After a long incubation period, the first cars released under BMW's sustainability-focused "i" sub-brand – the i3 city car and i8 sportscar – have been hitting roads around the globe throughout 2014. We climbed aboard the i3 to find out how it performs.

We've previously looked at the make-up of the i3 in detail, but here's a quick refresher. It's a compact four seat, five door that's a touch under 4 m (13 ft) long with short overhangs at both ends and an exceptionally tight turning circle of 9.8 m (32 ft – that's 10 percent less than a Mini) and 2.5 turns lock to lock.

The BMW-developed electric motor is located at the back, providing 125 kW and 250 Nm (184 lb-ft ) of torque to the rear wheels through a single speed automatic transmission. In addition to the battery electric vehicle (BEV) model there's a range extender version in which a 34-hp, 650 cc two-cylinder petrol engine from BMW Motorrad sits alongside the electric motor and acts as a generator (i.e. it charges the battery but, unlike hybrid cars, it doesn't drive the wheels).

The modular 360 V, 21.8 kWh (18.8 kWh useable), 96 cell, liquid-cooled lithium-ion battery pack is spread across the underbody and can be charged in 11 hours using a domestic wall plug or six hours using BMW's i Wallbox. BMW says DC fast charging can deliver 80 percent charge in just 30 minutes.

On a single charge the i3 has an "everyday range" of 160 km (100 mi). Using ECO mode can bump that closer to 200 km (124 mi), while the range extender version can travel around 300 km (186 mi). Acceleration is put at 0-100 km/h (0-62 mph) in 7.2 seconds and importantly it still has plenty of zip for overtaking at higher speeds, with a 80-120 km/h (50-75 mph) time of 4.9 seconds, putting it on par with a BMW 435i. Top speed is electronically limited to 150 km/h (93 mph).

The i-series cars are based on an architecture that's been created "from the ground up" for electric vehicles. The passenger cell is the first mass-produced using carbon fiber-reinforced plastic (CFRP) and the chassis is made of aluminum and other lightweight materials. This adds up to a car that weighs just 1,195 kg (2,634 lb) – the range extender adds around 120 kg (265 lb) to that figure.

A fine line, by design

Faced with the challenge of creating an entirely new sub-brand for a new type of car, BMW designers have done an admirable job in walking the line between making the i3 stand out from the crowd, while at the same time making it perfectly clear that this is still a BMW ... though the result won't be to everyone's taste. The familiar BMW face is still there with the twin kidney-shaped grill surrounds (though because there's no radiator, there isn't actually a grill to surround) and the BMW badge front and center.

The U-shaped headlights add a point of difference, as does the distinctive swoosh on profile where the door line drops before tapering back towards the roof line at the rear. The teardrop effect of this "Streamflow design" delivers a Cd figure of 0.29, which falls short of the Toyota Prius (0.25) but isn't bad for a car with a relatively high seating position. The U-shaped lights make even more of an impression at the rear where there's also a thin (2.85 mm) glass tailgate unique to the i series.

The carbon fiber passenger cell means that there are no B-pillars, enabling the use of rear-hinged rear coach doors that make access to the rear seats easier (something that would be particularly useful if you are strapping in a child). On the downside, you can't get out without the front door being opened as the handle is positioned on the front of the door.

It's on the inside that the "newness" of the i3 really hits home. There's no central tunnel and the twin infotainment screens float above, rather than merge into the dash. There's three different interior design trim packages available – one with "natural leather" upholstery and two that sport a hip (but not too hip) mix of colors and textures and, in keeping with the focus on sustainability, BMW says that 25 percent of the materials used are recycled or renewable.

The first impression is of a look that's perhaps a little clinical, like you've stepped into the pages of Vogue Living and you're not not sure if you're allowed to sit anywhere. Still, that may be a result of the spaciousness of the layout and it is after all a premium car, so it should have a premium feel. It's certainly very comfortable when you do nestle in, with an SUV-like high seating position and a decent amount of room in the back and rear storage area, plus there's some extra storage space under the bonnet. The controls are easy to find, simple and intuitive. There's a start stop button and a rotating switch off to the side of the steering column for selecting the single speed drive mode or reverse.

