The best green cars you can buy

Welcome to Top Gear magazine's round up of The Best Cars In The World. That might seem a trite observation, but after much deliberation, haranguing and three bouts of raised voices, the vehicles we will present to you over the coming week represent the cars that TG magazine would happily recommend to family and best friends, without reservation.

Any of these cars - within their brief - are the best at what they do. They are the TG benchmarks, the class leaders.

There are three loose price points to scale our ambition: an attainable version, an aspiration and a dream.

So, allow us to guide you through the cars you should consider before all else. Today, it's the really efficient stuff...

----------

In the infant years of any technology, different inventors propose diverse solutions. Look at the heterogeneityof powered heavier-than-air flying machines in the decade after the Wright brothers took off in 1903, or of smartphones in the decade after 1996's Nokia Communicator. But, in the end, some sort of consensus gets established. With electrified cars, we've not yet recognisably arrived at that moment of convergent evolution. Actually, because the technology offers so many possibilities, it'll be a long time before we do. If ever.

Anyway, it's a pretty startling fact that these three cars, all well-developed and fun to drive for several miles on pure electric, are among us at all. Just four years ago, you couldn't buy any plug-in car in the UK. Only the dire G-Wiz and other cyclecars.

Pictures: John Wycherley

This feature was originally published in the September 2014 issue of Top Gear magazine

In the Zoe we have a steel-bodied pure electric car. And an essentially similar concept with the Ampera, but with less battery, and an added range-extending petrol engine to generate power when the battery's flat. And then, oh boy, the i8. Like the Ampera, it can act the front-drive EV till its battery depletes, but it doesn't give its full supercar performance that way. For the total effect, a mid-mounted petrol engine, itself capable of generating power for the front motor, turns it into a full-range 4WD supercar.

But because they need to save energy, all three cars share principles. They roll along on the bare minimum of energy - at steady speed, accelerating and then when you brake, scooping back kinetic energy and reconverting it. Which means light weight, slippery aero, low friction and a clever power unit. And doing these things with commitment means going through the whole car, repackaging it so every system works optimally with every other. It'd be a bodge to take a regular vehicle, rip out the normal powertrain and stuff into its place something vaguely science-project.

No, the depth and elegance of engineering that inhabits these cars informs their aesthetics and deepens your relationship with them. But it's not all cerebral. They're fun to drive too, each in their own sweet way.

The i8 is green done theatrically. Its swan doors allow the aerodynamic taper of the cockpit. You drop into its narrow, minimalist but materially rich cab. Sure enough, you're in a tight metaphorical embrace with it as you drive, a sensory exchange. Even - maybe especially - in its electric and eco-hybrid modes. You operate it with extreme concentration, tailoring your inputs to maximise efficiency. You yearn to be worthy of it.

But... the devil adds his own option. Nudging the transmission lever to the other side, you feel the dampers and throttle tense up, the gearbox get more aggressive. Even the engine comes over a bit guttural, thanks to some augmentation via the hi-fi - the auditory equivalent of botox, but less risibly artificial. Now it's a real sports car, cornering sharply, clamping itself to the curve, accelerating like it really means it. Did you know there's even a second e-motor, bolted to the engine, tasked with giving a pulse of torque to cover the lag before the turbo spools up?

At the other extreme of this trio, the Zoe might be sold on the strengths of its eco and money-saving figures. But, heck, it's just a brilliant urban supermini, full stop. It's softly sprung, and its c of g is worm-low. Full-electric drive gives it smooth step-off, quick-witted and step-free acceleration and a perpetual, blissful silence. Even the cabin, furnished in light colours and simple shapes, gently sponges your mind clean of naughtiness.

The Ampera also glides silently in EV mode, cushioning you both mentally and physically with its seamless but decently swift drive and its soft suspension. Plus, of course, it erases the anxiety of being marooned with a flat battery. Once the EV range is depleted, the engine softly whirrs up and you proceed unabated. It actually has two motors. One always drives the wheels, while the other can either add its efforts to increase performance or act as a generator when the engine's on.

The i8 adopts - then subverts - the technical habits of the hypercars de nos jours. It has a carbon- fibre tub and electric-hybrid powertrain, wrapped in a body whose shape is rooted deep in the wind tunnel. Because computers control the torque split between electric front and petrol rear, and because the weight is low and central, you get a car that'll scoot round corners far better than those tyres might hint. It's a sports car, and a proper one: those digital processes produce a nicely analogue feel.

To cut flab and resistance, any unnecessary particle in the i8 has been hacked away. It doesn't just grab off-the-shelf suspension arms or even wiper assemblies; it uses bespoke jobs to be lighter. And what beautiful pieces they are. The window glass is a thin but extra-tough grade normally used for phone screens. The Ampera sometimes turns on its electric seats to save the efforts of its heater. Its hi-fi uses efficient amplifiers and low-mass neodymium speaker magnets. The Zoe uses a super-efficient heat pump to warm the cabin.

Do you need to go faster than 84mph in the Zoe, 100mph in an Ampera or 155mph in an i8? Nope, so they have electronic limiters. This means the brakes can be lighter, and the bodies lower in drag because they have no need to avoid lift at irrelevant speeds. The Ampera's low-drag body gives it about eight more miles electric range than if it were shaped like a normal hatch.

And so to their headline-grabbing economy. Disclosure: the i8 and Ampera (pictured) get their energy from two sources, plug-in electricity plus petrol. So their official fuel figures aren't transparent because that electricity isn't included. What you'll actually get depends on how often you do plug them in, or how much you just run them on petrol. Given you can probably do 40-odd miles in the Ampera, if that's your commute, you'll never add fuel. Our long-term test car went half a year on one visit to a petrol station.

After the battery is down, the i8 and Ampera operate as normal low-drag hybrids. That allows the engine to be downsized to a 1.5-litre turbo triple in the BMW. The Ampera runs a 1.4-litre, which doesn't need to be complicated because it runs as a generator at almost constant rpm. So, even under petrol power, they're still pretty economical.

Renault's approach is more straightforward. The Zoe has only the electric system. That means it chucks away the engine, gearbox, cooling system, exhaust, cat and fuel tank. Which frees up a lot of money, weight and space to spend on a bigger battery. The Zoe's range is 70-80 miles real-world, unless it's wintry, in which case expect 60.

The Zoe's price matches an ordinary supermini. OK, on top of that there's battery rental, but the monthly fee is set to match that supermini's fuel cost. Fair dos - most of us don't truly own our phones as they're subsidised by paying monthly. It also means if the battery degrades over time, that's Renault's problem.

But don't think only of the running costs in a Zoe. Or in the other two. Nor are they just about saving the planet. They are all a good drive, all of them punchy and yet peaceful. (Unless the i8 is in supercar mode, which it can be whenever the road allows.) They engage deeply with your brain, because they work so much better if you understand and work with them. It's no drudgery, because they're so actively fascinating. They're cars that give car enthusiasm a whole new dimension.