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Electricity | Green and Alternative Energy Information

Efficient, inexpensive plastic solar cells coming soon

ScienceDaily (Oct. 11, 2010)  Physicists at Rutgers University have discovered new properties in a material that could result in efficient and inexpensive plastic solar cells for pollution-free electricity production.

The discovery, posted online and slated for publication in an upcoming issue of the journal Nature Materials, reveals that energy-carrying particles generated by packets of light can travel on the order of a thousand times farther in organic (carbon-based) semiconductors than scientists previously observed. This boosts scientists’ hopes that solar cells based on this budding technology may one day overtake silicon solar cells in cost and performance, thereby increasing the practicality of solar-generated electricity as an alternate energy source to fossil fuels.

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Converting Waste Heat to Electricity

With rapid industrialization, the world has seen the development of a number of items or units, which generate heat. Until now this heat has often been treated as a waste, making people wonder if this enormous heat being generated can be transformed into a source of electric power. Now, with the physicists at the University of Arizona finding new ways to harvest energy through heat, this dream is actually going to become a reality.

University of Arizona Research Team: The research team is headed by Charles Staffor. He is the associate professor of physics, and he along with his team worked on harvesting energy from waste. The team’s findings were published in the September 2010 issue of the scientific journal, ACS Nano.

Justin Bergfield who is an author and a doctoral candidate in the UA College of Optical Sciences shares his opinion, “Thermoelectricity can convert heat directly into electric energy in a device with no moving parts. Our colleagues in the field tell us that they are confident that the device we have designed on the computer can be built with the characteristics that we see in our simulations.”

Advantages: Elimination of Ozone Depleting materials: Using the waste heat as a form of electric power has multiple advantages. Whereas on one hand, using the theoretical model of molecular thermoelectric helps in increasing the efficiency of cars, power plants factories and solar panels, on the other hand efficient thermoelectric materials make ozone-depleting chlorofluorocarbons, or CFCs, outdated.

More Efficient Design: The head of the research team Charles Stafford is hopeful about positive results because he expects that the thermoelectric voltage using their design will be 100 times more than what others have achieved. If the design of the team, which they have made on a computer does work, it will be a dream come true for all those engineers, who wanted to catch and make use of energy lost through waste but do not have the required efficient and economical devices to do so.

No need for Mechanics: The heat-conversion device invented by Bergfield and Stafford do not require any kind of machines or ozone-depleting chemicals, as was the case with refrigerators and steam turbines, which were earlier used to convert waste into electric energy. Now, the same work is done by sandwiching a rubber-like polymer between two metals, which acts like an electrode. The thermoelectric devices are self-contained, need no moving parts and are easy to manufacture and maintain.

Utilization Of Waste Energy: Energy is harvested in many ways using the car and factory waste. Car and factory waste can be used for generating electricity by coating exhaust pipes with a thin material, which is a millionth time of an inch. Physicists also take advantage of the law of quantum physics, which though not used often enough, gives great results when it comes to generating power from the waste.

Advantage Over Solar Energy: Molecular thermoelectric devices may help in harvesting energy from the sun and reduce the dependence on photovoltic cells, whose efficiency in harvesting solar energy is going down.
How It Works

Though having worked on the molecule and thinking about using them for a thermoelectric device, Bergfield and Stafford had not found anything special till an undergraduate discovered that these molecules had special features. A large number of molecules were then sandwiched between electrodes and exposed to a stimulated heat source. The flow of electrons along the molecule was split in two once it encounters a benzene ring, with one flow of electrons following along each arm of the ring.

The benzene ring circuit was designed in such a way that the electron travels longer distance round the rings in one path, which causes the two electrons to be out of phase when they reach the other side of the benzene ring. The waves cancel out each-other on meeting. The interruption caused in the flow of electric charge due to varied temperature builds up voltage between electrodes.

The effects seen on molecules are not unique because any quantum scale device having cancellation of electric charge will show a similar effect if there is a temperature difference. With the increase in temperature difference, energy generated also increases.