Screen real estate is ample – a 5.5-inch display behind the steering wheel shows the state of charge and other essential driver info, and a centrally-positioned 10.3-inch screen for the infotainment, navigation and communication functions of BMW's Connected Drive system.

One pedal to rule them all

Around town this car is fantastic. It zips off the mark, turns on a dime, provides good visibility and it's whisper quiet – pedestrians will be pleased to know that there's an aural warning that's activated at speeds under 30 km/h (18 mph). Sure, it's a little weird initially – you don't get the same level of feedback as you do from a revving engine and you have to be careful not to enter corners too fast, but you soon get into the swing of it.

The i3 also makes good use of regenerative braking, which is speed sensitive so that at lower speeds the car pulls up quite quickly, while coasting at higher speeds. According to BMW this can reduce time spent on the pedal by up to 80 percent (and save on brake pads, adding to the low maintenance credentials of the EV). The system will pull you up to a complete stop, so you can drive through the city and barely need to touch the brake pedal. Again, a little practice is required, but after a short time this one pedal operation became second nature.

The city driving experience is further enhanced by a full suite of driver assistance tech, including cruise control with auto braking and automated park assist.

The really impressive thing is that the i3 also does the job on the open road. There is some road noise on the highway, which is obviously an added challenge for EV designers, but there's enough power on tap for overtaking at higher speeds, and despite its skinny tires and relatively tall stance, it's surprisingly well balanced through corners. There is some swaying as you flick from left to right, but with the aid of BMW's Dynamic Stability Control system the low center of gravity afforded by the 230 kg (507 lb) battery spread beneath your feet, the i3 much delivers much sportier performance than its looks might suggest. I had to stop myself halfway through a discussion with my driving partner about how the RWD i3 tends to understeer ... "why are we even talking about this – this isn't what this car is about."

Remember range anxiety?

We tested both the BEV and range-extender version of the i3. The key differences in the latter are the addition of the two-cylinder 650 cc motor/generator, a 9-liter (2.4-gal) fuel tank and slightly wider tires – and of course an extra 100-140 km (62-87 mi) of range – but apart from that, the vehicles look the same.

Although you can manually switch on the range extender when the charge falls below 75 percent (though not on US models), it's designed to kick in automatically when the battery level is in single figures. The engine runs at one speed to provide charge to the battery and, apart from the hum of what sounds like a big jar of flies in the boot, there's no difference to the driving experience. The noise isn't overly intrusive, but it does make you feel like you should be clicking up a gear, though of course, there's no shifter in sight.

So is the extra range worth the extra cost? We can't see a strong argument for it. The 160 km range of the BEV is more than adequate for most commuters. This is backed up by the company's extensive research with the Mini E and ActiveE, where many participants said that they wouldn't bother with a range extender next time around. It's also notable that part of the service procedure for the i3 is draining the fuel tank, because BMW doesn't expect customers to use the range extender much.

It's seems fair to say that the range extender version is just there to provide a soft landing for a driving public that isn't yet comfortable with the idea of a fully electric vehicle. After the experience of the i3 and other EVs we've tested in recent times, we'd have to say that range anxiety has a bark that's worse than it's bite. Customers will buy EVs as an economical urban runabout – that's what they are designed for and they are perfectly suited to the task. If you want to go touring, you'll likely switch to the other car in your garage, or plan accordingly … why worry about a car not being up to a job it's not made for in the first place.

Another optional extra we would be unlikely to tick the box on are the 20-inch rims. These make the ride noticeably harsher and given that aesthetically, you hardly notice the difference, we think the 19-inch numbers do the job just fine.

A new dawn?

The BMW i3 ticks a great many boxes – it's practical, fun, environmentally-friendly and economical (NEDC consumption is 12.9 kWh/100 km or 62 mi). It offers no-compromise city driving by doing what it needs to ... and more. It's still a premium car, with prices starting at US$41,350 for the BEV and $45,200* for the range extender version (including BMW i roadside assistance for 8 years and an 8 year/100,000 km warranty on the battery), so it's not going to transform the marketplace in one fell swoop, but the entry of a big player like BMW into the EV arena, and the fact that it has done so with such a holistic package undoubtedly lends significant momentum to the rise of the EV.

* In Australia, where this test took place, pricing is AU$63,900 and $69,900 respectively and running costs come in at $3.90 per 100 km using "green" electricity.

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