The Hygrogen Fuel engine that BMW are throwing millions at is a far
better proposition .. waste product is only water ... Hydrogen is easy
to produce and not a fossil fuel.
No heavy batteries to crat about (with dubious life)
They already have concepts up and running ... filling time at pump is
very fast, and the liquid hydrogen is stired in what sound like a
sponge, and is safer than petrol in the event of a collision.

Knowing BMW it will have a HUGE price penalty, as just about
everything is an extra (and very expensive extra at that)