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	<title> &#187; PV</title>
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		<title>Economic Review of the International PV Industry</title>
		<link>http://www.greencon.co.za/blog/2009/09/economic-review-of-the-international-pv-industry/</link>
		<comments>http://www.greencon.co.za/blog/2009/09/economic-review-of-the-international-pv-industry/#comments</comments>
		<pubDate>Thu, 03 Sep 2009 08:50:05 +0000</pubDate>
		<dc:creator>admin</dc:creator>
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		<guid isPermaLink="false">http://www.greencon.co.za/blog/?p=726</guid>
		<description><![CDATA[South African PV industry is still in it&#8217;s embrionic phase, but there are some nice signs from NERSA and the like. We thought it would be useful to post some industry research abouth the status of the international PV industry. Make for some intersting reading&#8230; As an industry, the photovoltaic sector has witnessed its share [...]]]></description>
			<content:encoded><![CDATA[<div class="newsSubHeader">South African PV industry is still in it&#8217;s embrionic phase, but there are some nice signs from NERSA and the like. We thought it would be useful to post some industry research abouth the status of the international PV industry. Make for some intersting reading&#8230;</div>
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<div class="newsSubHeader">As an industry, the photovoltaic sector has witnessed its share of ups and downs but it has nonetheless recorded 30 years of growth. How is the sector dealing with falling revenues in 2009?</div>
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<div class="viewStoryAuthor">After four years of boom times in the solar industry, a significant softening of demand along with lower module prices has led to anxious times &#8212; fewer sales, at lower selling prices and so lower revenues and, significantly, lower profits.</div>
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<p>Even without the expected decrease in demand in 2009, technology revenues would be lower than the US $20.4 billion (€14 billion) of 2008 as cell and module prices are around 40% below 2008 levels. Figure 1 <em>(shown below)</em> provides technology revenues from the manufacturer to the first point of sale in the market from 2003 through 2013. For 2009 and 2010, an estimate of revenues for the recession forecast has been provided. With technology prices at the current level, even growth in sales volume, which is highly unlikely, would result in lower revenues in 2009.</p>
<p><img src="http://www.renewableenergyworld.com/assets/images/story/2009/8/31/2-1332-the-pv-industry-2009-in-search-of-stability-and-sustainability.jpg" alt="" /></p>
<p>Figure 1. Worldwide module revenue volume for recession, conservative and accelerated growth models 2003-2013.</p>
<p>Accelerated growth in the photovoltaic industry continued in 2008, with 79% market growth over the previous year to 5.5 GW. Unfortunately, the market was significantly oversold in 2008, stranding around 2 GW of product in supply side inventory at the beginning of 2009.</p>
<p>Most of the overselling was into Spain, which with a market volume coming in at 2.3 GW in 2008, represented 42% of total photovoltaic system sales worldwide. Along with high prices for modules and PV systems, quite a few instances of poor module product and poorly constructed systems, and permit speculation, the oversold market led the Spanish government to alter its support programme. The new decree capped the market, lowered the feed-in tariff and effectively closed Spain to new product sales for perhaps two years, or more.</p>
<p>Other than Germany, the <a href="http://www.greencon.co.za/products-display-2-solar_electricity__photvoltaic_panels.htm">PV</a> industry currently has no other global market capable of accepting a volume of sales remotely similar to Spain. Moreover, the global recession and financial crises have further hobbled an industry that had been enjoying accelerated growth since 2004. For these reasons, the PV industry is set to experience its first decrease in demand in more than 30 years — and not just flat growth, but a decrease in sales volume of perhaps 30%, or even more.</p>
<p>Figure 2, <em>(below)</em>, provides data for 35 years of PV industry growth, from 1974 through 2008, while Figure 3, <em>(below)</em>, reveals three forecast scenarios for 2009, which are on based on assumptions related to recession, conservative and accelerated growth for the sector.</p>
