In the Q4 earnings report, Tesla provided some update details on the Model Y. In addition to it being way ahead of schedule and set for first deliveries in March 2020, Tesla now says the Model Y AWD (note that RWD is not offered in the online design studio) goes an EPA-estimated 315 miles per charge. That's a huge improvement over the previous figure of 280 miles provided by Tesla.
Even more impressive is that both the dual-motor Long Range and Performance variants are both listed at 315 miles:
How did Tesla improve the range by so much though? As Tesla states:
Due to continued engineering progress of the Model Y all-wheel drive (AWD), we have been able to increase its maximum EPA range to 315 miles, compared to our previous estimate of 280 miles.
This extends Model Y's lead as the most energy-efficient electric SUV in the world.
Engineering has improved efficiency dramatically, it seems. Tesla even provided a chart showing just how dominant the Model Y is in regards to efficiency in the electric SUV/crossover segment:
As you can clearly see from the image above, the Model Y trounces the competition when it comes to efficiency. The Model Y exceeds 4 miles per kWh, whereas no other car on the list even passes 3 miles per kWh.
Efficiency has long been an area where Tesla excels and it seems that trend will continue with the Model Y.