Wednesday, September 16, 2009

Are you Aerovoltaic or Thermovoltaic?

Ideas for conserving energy and tapping into renewable energy sources are all the rage right now as people look for ways to cut their power bills—and help save the planet. With oil reserves dropping, developers and scientists are also in a rush, looking into ways to optimize the use of renewable or alternative forms of energy. From satellites in space down to pedestrians on the street, some green energy ideas are so wacky that—they just might work.

Out of thin air

For over 700 years, people have captured the energy from the wind in only one way: by going around in circles. One of the oldest accounts was from Hammurabi, the Babylonian emperor, who planned to use it in the 17th century BC for his irrigation project, which for the time seemed to be ambitious.

More ambitious are the plans of a Michigan-based startup to develop a new wind energy device that would be able to generate electricity without the moving parts of a wind turbine. The company calls their technology “Aerovoltaic generation” and people are expecting it to be something big.

They claim that their device can harvest electricity at twice the rate per square meter of a photovoltaic solar panel, as stated in the Michigan Business Review. How exactly this works is still under wraps until the release of a prototype next year.

Inspired by nature

Leaves sure are a natural wonder. Plants use it to convert sunlight into energy efficiently to stay alive through photosynthesis. Now scientists are racing to create artificial leaves and trees to power our lives as well.

One of them is London-based Solar Botanic Ltd (SB). Their design uses nano-engineered photovoltaic (PV) leaves that they claim are able to pick up any light, from the visible spectrum to the invisible spectrum, like infrared. The leaf is also made of thermovoltaic materials that enables the leaf to produce electricity even long after the sun has set.

The twigs and branches of the artificial tree are not just for show. Equipped with nano-piezoelectric elements (which produces an electrical charge when stress is applied to them), it produces thousands of picowatts of energy whenever the leaves flap in the wind or rain. A picowatt is one-millionth of a microwatt. The stronger the wind, the more energy the tree can produce.

According to SB, a kilometer can occupy around 70 wind-solar trees which could generate approximately 350,000 kilowatt-hours per year. That is enough electricity to power approximately 60 houses. It also protects the environment by preventing the release of up to 500 tons of CO2 annually.

Revisiting manpower

Vibrations from passing trucks, the rumbling of speeding trains and even the footfall of trudging commuters in a busy city are often seen as an urban nuisance. But a London-based architectural firm says that opportunity lies in the urban jungle.

Facility:Innovate, a sister company of The Facility, says that movement associated with footsteps or transport vibration could be captured and converted into electricity. To capture heel-power from pedestrians, floors are wired with hydraulic compression cushions. Every footstep pushes fluid through a micro-turbine, generating power that is stored in a super-capacitor.

Conversely, vibrations caused by crisscrossing vehicles could be harvested to power light fittings by using a magnetic beam and a coil arrangement. The beam vibrates in tune with the ambient vibration within the generating coil. This electricity is then used to power the LED installed.

The BBC said the Victoria underground station in central London was estimated to have 34,000 travelers passing through every hour which could power 6,500 light bulbs using the technology.

Space: Energy’s next frontier?

Some researchers think the an¬swer to our energy needs rests in the stars. Even if solar power is at our fingertips, scientists see benefits in looking up, literally, for inspiration. Aside from the more obvious reason of avoiding the large land-use footprint of most solar arrays, the sun actually does shine brighter in space. In this case, five times as much powerful.

PowerSat, based in Washington, is one such company that pioneers in space solar power introduced by American scientist Peter Glaser in 1968. It works by sending solar power satellites, called Powersat, clustered into groups of 300 keeping pace with the earth’s orbit. Each Powersat satellite is made up light weight PV solar panels that are as thin as aluminum foil and are printed on one-micron-thin titanium.

Electricity is beamed down to earth via wireless power transmission. Hundreds of smaller satellites could team up to produce a very powerful transmission signal. The receiving station collects the power, which is then fed into a conditioning station and put directly onto the local power grid.

Unlike other sources of renewable energy, space solar power is not limited by geography, climate or even time of day being able to produce clean grid-quality electricity 24/7. The company says that Powersats are comparable to very large ground based energy plants in that they will produce a minimum of 2,500 megawatts (MW).

PowerSat Corporation estimates roughly US $3-4 billion for a 2,500 MW plant. This fares better than expensive large hydro projects or nuclear power plants of the same capacity. PowerSat said it is expecting to transmit power to commercial customers in 10-12 years.

In the end, while the sources of energy might be finite, the human capacity for innovation is not. We can hope that some of these innovations can actually work.

from Ecoseed

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