<p>Though the PV industry enjoyed accelerated growth from 2004 through 2008, this rate will not continue in 2009, and accelerated growth is unlikely into 2010. In 2009, lending from the international debt markets continues to be depressed. Meanwhile, the loss of a major market — Spain — is having a deleterious effect on growth, inventories remain high, and global economies remain in recession.</p>
<p><img src="http://www.renewableenergyworld.com/assets/images/story/2009/8/31/3-1332-the-pv-industry-2009-in-search-of-stability-and-sustainability.jpg" alt="" /></p>
<p>Figure 2. Photovoltaic industry history 1974-2008 (CAGR = compound annual growth rate).</p>
<p>Furthermore, although market development is underway, Germany remains the only market capable of consuming more than a gigawatt of product, and other markets, such as Italy, are underperforming. Japan, South Korea, the United States and others continue to experience slow growth. The good news is that module prices in the soft market seen in 2009 continue to decrease significantly.</p>
<p>As previously noted, while the PV industry has experienced slow or flat growth so far this year — to July 2009 — it is an industry that has not experienced negative growth in 35 years or more. Conversely, years of significant strong growth of more than 70% include: 1975 at 150%, 1976 at 141%,1977 at 87%, 1978 at 112%, 1980 at 128%, 1983 at 88%, and 2008 at 79%.</p>
<p>Since 1974, the PV industry has only experienced three years of soft growth, defined here as demand growth of less than 10% in a given year: 1986 at 8%, 1993 at 3% and, 1994 at 10%.</p>
<p class="subhead"><strong>The Incentive Driver</strong></p>
<p>Historically, the PV industry has enjoyed strong growth, though at much lower volumes than today. The strong growth that the PV industry enjoyed since 2004 was driven by incentives, in particular, the feed-in tariff laws in Europe, and even more specifically, Spain’s generous programme. Though for countries in Europe (in general) there is no reason to assume that <a href="http://www.greencon.co.za/products-display-2-solar_electricity__photvoltaic_panels.htm">feed-in tariff</a> programmes will stop altogether, the problems experienced in Spain (overselling, fraud and poor quality products among them) are having a sobering effect on government incentive planning in other EU countries. The support programmes of the future will need to include mechanisms that manage growth along with stimulating it.</p>
<p>The incentives that the industry relies on come with downward price pressure, which is a significant constraint. However, given the goal of grid parity, there is literally nowhere for price to go but down. Grid parity, nonetheless, is a complex subject, differing in most global markets. Moreover, grid parity provides a level competitive playing field for solar (a worthwhile goal on its own), but does not ensure success.</p>
<p>The industry also needs an increasing number of highly trained installers, sales personnel, engineers and such like, and this comes at a cost. Lower costs and prices are necessary for the continuation of incentives and, therefore, demand. For accelerated growth to continue, and for the eventual slowing of demand to happen gradually, unlike the expected steep decline in 2009, the PV industry must learn to manage its demand. It must develop incentives with triggers to control demand when it accelerates too quickly.</p>
<p>The industry must also control its supply chain from expensive raw material, to consumables, and through to the end user, and must participate with balance of systems (BOS) manufacturers to innovate and develop inexpensive and robust BOS. All raw materials, consumables and machinery are more expensive at this point because of the higher price of oil, which is necessary for transportation.</p>
<p>Other caveats to limitless growth are the high price of <a href="http://www.greencon.co.za/products-display-2-solar_electricity__photvoltaic_panels.htm">PV systems</a>, and the availability of less expensive alternatives, including conventional energy sources such as natural gas and coal. In recent years, the current high volume of industry demand, coupled with raw material shortages, threw the industry into a panic. Instead of the technology standard, ‘if we build it they will come,’ the new mantra became, ‘they are coming and we can’t build it.’</p>
