Concept cars are awesome. They’re a chance for designers to let their minds run wild and an opportunity for manufacturers to show us the cars we could be driving in the future. The only problem is that they hardly ever make it to production.

That’s precisely because concept cars tend to look like Wacky Racers, with no thought for practicality, legality or even basic Physics. But there are exceptions and, just sometimes, they do actually hit the production line.

The BMW i8 is one recent example that sticks in the mind. That was just another madcap idea, but the world loved it so much that BMW went ahead. So it is possible. Here, though, are 10 awesome low emissions concept cars that we wished we could have seen in real life.

1 GM XP-21 Firebird

General Motors created the Firebird 1 in 1953 and there’s just no way this car was ever going to go into production. It’s basically a fighter plane for the road and as it came as the Cold War hit its peak. So it was as much a demonstration of national pride than a car.

It was lightweight at 2500lb and came with a fiberglass body. It was powered by a 370bhp gas turbine engine that could, theoretically, power the car to 200mph and beyond. It wasn’t the most fuel efficient car in itself, but it could have formed the basis for leaner, cleaner road cars.

It was the first gas turbine-powered car ever to be built and tested in the US and GM built the car to see if its engineers could master the turbine for road use. The car had all sorts of tricks we take for granted today, including double wishbone suspension.

Racing car driver Mauri Rose tested the car at the Indianapolis Speedway and the Firebird made such an impression that a miniature version now adorns the Harley J Earl Trophy. GM went on to make two more, but the original is still arguably the best.

2 Jaguar C-X75

There’s still just a sliver of hope that Jaguar could make the CX-75 happen, but we’ve kind of given up on seeing more than the one example the Leaping Cat produced for the press.

Jaguar swore it was going to happen when they launched the car in 2010 and struck a deal with WilliamsF1 to help it with the advanced tech on this $1 million car.

The whole project was cancelled in 2012, but this tech still looks good right now and this is a 205mph car, in theory, which could easily get quicker and really mix it with the likes of the McLaren P1 and LaFerrari.

It is a 778bhp supercar with four separate electric motors driving a wheel each and the batteries are powered by two diesel-powered micro gas turbines. Jaguar reckoned on an electric-only range of 68 miles and the micro turbines run on diesel, biofuel, LPG or Compressed Natural Gas.

The CX-75 could hit 60mph in less than three seconds and it looked stunning. But the global economic crisis was cited as the reason the project was canned. Jaguar then rubbed salt into that gaping wound by building seven replicas for the James Bond film, Spectre.

3 L’Oeuf

In 1942, the environment really wasn’t a big deal. The world was in the grips of World War II, people simply didn’t have money or materials and even fuel was precious. So Paul Arzens took lemons and made lemonade with a car that was literally called: The Egg.

The Frenchman built this three-wheeler from plexiglass and aluminum. He then fitted it with an electric motor and the whole kit weighs in at just 771lb. It produced approximately 10bhp and came with a range of 63 miles and even managed to hit 44mph, or 37mph with two people on board.

This was Arzens’ third prototype and they got progressively smaller and lighter as the war continued and petrol became increasingly precious. Arzens faced a wholly different set of problems, but he came up with a thoroughly modern solution and created one of the first environmentally friendly city cars.

It didn’t make it to any kind of mass production, but the car is still celebrated to this day. Not bad for a one-off concept.

4 Peugeot Egochine

Now this one is just nuts and there is just no chance you’ll ever see this car in the real world, ever, but we love it anyway.

Paolo Di Giusti is the artist responsible for this piece of automotive lunacy and it’s theoretically powered by hydrogen fuel cells in the fuselage towards the front. The driver sits far back in the rear and we kind of wonder if this three-wheeler could even function as a real car on a number of levels.

It looks epic, though, from the 50s style wheelarches and those industrial fans as a cooling system. Of course it’ a pure design study and it was a finalist in Peugeot’s own retrofuturist competition.

There are no power figures or even real details on the powerplant, just an insane concept of a car that basically looks like an ornate razor. The practicalities and common sense factors of building cars just don’t sully this particular equation, so soak in the madness and give it whatever powerplant you like. It won’t really make any difference.

5 Quant e-Sportlimousin

This one always looked like vaporware, but then it toured the same shows as the Rimac One, at the same time, so you just don’t know for sure. It was launched in 2014, technically as a production car, with a salt water battery. It just never really made it into production.

