Green Transportation: Compressed Air Vehicles

by Chuck Hall

Way back in the 19^th century, novelist Jules Verne predicted that cars of the future would run on compressed air. Well, the future is here! Motor Development International (MDI) has developed just such a vehicle (www.theaircar.com). If you drive less than fifty miles per day at less than forty miles per hour, these inexpensive vehicles may just be the green alternative for you. The current prototypes, the MiniCAT and the CityCAT, both run on compressed air. The CityCAT will have a longer range than the MiniCAT, but the operating principle is still the same: a tank of compressed air runs a two-cylinder engine that propels the vehicle. The MiniCAT has a maximum range of about 120 miles and a maximum speed of 40 mph. It runs exclusively on a compressed air tank that may be refueled in about three minutes at any station that has a high-capacity air compressor. It may alternatively be refilled by using the car’s onboard compressor, which runs on electricity and may be plugged into any standard outlet. Using this method requires about four hours for a recharge.

The CityCAT is a duel-energy vehicle. It runs on compressed air for short trips under 60 mph, and when more power and longer range are needed, it can be  run on its internal combustion engine. It has a maximum speed in excess of 100 mph and a range of approximately 200-250 miles before refueling. While either of these cars is a bit small for the entire family, they are perfect commuter cars for urban travel.

Either model produces zero pollution when operating in compressed air mode; however, the CityCAT has the same emissions problems as any other internal combustion engine when running on gasoline. The slight advantage here is that since it is a smaller car than most standard production cars on the market today, it would presumably use less fuel and therefore generate less pollution. There is another precaution to consider with CAT vehicles. Whether recharging the tank by plugging into a convenient outlet or by a commercial compressor, the electricity used would have to come from a green energy provider in order for the car to be truly non-polluting. If the electricity used to recharge the tank is coming from a power plant that burns fossil fuels, the pollution is just being transferred up the supply chain. The simple solution to this would of course be to purchase your electricity from a green power facility.

The current projected price for these vehicles is surprisingly inexpensive, at around $7000 to $10,000 each. When compared with the cost of hybrids and other alternative energy vehicles, these minis appear to be an amazingly good value for your transportation dollar.

After several false starts, MDI has cautiously estimated that both the MiniCAT and the CityCAT will be commercially available sometime in 2009. They are currently undergoing a lengthy licensing process to make the vehicles available to the general public worldwide. To chart the progress of the air car, you may visit MDI’s Web site at www.theaircar.com.