<p>The industry reacted by buying silicon feedstock and cell futures, and by raising component (module) and system average prices, globally. These long-term contracts for raw material, wafers and cells are proving unsupportable and in many cases, are being rewritten or ignored.</p>
<p><img src="http://www.renewableenergyworld.com/assets/images/story/2009/8/31/4-1332-the-pv-industry-2009-in-search-of-stability-and-sustainability.jpg" alt="" /></p>
<p class="subhead">Figure 3. Recession, conservative and accelerated forecast scenarios for grid-connected PV, 2008-2013.</p>
<p class="subhead"><strong>The Past Can Inform the Future</strong></p>
<p>It is useful to study specific periods in the PV industry’s history, in terms of growth and drivers for growth, to see what can be learned from these periods which can be useful in understanding the direction of this still young industry. Figure 2, offers compound annual growth rates for the PV industry for specific periods, 1974–1984, 1984–1994, 1994–2004 and 2004–2008.</p>
<p>During 1974–1984, strong compound annual growth of 84% was due to utility and government-backed grid-connected demonstration projects. During this period, the grid-connected application was 30%–50% of total demand, though from annual totals less than 20 MW. Following this decade-long period of significant growth, lower compound annual growth of 13% for 1984–1994 was due to an almost complete cessation of these projects. During this period, grid-connected applications (primarily unsubsidized or incentivized) was less than 10% of annual demand.</p>
<p>Stronger compound annual growth of 33% during 1994–2004 reflects the beginning and continuation of the strong incentive programmes that continue to drive PV industry growth. Specifically in Europe, the feed-in tariff model has proven to be the most successful incentive model. Japan’s residential rooftop programme in the late 1990s, a capacity subsidy, built a sustainable market for solar roofs in that country. In the US, incentives in California created the most significant market in that country.</p>
<p>The 2004–2008 period also managed to encompass two significant events for the sector: the PV industry’s greatest raw material (silicon feedstock) shortage and its strongest period of sustained accelerated growth.</p>
<p><img src="http://www.renewableenergyworld.com/assets/images/story/2009/8/31/6-1332-the-pv-industry-2009-in-search-of-stability-and-sustainability.jpg" alt="" width="300" height="300" />During this period, demand for large field grid-connected applications in Europe, largely driven by the feed-in tariff model of incentives, created the largest global market (79% in 2008) for solar systems. However, the solar-grade silicon raw material shortage that had pushed up prices for crystalline silicon modules also created an entry point for thin-film technologies, which had previously been viewed as risky. The industry’s compound annual growth for this period was 51%.</p>
<p class="subhead"><strong>Grid-connected Growth Drivers</strong></p>
<p>Like it or not &#8230; strong growth in the PV industry comes with strong growth in grid-connected applications. Off-grid (remote) applications show slow, steady growth over time, but have not driven the industry into gigawatt sales. It is the grid-connected applications (residential, small, medium and large commercial, large field commercial and utility) that dominate the market for photovoltaic modules. Indeed, at 94% of total sales in 2008, the volume of grid-connected installation leaves very little module product available for off-grid applications.</p>
<p>The grid-connected application remains driven by government subsidy/support programmes (Europe’s feed-in tariffs, US rebates, for example). Without such programmes the market for grid-connected PV products would decrease dramatically. The significant decrease in demand in 2009 is a lesson to the industry about the significant changes that could take place in demand, revenues and profitability when markets are abused, and when so-called ‘black swan’ events, such as the global recession, alter the playing field and force reactive market and price setting.</p>
<p>Figure 3 <em>(shown above)</em> offers an aggregate five-year forecast for grid-connected applications. The recession forecast is presented in Figure 3, but is considered a two-year anomaly. Meanwhile, Figure 2 excludes <a href="http://www.greencon.co.za/products-display-2-solar_electricity__photvoltaic_panels.htm">off-grid applications</a>. However, at more than 90% of the total market demand, the volume of grid-connected applications effectively represents the total industry volume.</p>
