Despite the high cost of powering cargo freighters, it doesn't look like viable alternatives are appearing anytime soon. Instead, the enormous ships  are increasingly turning to innovative ways of lessening fuel consumption. One promising possibility is massive sails—kites really—that can be retrofitted onto ships and aid in propelling them across the ocean. Earlier this month, Beluga Shipping christened its  MV "Beluga SkySails"—a cargo ship with a 520 square foot propulsion kite; the first to utilize the system. A transoceanic voyage  is imminent, but  unfortunately for PPX buyers, the  date has been pushed from mid-December to January.  Most traders guessed correctly, however: The SKYSAIL stock (Will the sail-assisted Beluga freighter depart by December 20, 2007?) was halted at $35.75 and closed at $0.—Abby Seiff

Certain parts of a car’s engine can reach temperatures in excess of 1,500°F. With this in mind, the engineers at BMW developed a way to boost efficiency: Transform that otherwise wasted heat into energy the engine can use. The resulting Turbo- steamer reclaims more than 80 percent of the heat lost from the engine’s exhaust and cooling systems. It uses this surplus heat to generate steam that helps drive the engine. It boosts power and torque by 10 percent and cuts fuel consumption by 15 percent without using a single additional drop of gasoline.