Sunday 15 September 2013

Nuclear power’s renaissance in reverse
9 May 2013

PARIS-Last June, Yukiya Amano, the director general of the International Atomic Energy Agency (IAEA), declared that "nuclear power will make a significant and growing contribution to sustainable development in the coming decades". But, as this year's World Nuclear Industry Status Report highlights, recent trends paint a very different picture.

Duke Energy, America's largest utility, has shelved plans to build two reactors in Florida, after having spent $1 billion on the project. The decision came only three months after the company abandoned investment in two new units in North Carolina.

In fact, this year, four American utilities have decided to shut down a total of five reactors permanently-the first closures in the United States in 15 years. One of the units-Kewaunee Power Station in Wisconsin-was abandoned after massive investment in upgrades and a 60 year license renewal; it simply could not generate power at competitive prices. For the same reasons, Vermont Yankee, another plant with a license to operate through 2032, is now scheduled to close in 2014.

Similarly, the world's largest nuclear operator-the French state-controlled utility Electricite de France-announced its impending withdrawal from nuclear power in the US, after having sunk roughly $2 billion into aborted projects. And, in order to help offset soaring operating costs, which resulted in losses of €1.5 billion ($2 billion) last year, EDF Energy will raise electricity prices this year for its French customers by 5%, on average, and by another 5% next year.

Over the five years ending in March 2013, EDF Energy lost 85% of its share value. Likewise, the world's largest nuclear builder-the French state-controlled company AREVA-lost up to 88% of its share value between 2008 and 2012. Not surprisingly, investors have welcomed new strategic plans by both companies, as well as EDF Energy's withdrawal from the US market; the downward pressure on their share prices has eased, though for how long remains to be seen.

The nuclear power industry's decline began decades ago. But, since the March 2011 triple-meltdown at Japan's Fukushima Daiichi plant, the pace of the decline has accelerated significantly. Indeed, in 2012, annual nuclear generation worldwide dropped by an unprecedented 7%, exceeding the previous year's record-breaking drop of 4% and bringing total annual nuclear power generation to 12% below its historic maximum, achieved in 2006.

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Alstom signs 27MW Brazilian wind turbine deal
5 Sep 2013

BRAZIL: Alstom has signed a EUR 25 million contract with Enerplan, a subsidiary of Brazilian power company Oleoplan, to supply 27MW to a project southern Brazil. The company will supply 10 ECO 122 low wind turbines to the Pontal wind farm Viamao, Rio Grande do Sul state, and is scheduled to be commissioned by the end of 2015.

The nacelles will be manufactured at Alstom's plant in Bahia state and the towers will be produced at the company's new facility in Canoas, in Rio Grande do Sul state. Alstom is responsible for the operation and maintenance of the wind turbines for five years. Since 2010 Alstom has provided more than 2GW in wind projects in Brazil, including the supply of more than 600 ECO 122 wind turbines.

CLP Holdings says talks discontinued in China nuclear plant bid
4 Sep 2013

Talks have been discontinued for Hong Kong electricity producer CLP Group Ltd. (2) to buy a 4.8 billion ¥ ($784 million) stake in a Chinese power plant following regulatory delays after Japan's nuclear crisis.

Shareholder China General Nuclear Power Corp, told CLP Group this week that the deal wouldn't go ahead "for the time being", CLP Group said in a Hong Kong stock exchange filing yesterday. CLP Group agreed in 2011 to buy the 17% stake in the Yangjiang Nuclear Power Station in southern China's Guangdong province.

"Discussions on Yangjiang have been discontinued", CLP Group said in yesterday's statement. "There is no assurance that discussions will recommence or, if they do, that CLP Group will then be able to reach agreement".

The announcement upsets CLP Group's plans to increase spending on nuclear power even after the Fukushima Dai-Ichi nuclear crisis prompted China to halt approval of new projects. Construction of the 6,000 MW Yangjiang plant, which was due to start operating in phases from 2013 to 2017, was delayed as the nation reviewed nuclear safety.

China General Nuclear Power said CLP Group wouldn't be able to take up the stake following the delays as well as a review of "funding needs and capital raising options", according to the CLP Group statement.

Shedding new light on the 'electron highways' of organic solar cells
2 Sep 2013

( absorbed by organic solar cells must first navigate a nanoscale gauntlet before becoming useable electricity. After hitting the light-absorbing material of the solar cell, called the photoactive layer, absorbed sunlight excites electrons, freeing them to find their way through a maze filled with twists, turns, dead-ends, and collisions. Only the free charges that successfully make it through this maze can be used in a circuit as electricity. So scientists have been looking for ways to ease the electron traffic jam in organic photovoltaics.

Now, researchers at the US Department of Energy's (DOE) Brookhaven National Laboratory and Stony Brook University have developed a way to map out the degree of "traffic congestion" on the electron highways within the photoactive layer. Their new measurement and tracking technique uses optical-guided modes--a process of guiding light through precise areas in the horizontal plane of solar cells--to help scientists better understand how the materials used in the photoactive layers influence the speed and efficiency of electron travel.

"With our technique, you can now better understand how far the electrons move through the complex network of the photoactive layer", said Brookhaven physicist Matthew Eisaman, team leader on the new study published online in Advanced Energy Materials on August 25, 2013. "Previous studies revealed the material composition, but our technique illuminates how that structure impacts electron transport".

Unlike the large silicon-based solar cells you might typically see on household roofs or arrayed in large-scale installations to generate electricity, organic solar cells are more like flexible plastics. Organic cells could find widespread applications in portable power generation for commercial and military use or even in so-called "building-integrated photovoltaics", where solar cells are directly integrated into the windows, facade, or roof of a building. Their flexible forms can be made inexpensively using large-scale, roll-to-roll manufacturing. But for now these versatile materials are not as efficient as inorganic options.

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New nanomaterial increases yield of solar cells
26 Aug 2013

Researchers from the FOM Foundation, Delft University of Technology, Toyota Motor Europe and the University of California have developed a nanostructure with which they can make solar cells highly efficient. The researchers published their findings on 23 August 2013 in the online edition of Nature Communications.

Smart nanostructures can increase the yield of solar cells. An international team of researchers including physicists from the FOM Foundation, Delft University of Technology and Toyota, have now optimised the nanostructures so that the solar cell provides more electricity and loses less energy in the form of heat.

Solar cells
A conventional solar cell contains a layer of silicon. When sunlight falls on this layer, electrons in the silicon absorb the energy of the light particles (photons). Using this energy the electrons jump across a 'band gap', as a result of which they can freely move and electricity flows.

The yield of a solar cell is optimised if the photon energy is equal to the band gap of silicon. Sunlight, however, contains many photons with energies greater than the band gap. The excess energy is lost as heat, which limits the yield of a conventional solar cell.

Several years ago the researchers from Delft University of Technology, as well as other physicists, demonstrated that the excess energy could still be put to good use. In small spheres of a semiconducting material the excess energy enables extra electrons to jump across the band gap. These nanospheres, the so-called quantum dots, have a diameter of just one ten thousandth of a human hair.

If a light particle enables an electron in a quantum dot to cross the band gap, the electron moves around in the dot. That ensures that the electron collides with other electrons that subsequently jump across the band gap as well. As a result of this process a single photon can mobilise several electrons thereby multiplying the amount of current produced.

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