There' s nothing wrong with gasoline engines. Their emmisions have cleaned up. They provide alot (I know 'alot' isn't a word) of power compactly.
EVs are better of course. Torque-ridden simplicity is better. But, they have yet to be competitive in terms of packaging and cost. That'll happen soon, but for the mean time, gas engines aren't half-bad.
Besides, the t25's real accomplishment won't be its engine. According to their website, they're going to fit four people in a space that's 2/3 of a Smart, but they're still gonna earn the same 4 stars as the smart (in the euro's crash testing safety). Innovations in packaging can be applied to EVs too.