<p>All is not doom and gloom, however, with encouraging current market developments in the US and some other countries. There is continued progress in lowering manufacturing costs so that a reasonable margin can be maintained along with lower system prices. We see progress in increasing efficiencies for all technologies, and business model innovations, meaning that accelerated growth will resume for the PV industry. Certainly, at this stage in PV industry development (which could be likened to its preadolescence) there is room to grow and much to learn before a stable, sustainable level of annual growth settles in. Until then, exciting, and sometimes painful times remain ahead.</p>
<p>Source: Renewable Energy World</p>
<p>Keep it <a href="http://www.greencon.co.za/products.htm">Green </a></p>
<p><a href="http://www.greencon.co.za/products.htm">Greencon</a></div>
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		<title>What is the carbon cost of PV</title>
		<link>http://www.greencon.co.za/blog/2008/11/what-is-the-carbon-cost-of-pv/</link>
		<comments>http://www.greencon.co.za/blog/2008/11/what-is-the-carbon-cost-of-pv/#comments</comments>
		<pubDate>Fri, 21 Nov 2008 10:22:51 +0000</pubDate>
		<dc:creator>admin</dc:creator>
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		<guid isPermaLink="false">http://www.greencon.co.za/blog/?p=77</guid>
		<description><![CDATA[It is our desire to always be open and transparent. We at Greencon have always been a little concerned about the actual carbon cost of PV . I have searched far and wide to get a conclusive answer. I stumbled upon this, give me your thoughts: The environmental cost is Negative in the production of [...]]]></description>
			<content:encoded><![CDATA[<p><a href="http://www.greencon.co.za/blog/wp-content/uploads/2008/11/121.jpg"><img class="alignleft size-thumbnail wp-image-186" title="121" src="http://www.greencon.co.za/blog/wp-content/uploads/2008/11/121-150x150.jpg" alt="" width="150" height="184" /></a>It is our desire to always be open and transparent. We at <a href="http://www.greencon.co.za">Greencon</a> have always been a little concerned about the actual carbon cost of <a href="http://www.greencon.co.za/products-display-2-pv_panels.htm">PV</a> . I have searched far and wide to get a conclusive answer. I stumbled upon this, give me your thoughts:</p>
<p>The environmental cost is Negative in the production of most PV panels. This is a very common misconception about solar panels. Everyone thinks that because they don&#8217;t create any waste by themselves that they are this ultimate clean energy source. None thinks about where the materials for the panel came from. The glass, metal, and all the little connectors used in assembling a solar panel don&#8217;t take much energy to build but the actual Photovoltaic material DOES!</p>
<p>The vast majority of PV panels are made from silicon that is created in High pressure, high temperature (1650 degrees C) machines. This method is very energy intensive and unfortunately the amount of energy it takes to produce that high quality silicon is more than the solar panels made from the silicon will ever be able to recover. Add on top of that all of the other processes to &#8220;dope&#8221; the silicon so it will transfer electrons and the cost just keep rising.</p>
<p>To really understand you would need to look into the production of semiconductors. I don&#8217;t have any exact numbers because semiconductor manufacturers don&#8217;t tell us how much energy they consume so you would have to get a hold of one of their bills to really find out. But my semiconductor professor in college gave us an estimate that was a magnitude larger than the life time capacity of your average solar panel.</p>
<p>Sadly, overall right now PV solar panels are not efficient enough to be used as an energy production method except in cases in of extreme remote locations like Space, at sea, or other places away from a power grid.</p>
<p>Of course Thermal Solar systems are totally different, using the sun&#8217;s heat creates steam to generate electricity or to transfer that heat for some other use is a great use of free energy. Production of mirrors or dark glass materials is cheap compared to PV panels.</p>
<p>When it comes to solar cells, there is good news and there is bad news. First the bad news. Installing photovoltaic solar panels on your roof will cost you more than you save on electricity bills before the panels have to be replaced. The good news is that you will reduce your carbon footprint and save energy. That is the conclusion drawn from a study published in Inderscience International Journal of Environmental Technology and Management.</p>
