One company in Calgary, Alberta, has a part fleet of Prius taxis (There is no city called St. George).
Use of heater and air conditioning reduce gas mileage. Hot coolant is circulated for heating.
The cold winter nights here require garage storage when 20-30 below zero when not in use; no problems in warmer months. Block heaters are available and in use here, but efficiency has been questioned. The car runs on the gas engine during warm-up. This from an owner I know here in Calgary.

Our electricity comes from a grid tied to U. S. as well as Canada, (remember the last big brown-out), mostly coal-fired generation. Proposed vehicles requiring battery-recharge will, of course, increase coal-fired generation of power.