While Nissan and Chevrolet fight it out to become the number one consumer electric vehicle of 2010, six electric vehicle companies most consumers will have never heard of are battling it out to become $10 million richer.

That's the prize fund the winner of the Auto X-Prize could take home in September. The competition's purpose is to inspire a new generation of ultra-fuel efficient vehicles, capable of achieving over 100 miles to the gallon of fuel.

For electric vehicles, that means travelling 100 miles or more on the energy equivalent of one gallon of gasoline.

It's not been easy. After a gruelling two years of competition which has seen a field of 136 vehicles and 111 teams narrowed to just nine vehicles and seven teams, many electric cars have fallen out of the competition.

These teams have included universities, startups, custom car companies and entrepreneurial individuals keen to cash in on the prize fund.



Naturally, many electric cars were entered into the competition, obviously expecting to win over the gasoline powered vehicles which were taking part.

One solitary gasoline powered vehicle remains, the ultra-futuristic, four-wheeled Edison 2,  which resembles an aeroplane without wings.

The remaining competitors are all powered by electricity.

As the competition has progressed, teams have had to prove their vehicle's worth, completing stages designed to test each vehicle's safety, performance, fuel efficiency, handling, range and reliability.

Aside from the Finnish-built Electric Raceabout, a two-seat sports car with ground-hugging stance and the looks of an exclusive price-tag, there are no other vehicles left in the X-Prize which bear any resemblance to the vehicles we drive around in today.

But that's the exact reason behind the Auto X-Prize. The cars we drive today may be more fuel efficient, pollute less and give us unparalleled levels of comfort than the cars we drove ten or twenty years ago, but are in no way as aerodynamic and fuel efficient as they could be.

Aerodynamic designs like those competing at the Auto X-Prize, produce less drag when moving through the air. Drag is caused when any object moves through air, and wastes energy. In vehicles, drag is measured using the drag co-efficient.

Lower the drag co-efficient of a vehicle and less energy is used to push it along.

In turn, efficiency is increased.

Update: Insurance company sponsors 100MPG X Prize challenge

Update: Insurance company sponsors 100MPG X Prize challenge

You can see the futuristic designs of the finalists at the progressive auto x-prize website at www.progressiveautoxprize.org, where you can also follow the teams' progress from the track stages of the competition to the validation stage.

Visitors to the site can also vote for the vehicle they believe to be the most practical of the designs competing. Currently, the TW4XP, a three-wheeled design from Germany is proving to be the most popular among visitors to the site.

While some of the finalists plan to sell their vehicles on a commercial scale in the near future, we're not sure consumers are ready yet for the paradigm shift needed to own and drive such unique vehicles.

However, as Aptera - one of the finalists -  has already found out with its 2e, there are already consumers out there willing to support its take on the humble car.

Even if none of the designs in the final make it to large-scale production we're confident of one thing. The ideas and techniques used to produce vehicles capable of ultra-high efficiency travel could revolutionize the mainstream auto industry, even if the end result is something a little more mundane.