stands at currently, and not anywhere near the 0.045 it could be. And if something isn't done to figure out how to significantly reduce vehicle weight, a lot of energy will continue to be waisted in heating up rubber and pavement.
And all this means that humanity will either have to give up on the idea of motorized transportation or continue to burn up massive amounts of fuel, use up massive amounts of battery materials, and keep using up other valuable resources unless people start going in the direction Aptera is headed. Make and use vehicles that use significantly less energy than they currently do.
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