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Cages with sensors would travel the ocean using solar power

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Innovations: Robotic Fish Farms and Trees as Fire Sentinels

Floating fish farms are easier to tend when constructed in sheltered waters. But that means waste accumulates and breeds diseases, despite the motion of waves. So farmers tow the pens to new locations—thus burning fuel and creating more pollution.

Now, in waters off Puerto Rico, researchers from Massachusetts Institute of Technology working with Snapperfarm, a U.S. fish producer, are testing a self-propelled spherical fish cage made by Ocean Farm Technologies. About 20 yards wide, the fully submerged cage is designed to migrate from place to place using slow-moving propellers.

In the future, says Cliff Goudey, director of MIT's Offshore Aquaculture Engineering Center, the cages would be tied to floating platforms bearing lights, positional sensors, and monitoring gear—all powered by wave motion or solar cells. Such systems would be almost autonomous, though people would still have to replace the feed. Stocked with baby fish and launched from Panama, say, the farm would follow the Gulf Stream and show up months later near Miami when the fish are ready to harvest. Lockheed Martin may build remote management systems for such farms.

—Edited by Adam Aston

Electric Cars: Where to Plug In Away From Home?

Plug-in electric vehicles have an edge over hydrogen-powered cars for a simple reason: The infrastructure to support them, the electric grid, is already in place. At night, you just connect the car to an outlet in your garage.

Unless of course, you don't have a garage. Now, Coulomb Technologies of Campbell, Calif., wants to provide service to city-dwellers and other drivers who lack handy access to an outlet for their cars. It's testing a subscription-based network in San Jose called ChargePoint, whose members use special key fobs to access outlets mounted on lamp posts, parking meters, or in parking lots. The power isn't free. Subscribers must register a credit card when they sign up for the service. Then, when they swipe the key fob, their usage is metered and charged to the card.

China is taking a different, top-down approach. It's starting to build a nationwide network of charging points to speed the adoption of electric vehicles. Electricité de France is working with carmakers on a similar idea.

—By David Kiley, Edited by Adam Aston

Solyndra's New Solar Collector Is a Tube

Tubes may soon start to replace familiar rectangular panels in rooftop solar systems. A design by Solyndra, a Fremont (Calif.) startup, arranges rows of cylinders, each about the size of a standard fluorescent light. The approach promises to save money. With today's panel systems, each tile-shaped collector is anchored to custom racks—tilted to face the sun—which in turn are connected to the roof. That keeps them secure in high winds.

Solyndra's tubes don't require custom mountings, and gusts of wind pass right through without causing damage. Also, the tubes collect rays from every angle as the sun crosses the sky, and they even capture reflected light from below. Compared with heavier tiles, more of the lightweight tubes can fit on a roof, boosting output by 25%.

Solyndra's lower installation costs have attracted venture capital firms like Richard Branson's Virgin Green Fund and Madrone Capital, an investment arm of Wal-Mart's Walton family, which have pledged $600 million.

—Edited by Adam Aston