<p>Solar and <a href="http://www.greencon.co.za/products-display-8-wind_power_generation.htm">wind power</a>, and other <a href="http://www.greencon.co.za/products-display-1-solar_water_heating.htm">renewable sources</a>, such as wave and tidal power, represent an energy source that could underpin a sustainable energy policy by minimizing our reliance on fossil fuels and at the same time reducing carbon dioxide and other pollutant emissions. The main barrier that has so far hindered the development of a steady market for such &#8220;renewable&#8221; systems has been their cost.<a href="http://www.greencon.co.za/blog/wp-content/uploads/2008/11/131.jpg"><img class="alignright size-medium wp-image-187" title="131" src="http://www.greencon.co.za/blog/wp-content/uploads/2008/11/131-300x234.jpg" alt="" width="300" height="234" /></a></p>
<p>According to Giacomo Bizzarri of the University of Ferrara and Gianluca Morini of the University of Bologna, the amount of electricity that can be saved over the lifetime of a domestic PV panel is about 2000 kWh per square meter for thin film modules, with an expected life of 20 years, single-crystalline silicon devices with an anticipated lifespan of 25 years fare better producing 4400 kWh per square metre. However, the initial costs are about 2.5 times the value of the electricity produced, the researchers say.</p>
<p>The pair carried out a cost-benefit analysis and found that the total energy produced over a two-year period outweighs the energy used in manufacture, installation, and maintenance. Their analysis also shows that the manufacture and use of PV panels produces less pollution than fossil fuel based electricity generation.</p>
<p>The researchers say that their analysis holds even in countries with medium sunshine. This makes PV panels a viable alternative energy supply but will not save you money, unless the price of electricity rises three to four times, which will give a positive internal rate of return.</p>
<p>Bizzarri and Morini point out that cost should not be the only consideration. The total energy and pollution involved in sourcing the raw materials, manufacturing, installing, and maintaining any particular system should also be considered. After all, if it uses far more energy to build a wind farm or install solar panels than the energy they can produce during their lifetime then it does not make environmental or economic sense to install them.</p>
<p>With this in mind, the researchers analysed all the costs from cradle to grave &#8211; in terms of energy use, pollution and carbon footprint, and economic &#8211; to find out whether photovoltaic cells are a truly viable alternative energy source.</p>
<p>Three different kinds of PV devices were assessed: single-crystalline silicon, polycrystalline silicon, and thin film copper indium diselenide. The team considered the costs from the point of manufacture to end-of-life disposal. &#8220;Our study considers the systems through the whole of their life cycle, &#8220;from cradle to grave&#8221;, the researchers explain, &#8220;leading to the estimation of the energy, economic and emission payback times.&#8221;</p>
<p><a href="http://www.greencon.co.za/blog/wp-content/uploads/2008/11/141.jpg"><img class="alignleft size-thumbnail wp-image-188" title="141" src="http://www.greencon.co.za/blog/wp-content/uploads/2008/11/141-150x150.jpg" alt="" width="150" height="150" /></a>In their assessment of the three different PV panel types on the south-facing roof of a school in Ferrara, northern Italy, the team found that the energy produced by the panels over their lifetimes considerably overcomes the energy needed during manufacture. In fact, energy costs are recovered within two years in this medium sunshine climate. The team also showed that carbon dioxide emissions are significantly lower over the PV panel lifetime from cradle-to-grave compared with conventional electricity generation. Economic costs, the team found, would only be recouped if the panels remained fully functional for more than twenty years.</p>
<p>The researchers suggest that their study, which takes into account all the hidden costs in terms of energy, pollution, and money, could provide a role model for policy makers considering renewable energy sources.&#8221;</p>
