The numbers currently vary widely. Other sources speak about 150.000km (≈ 93.000 mi) which would result in 16% reduction of emissions compared to diesel and 24% compared to petrol. It depends how the life-cycle of the car is calculated too and there are still some unknowns. This also presumes the electricity comes from renewable sources and this is also restricted to carbon emissions.
Whatever the real number might be, large scale adaptation and longevity of cars is necessary to make it a good deal for emissions.