Tavrima Canada Ltd. - Largest and most powerful supercapacitors. New energy storage technology suited for uses needing repeated bursts of power for fractions of a second to several minutes.

Physical Limits of Portable Power Storage - MIT Media Lab study on 4 options: flywheels, compressed air, ultracapacitors, fuel cells.

Zero Pollution Motors, Inc. - Clean vehicles with compressed air motors; use high pressure 300 bar compressed air to store energy needed to run the engine; 120/200 mi/km range; very quiet. Naturally, they also have a new type of internal combustion engine, for more range.