Weird Ways to Harness Sun Power

Following are seven potential sources for next-generation solar power:

Hot roads and parking lots. All those roadways and parking lots shimmering with heat on sunny days could do more than turn your car into a sauna, according to researchers at the Massachusetts-based Worcester Polytechnic Institute. Areas paved with asphalt could heat up water in buried pipes, providing a ready source of power across the landscape, researchers say. The hot water could be used to heat buildings or could be run through a thermoelectric generator to produce electricity. Such systems could even offer a few advantages over traditional rooftop arrays, the researchers say. One, the pipes would be under roads or parking lots, so they'd be invisible to the public. Two, they'd reduce the "heat island" effect that can make paved urban areas so uncomfortable on hot summer days. And three, they could continue generating energy even after sunset, thanks to asphalt's heat-absorbing powers.

"Our preliminary results provide a promising proof of concept for what could be a very important future source of renewable, pollution-free energy for our nation," said Rajib Mallick, associate professor of civil and environmental engineering. "And it has been there all along, right under our feet."

Infrared-gathering nanoantennas. Researchers are eyeing plastic sheets embedded with billions of super-microscopic "nanoantennas" as a way to harness the power of the sun and more. The nanoantennas collect infrared radiation -- better known to us as heat -- rather than visible sunlight, which means they could generate energy around the clock, sopping up both ambient heat and waste heat from buildings and electronic devices. The concept is still a long way from becoming a mass-market reality, but it's an idea with huge potential.

"Every process in our industrial world creates waste heat," said Steven Novack, a physicist with the US Department of Energy's Idaho National Laboratory. And right now, he added, "It's energy that we just throw away."

Water-powered dryers. Among the innovations being tested by students and faculty at the University of Cinncinati's (UC) solar house is a solar-heated dryer closet. Clothes hung in the enclosed closet are dried by hot air rising from pipes at the bottom, which carry water heated by the sun. Even more promising: an adaptor that could enable homeowners to use the heat from water to power a conventional clothes dryer.

"Use of this adapter would represent a significant cost and energy savings annually and over the life of the dryer," said Anton Harfmann, an associate dean at UC's College of Design, Architecture, Art and Planning. "One day, we'd love it if conventional dryers could be sold with our idea as a simple modification kit,"

Solar-powered bicycle kiosks.Freewheelin, a new national bike-sharing program, lets users check out free bicycles using solar-powered kiosks. The program, developed by Humana Inc. and the cycling group Bikes Belong, is getting a major debut at this summer's Democratic and Republican national conventions in Denver and Minneapolis-St. Paul.

Light-generating tree "leaves." What a neat concept is this: lighting nighttime pathways with solar-powered, leaf-shaped lights wound around street-side tree branches? Created by South Korean designer Jongoh Lee, the "Invisible Streetlights" are actually solar-powered LED lamps shaped like leaves and easily attached to trees in any quantity.

Solar-charged fuel cells. Tapping the sun's power today carries several disadvantages: you can't do it in the dark, and it's hard (and expensive) to efficiently store solar-generated energy for use when the sun isn't shining. But researchers at the Massachusetts Institute of Technology (MIT) believe they might have found a solution to those drawbacks. Building on the concept of photosynthesis that plants use to tap the sun's power, MIT researchers have developed a way to use solar energy to split water into its components, hydrogen and oxygen. When those two gases are recombined in a fuel cell, they release energy that can be used to generate clean electricity, day or night.

"This is the nirvana of what we've been talking about for years," said MIT researcher Daniel Nocera. "Solar power has always been a limited, far-off solution. Now we can seriously think about solar power as unlimited and soon."

Window power. Rather than relying on large and very noticeable solar panels on their roofs, homeowners could one day invisibly tap the sun's power through their windows. Another development by researchers at MIT, window-based solar power would use dye-based solar concentrators on the glass to focus the sun's energy onto photovoltaic cells at the window's edges. Better still, researchers say, the system is simple enough that it could become widely manufactured and available within three years or so.