If you buy an EV (electric vehicle) over an ICE (internal combustion vehicle) for city travel and run it exclusively from the grid, the answer is an emphatic ‘yes’:
you will moderately to significantly reduce your CO2-e emissions as compared to an equivalent ICE vehicle for all Australian power grids. (See graph 1) above.
The answer is slightly nuanced in that if you replace the ICE with an EV for all travel (i.e. meet the criteria for the combined vehicle test cycle).
In this scenario, the answer changes for one state. That state is Victoria, where the BMWi3 CO2-e is 5.3% greater than for a 2017 Corolla – although this is not really a like for like car.
However, given average ICE fuel consumption figures have significantly reduced over the previous decade or more (see 2012 versus 2017 data for the Corolla in Graph 2), it follows that replacing an older ICE vehicle with a new EV improves this equation in favour of the EV in Victoria, and further improves the figures in favour of the EV for all other Australian states and territories.