The Swiss company claimed it could hit 60mph in less than 2.8s and run to a top speed of 217mph, with an all-electric range of 317 miles when such a thing was totally unheard of. But the technology under the skin was as perplexing as it was intriguing.

Quant reckoned it could power the car with patented Flow Cell technology that essentially used an electrical charge to cause two electrolytic solutions to pass through a membrane and create power. It sounded cool, but there were a few problems with the Physics.

It looked awesome, with a four-wheel-drive set up, gullwing doors and a $1.7 million price tag that seemed as fanciful as the technology under the skin.

Quant seems to have given up on the powerplant and last year launched the Quant F, which is basically a reworked version of this car with an electric motor and Lithium-Ion batteries. The company is claiming 1075bhp and a 500-mile range, but we still don’t have the car in our hands and Rimac isn’t sweating just yet.

6 Tata AirPod

This car that runs on air made a splash a few years ago, then went quiet. Indian company Tata brought the concept back and we keep hearing about a production schedule, but it hasn’t quite happened yet.

Luxembourg-based Motor Development International (MDI) built the air car and then Tata took control. With one of the world’s biggest car manufacturers behind it, the AirPod could be a smash hit. If it works.

Tata reckons on a top speed of 50mph and a range of 124 miles, all with the power of compressed air. It seats three adults and a child and Tata targeted a price of $10,000.

This car has come so close to general release more than once and there must be some technical issue that we just don’t know about. That’s a shame, because compressed air is about as cheap as it gets and Tata claimed it would cost just $2 to cover that 124-mile range.

7 Ferrari Eternita

This was another design competition winner and Ferrari was so impressed with the work of a team of South Korean students that it mocked up this hydrogen fuel cell car.

It is just one possible future design direction for Ferrari that asked for cars that we could see on the road as early as 2025.

We’re still not quite sure how the rear wheels are supposed to work and it will need a full windscreen or it will get really drafty at 200mph, but we like this car and could easily see this being the range-topping Ferrari in a clean, pure future world.

There’s not much else to add about this concept at the moment. It could come with hydrogen or battery power, depending on which power source wins the day and it will have to deliver modern day supercar performance to make good on the promise of that ridiculously low-slung body.

8 Rolls-Royce Vision Next 103 EX Concept

This is another one of those dreamy looks into the future to a time when there is no need for an engine, or a driver. So basically it’s autonomous tech a few years in advance and this car could technically be on the street in less than two years.

But we’re going to go out on a limb here and say if you ever see anything remotely resembling this car with a Rolls-Royce badge on the front then we will eat our own hair. It’s absurd, it’s outlandish and it’s kind of fun, but there is just no way this car is ever going to hit the showroom.

The point of the 103 EX Concept is that every car is bespoke, you can do what you want. So not everyone would go full Wacky Races like this squared off chunk of eccentricity, but you could in this parallel concept universe.

The grille does nothing here, but it looks the part along with the backlit, blown glass Spirit of Ecstacy. The square wheel covers could be aerodynamic and reduce wind resistance, we suppose, but apart from that the concept is full of neat touches like a luggage compartment in that long nose.

In fact, the car is 20-feet long in total and yet still manages to pull off ‘delicate and ornate’. It’s a stunning looking thing, if nothing else.

9. Peugeot Honey B

This black and yellow hunk of madness that could have seen active service on a lunar landing was introduced in 2007 and it is meant to represent a futuristic SUV. It also earned Peugeot a second spot on the list.

This off-road minibus features an innovative inline seating layout with a cockpit-style cockpit opening for each occupant that means the entire canopy is produced from plexiglass that gives a panoramic view.

Honestly we don’t think it would work too well on the road and with the low slung and long body it looks like it would beach as soon as it hit a serious bump on the outback trail, too. So it’s actually not that great for its intended purpose, but it would make an awesome tour bus for Universal Studios.

10 Nissan Pivo 3

It might look like a garish supermini, but actually the Nissan Pivo was a revolutionary small car with four-wheel-steering that can park itself. That’s no big deal these days, we’ve actually got these cars.

But in 2011, when Nissan unveiled this concept, it was something to shout about. Sliding van-style doors open up to give easy access and a car that measures less than 3m long could somehow fit three people inside.

The interior comes with a TFT screen, which again is nothing out of the ordinary now, but it was back then. This was a concept

What’s your favorite? Let us know in the comments!