LONDON , England ( CNN ) -- Hydrogen and electric vehicles might be leading the charge , so to speak , towards cleaner transport , but will cars powered by air and the sun ever surpass the sales figures of gasoline cars ? MDI boss Guy Negre with his AirPods which start a six-month trial at two European airports in 2009 . Click here to read about the latest hydrogen and electric cars . A BREATH OF FRESH AIR . It might seem ridiculous , but air -- yes , air -- can power a car . Compressed air , stored in a carbon-fiber tank and then released , expands to drive the engine 's pistons in the same way that petrol gases do . A Luxembourg-based company , Motor Development International ( MDI ) is at the forefront of the air car 's push to market . Former Formula 1 engineer and MDI founder Guy Negre has been working on the technology for almost two decades and is producing a fleet of different models including the OneCAT , the CityCAT and the AirPod . India 's biggest car maker , Tata Motors , and a U.S. startup , Zero Pollution Motors , have both signed deals with MDI and hope to have air cars on the road by 2010 . In the U.S. the starting price will be nearly $ 18,000 . In October 2008 , Air France and the Dutch airline KLM announced that they will be testing out MDI 's `` AirPods '' for six months starting in spring 2009 . The four seaters will ferry passengers around Charles De Gaulle Airport in Paris and Schiphol Airport in Amsterdam . MDI says one tank of compressed air will take you about 60 miles in the OneCAT , which has a top speed of 35 miles per hour . As you 'd expect from a car that runs on air , there is zero pollution . VERDICT . Compressed-air engines are not new technology -- the French were powering trams with compressed air back in the 19th century . But the air car is highly unlikely to surpass the gasoline car and does n't have enough oomph to seriously challenge new electric and fuel-cell vehicles . Malcolm McCulloch , an electrical engineer from the UK 's Oxford University , says : `` They are interesting , but the problem is that the specific energy -- energy per unit mass -- is very high in air cars . '' Professor Paul Shayler from the School of Mechanical , Materials and Manufacturing Engineering at the UK 's University of Nottingham says : `` It 's an idea that 's worth pursuing , but compressing air is both a strength and a weakness . The big advantage of conventional engines is that you can put fuel with a high energy content in a tank and get good range . With a compressed air engine the range is not spectacular . '' SOLAR SYSTEMS . Solar cars harvest sunlight to drive an on-board electric motor . You 're probably familiar with the solar cars that look a bit like a stingray on wheels , but those are n't commercially viable and are mostly entered into endurance races like the annual World Solar Challenge in Australia . A French motor company , Venturi , has produced an electro-solar hybrid . The Eclectic Concept -- a car with roof-mounted solar panels which power an electric motor -- was so popular , Venturi says , that they have adapted it into a commercial model . The Eclectic is yours to own for $ 30,000 and uses solar panels to collect energy to power an electric engine . It has a range of about 30 miles and has a top speed of 30 mph . The car is featured in the 2008 movie , `` Babylon A.D. , '' starring Vin Diesel . It is rumored that the Toyota Prius -- which passed the one million worldwide sales mark in 2008 -- has a new model due out next year that will be fitted with solar panels on its roof to power the car 's air conditioning . VERDICT . Venturi has demonstrated that it is perfectly possible to produce solar powered vehicles . But they are expensive when you consider the level of performance they can deliver . Professor Shayler says : `` Solar power has a long way to go . At the moment you simply do n't have the energy density to do anything special . '' But McCulloch thinks that solar could assist the growth of electric cars . `` Your garage could have solar panels on its roof , store up energy during the day and charge your vehicle at night , '' he said . `` And parking lots and the like could be fitted with solar panels . So there are ways that those two can play together . '' THE FUTURE . John Turner , Research Fellow at the National Renewable Energy Laboratory in Colorado , says : `` We are talking about a new paradigm here because we know the old paradigm is going to go away . `` For hydrogen , or any new fuel for that matter , to succeed there has to be a policy decision . At the moment it 's not cost effective and it 's not going to be cost effective until we get into the tens of millions of units per year . There is no way of getting around this . Politicians have to decide when they want to put a policy in place . It 's not an economic decision , it 's a policy decision . '' But any major changes are going to take a long time , he says . `` The issue is manufacturing . Last year we made 60 million cars worldwide . That 's two cars a second . That 's the current level of production . It has taken many years to get up to that rate , '' Turner said . Click here to read about hydrogen and electric vehicles .
Is the gas engine about to be overtaken by a host of cleaner , leaner rivals ? Cars running on air are expected to be on sale in the U.S. and India by 2010 . French motor company has developed a solar car roof that powers an electric motor .