Though you could regenerate part of that on the way back down. As I understand it electric cars are well suited to Denver and other mountain regions as regenerative electric braking saves on brake pad wear.
You'd think so, but in practice my electric car is less efficient going over the mountains than driving a flat stretch.
So yes, they will be able to recover some energy on the way down and reduce wear on brakes, but they'll have to make sure their batteries are up to the task.
Regen isn't 100% efficient, but its a lot better than dumping the momentum as heat. The problem is that the horizontal distance alone from denver to many destinations like lake city is enough to drain a battery.
So yes, they will be able to recover some energy on the way down and reduce wear on brakes, but they'll have to make sure their batteries are up to the task.