Solar, Wind, and Fire

Solar, Wind, and Fire

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All Things Solar
Text Box: Cornell University (2010, July 4). Molecules found in blue jean and ink dyes may lead to more efficient solar cells. ScienceDaily. Cornell University researchers have discovered a simple process -- employing molecules typically used in blue jean and ink dyes -- for building an organic framework that could lead to economical, flexible and versatile solar cells. The discovery is reported in the journal Nature Chemistry. Today's heavy silicon panels are effective, but they can also be expensive and unwieldy. Searching for alternatives, William Dichtel, assistant professor of chemistry and chemical biology, and Eric L. Spitler, a National Science Foundation American Competitiveness in Chemistry Postdoctoral Fellow at Cornell, employed a strategy that uses organic dye molecules assembled into a structure known as a covalent organic framework (COF). Organic materials have long been recognized as having potential to create thin, flexible and low-cost photovoltaic devices, but it has been proven difficult to organize their component molecules reliably into ordered structures likely to maximize device performance. "We had to develop a completely new way of making the materials in general," Dichtel said. The strategy uses a simple acid catalyst and relatively stable molecules called protected catechols to assemble key organic molecules into a neatly ordered two-dimensional sheet. These sheets stack on top of one another to form a lattice that provides pathways for charge to move through the material. The reaction is also reversible, allowing for errors in the process to be undone and corrected. "The whole system is constantly forming wrong structures alongside the correct one," Dichtel said, "but the correct structure is the most stable, so eventually, the more perfect structures end up dominating." The result is a structure with high surface area that maintains its precise and predictable molecular ordering over large areas. The researchers used x-ray diffraction to confirm the material's molecular structure and surface area measurements to determine its porosity. At the core of the framework are molecules called phthalocyanines, a class of common industrial dyes used in products from blue jeans to ink pens. Phthalocyanines are also closely related in structure to chlorophyll, the compound in plants that absorbs sunlight for photosynthesis. The compounds absorb almost the entire solar spectrum -- a rare property for a single organic material. "For most organic materials used for electronics, there's a combination of some design to get the materials to perform well enough, and there's a little bit of an element of luck," Dichtel said. "We're trying to remove as much of that element of luck as we can." The structure by itself is not a solar cell yet, but it is a model that will significantly broaden the scope of materials that can be used in COFs, Dichtel said. "We also hope to take advantage of their structural precision to answer fundamental scientific questions about moving electrons through organic materials." Once the framework is assembled, the pores between the molecular latticework could potentially be filled with another organic material to form a light, flexible, highly efficient and easy-

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Text Box: Wind energy: with more than 74 GW of total installed capacity in 2009, it has already exceeded the 2010 white paper target of 40 GW by more than 80%. The European Wind Association's new target aims for 230 GW of installed capacity (40 GW offshore) by 2020, capable of providing about 20% of Europe's electricity demand. Biomass: if current growth continues, electricity output from biomass could double from 2008 to 2010 (from 108 TWh to 200 TWh). However, other energy uses such as heat and transport fuels compete for this particular source, which could potentially hinder the development of bioelectricity. Being storable for use on demand increases its importance as a source of electricity. Concentrated Solar Power (CSP): installed capacity is still relatively small in Europe: 0.430 GW in May 2010, about 0.5% of the total, but is steadily increasing. An estimated 30 GW could be installed by 2020 if the European Solar Industry Initiative ESII is realized. Most CSP projects currently under construction are located in Spain. Solar Photovoltaic: since 2003, the total installed capacity has doubled each year. In 2009 it reached 16 GW, which represents 2% of the overall capacity. The growth will continue, as for 2010, installations of up to 10 GW are expected. Solar photovoltaic has also exceeded the capacity predictions formulated by in the EU white paper on renewable sources of energy. Other sources of power: technologies such as geothermal, tidal and wave power are still at the R&D stage, so they have not yet been included in the Renewable Energy Snapshots. Yet, they are likely to be introduced to the market within the next decade. As far as hydro generation is concerned, no major increase is expected, as most of the resources are already in use. However, pumped hydro will play an increasingly important role as in a storage capacity for the other renewable energy resources. Background The JRC has produced the annual Renewable Energy Snapshots since 2007 to give an up-to-date picture of the EU's progress towards the binding target of 20% for energy generation from renewable sources by 2020. These Renewable Energy Snapshots are based on two types of data: official figures from EU countries or EUROSTAT and those provided by industry associations, research industries, etc. This second type is known as "grey" data. It consists of more recent, unconsolidated data, which are needed for such an early analysis. They are cross-checked, consulted and validated by the JRC. However, due to the methodology of collection, va Text Box: European Commission Joint Research Centre Renewables account for 62 percent of the new electricity generation The "Renewable Energy Snapshots" report, published by the European Commission's Joint Research Centre, shows that renewable energy sources accounted for 62 percent of the new electricity generation capacity installed in the EU27 in 2009. The share rose from 57 percent in 2008. In absolute terms, renewables produced 19.9 percent of Europe's electricity consumption last year. Cautious optimism In 2009, and in absolute terms, about 19.9% (608 TWh) of Europe's total electricity consumption (3042 TWh) came from renewable energy sources. Hydro power contributed with the largest share (11.6%), followed by wind (4.2%), biomass (3.5%), and solar (0.4%). With regards to the new capacity constructed that same year (27.5 GW), among the renewable sources, 37.1% was wind power, 21% photovoltaics (PV), 2.1% biomass, 1.4% hydro and 0.4% concentrated solar power, whereas the rest were gas fired power stations (24%), coal fired power stations (8.7%), oil (2.1%), waste incineration (1.6%) and nuclear (1.6%) (see figure1). As not all installed technologies operate continuously 24 hours a day, figure 2 shows the expected yearly energy output (TWh) from the new capacity. The new gas-fired electricity plants will deliver yearly 28 TWh, followed by wind and PV with 20 TWh and 5.6 TWh, respectively. If current growth rates are maintained, in 2020 up to 1400 TWh of electricity could be generated from renewable sources, the report concludes. This would account for approximately 35-40% of overall electricity consumption in the EU, depending on the success of community policies on electricity efficiency, and would contribute significantly to the fulfillment of the 20% target for energy generation from renewables. However, it also advises that some issues need to be resolved if the targets are to be met. Particular areas of focus include ensuring fair access to grids, substantial public R&D support, and the adaptation of current electricity systems to accommodate renewable electricity. The study highlights that cost reduction and accelerated implementation will
Developed by American company Envision Solar, the Tracking Solar Tree features a hybrid multi-axis tracking design that enables the entire canopy to track the sun over the course of the day. This increases the renewable energy production by about 25 percent as compared to traditional solar panels. Over the course of a year, the Solar Tree will produce up to 30,000 kilowatt hours – enough solar energy to charge six electric vehicles per day. Speaking to PhysOrg, Rob Threlkeld, GM global manager of renewable energy said: “We are constantly looking for places where we can add a renewable focus. This solar tree is an ideal addition because not only does it provide a space to charge our electric vehicles, but it’s another step in our journey toward cleaner energy use.” Not only have Envision Solar created the Solar Tree, but they have also invented Solar Groove - a 186-vehicle parking lot that was converted into a 235 kW solar electric generating system for Kyocera. Desmond Wheatley, President and CEO of Envision Solar stated: ” Our Solar Tree structures can be installed in any location while our unique tracking solution allows us to always get the most from the sun. As such they are the perfect visible embodiment of GM and its dealerships commitment to the environment and the future of electric and other highly efficient vehicles. We look forward to installing many more of our iconic tracking Solar Tree structures for GM in the coming months.”