Thermoelectric devices designed by Bergfield and Stafford can generate power that can lit a 100 Watt bulb or increase car’s efficiency by 25%.

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Less Power To Refrigerators! Appliances Get More Efficient From 2014

Via Conservrefrigerators.com

The U.S. Department of Energy (DOE) this week announced new efficiency standards for most new refrigerators as of 2014. Energy efficiency for these domestic appliances is set to increase by 25%. They account for about 10% of household electricity use.

Advocacy groups and appliance manufacturers welcomed the news. “We appreciate that DOE has moved so quickly to adopt the agreed-upon standards,” said Andrew deLaski, Executive Director of the Appliance Standards Awareness Project (ASAP). “The consensus standards not only save consumers a huge amount of energy and money, they also save DOE the energy, time, and money that a contentious rulemaking process can require.”

According to the proposed rule, a typical new 20-cubic-foot refrigerator with the freezer on top would use about 390 kilowatt hours (kWh) per year, down from about 900 kWh/year in 1990 and about 1,700 kWh/year in the early 1970s. On a national basis, the new standards would, over 30 years, save 4.5 quads of energy, or roughly enough to meet the total energy needs of one-fifth of all U.S. households for a year. Over the same period, the standards will save consumers about $18.5 billion. DOE will finalize the standards by year’s end, and they take effect in 2014.

“The appliance industry has a strong history in reaching agreement with a broad base of energy and water efficiency advocates, as well as consumer groups, to develop energy conservation standards for home appliances,” said Joseph McGuire, President of the Association of Home Appliance Manufacturers. “The new minimum energy standards are a significant part of the agreement, as is the extension of the current super-efficient manufacturers’ tax credits, which we are urging Congress to act on, and a soon-to-be-submitted petition to ENERGY STAR on smart appliances.”

Based on the July agreement, home appliance manufacturers and efficiency, environmental and consumer advocates have agreed to jointly pursue with Congress and the Administration new standards for six categories of home appliances (refrigerators, freezers, clothes washers, clothes dryers, dishwashers and room air conditioners), a recommendation that ENERGY STAR qualification criteria incorporate credit for Smart Grid capability, and a package of targeted tax credits aimed at fostering the market for super-efficient appliances.

As part of the new refrigerator standards, ice maker energy consumption also will be reflected in product energy-use ratings to help consumers gauge actual energy use choosing a refrigerator.

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Mimicking nature, water-based ‘artificial leaf’ produces electricity

A team led by a North Carolina State University researcher has shown that water-gel-based solar devices — “artificial leaves” — can act like solar cells to produce electricity. The findings prove the concept for making solar cells that more closely mimic nature. They also have the potential to be less expensive and more environmentally friendly than the current standard-bearer: silicon-based solar cells.

The bendable devices are composed of water-based gel infused with light-sensitive molecules — the researchers used plant chlorophyll in one of the experiments — coupled with electrodes coated by carbon materials, such as carbon nanotubes or graphite. The light-sensitive molecules get “excited” by the sun’s rays to produce electricity, similar to plant molecules that get excited to synthesize sugars in order to grow, says NC State’s Dr. Orlin Velev, Invista Professor of Chemical and Biomolecular Engineering and the lead author of a paper published online in the Journal of Materials Chemistry describing this new generation of solar cells.

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Selling the electricity you generate

The feed-in tariff has made it simpler to sell the electricity you generate, but don’t use in the house, back to the grid. It has set standard rates to be paid for electricity generated which are dependent on type of technology and size of system, and all exported electricity is paid at 3p per kWh.

Choosing your energy supplier is the key to selling excess. The reason it is simpler now is that under the previous system all the suppliers offered different buy back rates, and these had to be weighed up against the rates at which they sell electricity, so it was complex to work out the best deal.

Now all the big energy companies must buy back exported electricity from microgeneration, and some of the smaller ones have chosen to. If price is your key factor, then there’s no shortage of price comparison sites available.

If it’s important to you that the electricity you buy from the grid is from renewable sources you can use our guide How to buy renewable electricity.

 

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