BMW's Concept X5 eDrive has a lot to prove. Unlike its much smaller cousin, the i3, which was built from the ground up to be an all-electric vehicle, the plug-in hybrid X5 has to be equal (or pretty close) in drive experience to existing versions of this large, powerful car--BMW calls it a Sports Activity Vehicle--equipped with a traditional, internal-combustion engine.

BMW is hedging its bet big-time by putting in a huge, 70kW (95 horsepower) lithium-ion battery. This is a bigger battery than most all-electric vehicles have these days: The Tesla Model S has 60kW and 85kW battery options, for comparison.

BMW claims that on the battery alone, the Concept X5 eDrive has a range of 19 miles at speeds up to 75 mph. As a hybrid, BMW says it can get as much as 60 mpg. This fuel efficiency would be a big step up from the traditional X5's 22 mpg to 31 mpg (depending upon the model). You can plug in the hybrid to add some juice to the battery, which saves you even more gas.

As the name emphasizes, the Concept X5 eDrive is an experimental car, not available for sale now, and its future is uncertain. All my colleague Nick Barber could do at the New York Auto Show was drive around with a courteous BMW representative (as you can see in the video report accompanying this story). But you can bet we'll test that all-electric range--especially the 75-mph part--if this car ever makes it to market.