They both plug in, they can both carry six-figure price tags, and they're from two of the most forward-looking automotive brands in the world. Beyond that, however, there are huge differences between the Tesla Model S all-electric luxury sedan and the BMW i8 plug-in hybrid sport coupe.
While both are good-looking, the Tesla is sometimes mistaken for the large Jaguar XJ sedan in its low, sleek, fastback shape. It's actually a hatchback, with a rear liftgate that opens into a cargo compartment that can be fitted with two rear-facing child seats—complete with four-point safety harnesses—to expand its passenger count to seven.
The BMW i8, on the other hand, is a jaw-dropping exercise in futurism, with bird-wing doors that rise up from the windshield pillars to let two occupants drop as gracefully as possible into their form-fitting seats. Its characteristic BMW twin-kidney grille is actually a pair of blanking plates, and its silver and blue accent coloring denotes that it's a member of the BMW 'i' family of plug-in electric cars.
The Tesla is purely a battery-electric car, with a large flat 70- or 85-kilowatt-hour battery pack under the floor from doorsill to doorsill, axle to axle. Most models now have all-wheel drive, with a larger motor on the rear axle and a smaller one between the front wheels. Rated electric ranges vary from 240 to 275 miles, depending on what model you order. And the hot rod of the range is the Model S P85D, with acceleration times from 0 to 60 mph of roughly 3.0 seconds—which has produced dozens of videos of stunned passengers.
With two separate and sometimes-independent powertrains, BMW's i8 is a bit more complicated. At the back, a high-output turbocharged three-cylinder drives the rear wheels, while an electric motor up front powers the front wheels. As a result, the i8 can run on electricity alone, as a sporty hybrid, or with both operating together for maximum performance—when it becomes what engineers call a "through-the-road hybrid." The two modes of propulsion are coordinated by control software, not a mechanical connection, when they are used together for all-wheel drive and maximum performance.
Both cars are fast, but the Tesla is the smoother, quieter, and more consistent, simply because it never switches on a combustion engine. The "D" all-wheel-drive models have superb traction, with power to each wheel modulated many times a section to ensure that no wheel ever slips—and that the more energy-efficient of the two motors is used at any one time. Like most plug-in hybrids, the i8 has different driving characteristics when it's running electrically (at lower speeds, and not under full acceleration) than when both powertrains are in use—especially in the Sport mode that uses the battery to provide added torque when demanded.
The BMW i8 has the edge for faster long-distance travel—for one or two people, anyhow—because it can refill at gasoline stations as needed. But Tesla's network of Supercharger fast-charging sites has spread rapidly across the U.S. in the last three years (and globally too). Coast-to-coast trips in the Model S are eminently a reality, with 20- to 40-minute stops every 200 miles or so to recharge.
Inside, both cars are comfortable, with the BMW's two bolstered seats especially good. (We're also fond of the optional turquoise seatbelt straps, a visually compelling design feature.) The Tesla seats four adults comfortably, five acceptably, though rear outboard passengers will find the roof leaning in toward their heads more than in other, more upright luxury sedans. The finishes of its interior pretty much disguise that fact; like other cars at its price, it is trimmed with soft-touch materials, leather, brushed chrome, and other high-end materials. The Tesla's finishes, by contrast, are fine but perhaps slightly more stark.
The BMW dash will be relatively familiar to existing BMW owners. It's not nearly as radical as that of the BMW i3 electric hatchback, while the Tesla's dominant feature is huge 17-inch color vertical display occupies the center of the dash and provides a focal point for a clean, almost stark interior design. The Tesla screen's brightness, clarity, and instant response put other luxury brands' smaller screens to shame.
Tesla wins uniformly high safety scores for the Model S, though it was a little slower to fit advanced electronic safety systems like adaptive cruise control than were some of the German competitors. The company now promises both self-parking and autonomous highway driving under some circumstances within the next year or so.
The BMW i8 has not been crash-tested, and its very low volume may prevent that from happening. When the more common BMW i3 is tested, however, we'll be able to draw some lessons on how both cars' unique construction does in such tests. The i8, like the i3, combines an aluminum rolling chassis containing the battery, the running gear, and the crash structures with a body shell made of carbon-fiber-reinforced plastic (CFRP) that is both lighter and stronger than either steel or the Tesla's aluminum.
The Tesla Model S starts at $75,000 for the new base '70D' model, and can top $130,000 for a P85D performance version loaded up with extras. The BMW i8 starts at $135,000 and can cross the $150,000 mark with options. Both qualify for a variety of federal income-tax credits and other state, local, and corporate incentives.
in the end, while the BMW i8 is by far the more striking car—we counted 15 separate people taking photos of it simultaneously on Rodeo Drive when we opened the winged doors—the Tesla Model S is smoother, quieter, more capacious, and somehow more impressive. Either will get you noticed, but the Tesla Model S wins the comparison for being the most practical electric car the world has yet seen.