hybrid

An electric Humvee may still sound like fingernails on a chalkboard to environmentalists, but the company developing a plug-in Hummer H3e claims its green version can get 100 mpg on average. And what's a little boasting without taking a shot at the competition?

We've told you about bike-sharing programs before, but the Hybrid2 design by Chiyu Chen takes the idea one step further, by using the bikes to put power back in the system. The idea is to put "ultracapacitors" into the bikes that will harness and store the kinetic energy generated by pedaling and braking. Once you return the bike to its rental kiosk, the energy stored in the bike will be transferred to the city's smart grid, and used to help power hybrid buses.

It fits into a wheel hub and can double a car's fuel economy. That's the claim of Dr. Charles Perry, who says his plug-in hybrid retrofit kit can save America 120 million gallons of fuel per day. Big talk. But then, inventors betting on revolutionary uphevals need to talk as big as they think. The former IBM electrical engineer designed the kit to transform existing automobiles into hybrids by placing an electric motor inside each wheel. Perry recently took first prize for his invention at a green energy competition at the Tennessee Technology Development Corp.

Hybrid cars may be a favorite among commuters looking to save fuel, but they're yet to appear on a single driving enthusiast's bucket list. It's no secret why: A 2009 Prius gets from zero to 60 mph barely faster than a plumber's van.

How do you make hybrid cars a little rougher on the adrenal glands without sacrificing the good fuel economy and low emissions? Engineers at Austrian tech firm AVL took a page from the motorsports playbook, using a turbocharger to boost the performance of a standard gas-electric hybrid.

Gas is cheap now, but everyone who remembers when it was $4 a gallon knows it won't be affordable forever - especially when world demand exceeds supply. (In 2007, the usually staid International Energy Agency predicted the world supply of oil could peak before the average consumer has ditched their current vehicle.) Meanwhile, the same economic crisis that sent oil futures into a tailspin has made belt-tightening more important than ever.

The MP3 500 hybrid is Piaggio's answer to all that.

Imagine a car veering off a lonely mountain road and tumbling down the embankment. Minutes later, a sleek aircraft zooms in quietly at 230 miles an hour, tilts its wings and rotors up, hovers, and sets down just feet from the wreck. The pilot and a medic load the injured driver into the aircraft and zip back to a hospital at twice the speed of a conventional helicopter ambulance.

Earlier this month, Japanese media reported Honda and Yamaha were each planning a line of electric motorcycles by 2010. The new bikes, which reports say can travel up to 60 miles on a charge, will use lithium-ion batteries for power. Now, word from Japan's Mainichi news service is Honda is also planning new gas-electric hybrid motorcycles.

The small airplane is too dirty for an environmentally threatened world. Thats not the view from eco-activists, but from some of the leading lights in general aviation—the category encompassing small planes such as Cessnas flown by citizen pilots. At some point, some environmental group is going to figure out that small aircraft fly leaded fuel, said Mark Moore, NASAs personal air vehicle program manager, to a meeting of engineers, aviation advocates and a billionaire corporate titan with his own private jet. Their goal, however, is not to bury private aviation, but to remake it as the greenest form of personal transit.

For more on the Civic GX's natural-gas powertrain and the innovative home-fueling station that keeps it going at a fraction of the cost of gasoline, launch the slideshow.

Behold the car that could displace the Toyota Prius as the eco-ride of choice. The new natural-gas-powered Honda Civic GX uses domestically produced fuel–the same stuff your gas stove burns–that costs as little as one third the price of gasoline. The American Council for an Energy-Efficient Economy calls it the cleanest-burning internal-combustion vehicle on Earth.