Among researchers, some "optimists" predict that within the next 30 years almost 99% of earth’s fossil fuel content will be used. This news has certainly created quite a panic in the automobile industry. Scientists are thus compelled to find alternatives to replace oil used in motor cars through means that must be powerful, cheap, and renewable.
In the recent past French engineers were successful in accomplishing the mission by effectively using compressed air for powering vehicles (CATS.)
In the system, light weight tanks made up of composite carbon fiber filled with compressed air are used. The engine of the vehicle is driven by the power of the released compressed air into a second generation flywheel/piston mechanism. The release of the compressed air can be controlled by the driver himself through sophisticated instrumentation.
Once the air pressure inside the tank becomes exhausted, it can be replenished through external electrically charged air compressors. Each filling may provide at least 125 Km of continuous travel for a two-seater vehicle; attempts are being made to further improve this. Here, since no combustion is involved, the entire process becomes highly eco-friendly, silent and with minimum wear and tear.
In some countries compressed air power is also being used in producing electricity in conjunction with the normal methods of utility (Compressed Air Energy Storage CAES Power Plant in McIntosh, Alabama.) Here, during off-peak hours the generated energy is stored in underground mines in the form of compressed air, which is released back to assist in the production of electricity during peak demand hours.
When it comes to the storing of solar and wind power, we normally look toward rechargeable batteries, which can be very effectively used to store the various renewable energy sources by first converting them into electricity. Though more efficient, batteries are not permanent, they degrade fast and ultimately require a replacement, and therefore become a relatively costlier means of power storage. Also as they degrade, their efficiency also declines proportionately.
Contrary to this compressed air energy storage methods look more interesting as these are simpler, uncomplicated, and offer a permanent solution for storing renewable energies.
The procedures involved are simple too; solar heat can be first used to heat water inside an enclosed chamber. The gradual expansion of water will create a high pressure inside the chamber with increasing temperature, and this generated high pressure may be appropriately channelized, transferred, and stored inside high pressure storage tanks.
Similarly wind mills can be easily mechanized to move the piston of an air pump whose resultant output power can be fed and converted into pressurized stored energy inside tanks for future usage.
Dresser-Rand (CAES provider of Alabama installation)