[33W]

They also have an interesting somewhat-hybrid called i-eloop that uses regenerative braking and a capacitor to power auxiliary systems:

http://www.mazda.com/en/innovation/technology/env/i-eloop/

[SeanLuke]

I considered i-eloop when it came out for its first generation, in the 2014 Mazda 3. It was estimated to bump my city MPG by 1. And was only available in a very expensive package. I passed.

[33W]

I have a '16 Mazda 3 without. I agree that it is non-economical, but interesting.

I'd like to have it with a larger lithium-ion that can remote start only my AC for a few minutes while I walk to the car in the summer.