What do you do with a fleet of surplus electric cars?

As their two-year leases to BMW's fleet of "Electronaut" test drivers expire, BMW ActiveE electric cars are now returning to the company.

2012 BMW ActiveE - Driven in Monterey, February 2012

2012 BMW ActiveE - Driven in Monterey, February 2012

So BMW has chosen to redeploy some of them in the San Francisco Bay Area as electric-car rentals in its DriveNow car-sharing program.

The ActiveE is a BMW 1-Series two-door converted to electric propulsion and leased to customers o gather real-world data on electric-car usage, some of which fed into the design of the radical new 2014 BMW i3.

While many ActiveE Electronauts are about to switch to the i3, not all will--for reasons including the new car's price, polarizing styling, and the availability of more alternatives on the market compared to 2012, when the ActiveE was launched.

MORE: BMW ActiveE Electric Car First Drive: What's It Really Like?

With U.S. i3 deliveries underway, Electronauts in the Bay Area--and, more importantly, drivers at large--will still be able to get behind the wheel of an ActiveE, but they won't be able to take it home for good any longer.

DriveNow will add 80 ActiveE plug-in cars to its Bay Area fleet, increasing the total number of cars to 150.

The newly-added cars will allow DriveNow to add street parking, already available in the European cities where the service operates.

That means drivers will be able to pick up and drop off cars from select on-street parking places in San Francisco. They currently have to be returned to one of 17 service centers.

MORE: 2014 BMW i3: First Drive Of BMW's Radical New Electric Car

A smartphone app and an in-car screen will alert drivers when they reach a "green zone" in San Francisco's Mission District where a car can be dropped off.

These zones will launch on specific streets between Potrero Avenue and Folsom Street, and between 16th Street and 26th Street.

2014 BMW i3 (German-market version), Amsterdam, Oct 2013

2014 BMW i3 (German-market version), Amsterdam, Oct 2013

Both the ActiveE and i3 use 125-kilowatt (168 horsepower) electric motors, but the ActiveE has a larger 32-kilowatt-hour lithium-ion battery pack distributed in sections in its tunnel, under the rear seat, and replacing the gas tank.

The BMW i3 uses a smaller 22-kWh pack in its floor; the much larger pack of the heavier ActiveE gives it a slightly longer EPA-rated range of 94 miles, compared to 81 miles for the i3.

However, the i3 has an efficiency rating of 124 MPGe, against the ActiveE's 102 MPGe.

That rating makes the i3 the most efficient battery-electric car sold in the U.S. today--and unlike the converted ActiveE, it's a clean-sheet design that's among the most radical ever from BMW.

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