<p>Well it does seem to pay it self back, and although there is a manufacturing cost to the environment it seems far reduced from coal fired energy costs.</p>
<p>Keep it <a href="http://www.greencon.co.za/products.htm">Green</a></p>
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		<title>Improving Exisiting Collector Properties</title>
		<link>http://www.greencon.co.za/blog/2008/11/improving-exisiting-collector-properties/</link>
		<comments>http://www.greencon.co.za/blog/2008/11/improving-exisiting-collector-properties/#comments</comments>
		<pubDate>Fri, 21 Nov 2008 09:35:04 +0000</pubDate>
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		<description><![CDATA[Some important questions about the possible future of PV technology by Elizabeth A. Thomson A Q&#38;A by the MIT research team led by Marc A. Baldo, the Esther and Harold E. Edgerton Career Development Associate Professor of Electrical Engineering, on solar concentrators. What did we do? We demonstrated a large improvement in the performance of [...]]]></description>
			<content:encoded><![CDATA[<p class="MsoNormal" style="margin: 0cm 0cm 5pt; line-height: 32pt; mso-outline-level: 2;"><span style="font-size: 28pt; color: black;"><span style="font-family: Times New Roman;"> </span></span></p>
<p class="authorinfo1" style="margin: 0cm 0cm auto;"><span style="font-family: Arial;"><span style="font-size: small;"><span style="color: #666666;">Some important questions about the possible future of <a href="http://www.greencon.co.za/products-display-2-pv_panels.htm">PV technology</a></span></span></span></p>
<p class="authorinfo1" style="margin: 0cm 0cm auto;">
<p class="authorinfo1" style="margin: 0cm 0cm auto;">by <span style="font-family: Arial;"><span style="font-size: small;"><span style="color: #666666;">Elizabeth A. Thomson</span></span></span></p>
<p class="authorinfo1" style="margin: 0cm 0cm auto;">
<p class="MsoNormal" style="margin: 0cm 0cm 0pt; vertical-align: top; line-height: 16pt; mso-margin-bottom-alt: auto;"><span style="font-size: small;"><em><span style="font-family: Arial; color: black;">A Q&amp;A by the MIT research team led by Marc A. Baldo, the Esther and Harold E. Edgerton Career Development Associate Professor of Electrical Engineering, on solar concentrators.</span></em></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt; vertical-align: top; line-height: 16pt; mso-margin-bottom-alt: auto;"><span style="font-size: small;"><strong><span style="font-family: Arial; color: black;">What did we do?</span></strong><span style="font-family: Arial; color: black;"> We demonstrated a large improvement in the performance of low-cost solar concentrators. Our new devices increase the power obtained from <a href="http://www.greencon.co.za/products-display-2-pv_panels.htm">solar cells</a> by a factor of over 40 without needing to track the sun. Our results are at least a factor of four better than previous results.<sup><a href="http://web.mit.edu/newsoffice/2008/solarcells-faq-0710.html#1#1"><span style="color: #993333;">1</span></a></sup></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt; vertical-align: top; line-height: 16pt; mso-margin-bottom-alt: auto;"><span style="font-size: small;"><strong><span style="font-family: Arial; color: black;">Why is this important?</span></strong><span style="font-family: Arial; color: black;"> The sun is an inexhaustible source of clean power. The major impediment to widely deployed solar-power systems has been cost. Unsubsidized solar electricity is over three times as expensive as the average grid prices for electricity derived from conventional energy sources, according to the U.S. Department of Energy. Dramatic cost reductions are needed. Clean, renewable electricity at affordable prices would be an attractive alternative to conventional electricity and the related fossil-fuel dependence, greenhouse-gas emissions and peak-time grid constraints. </span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt; vertical-align: top; line-height: 16pt; mso-margin-bottom-alt: auto;"><a href="http://www.greencon.co.za/blog/wp-content/uploads/2008/11/9.jpg"><img class="alignleft size-medium wp-image-181" title="9" src="http://www.greencon.co.za/blog/wp-content/uploads/2008/11/9-300x267.jpg" alt="" width="300" height="267" /></a><span style="font-size: small;"><strong><span style="font-family: Arial; color: black;">What is a solar cell?</span></strong><span style="font-family: Arial; color: black;"> Solar cells transform sunlight into electricity by using a semiconductor device, typically made of silicon. <a href="http://www.greencon.co.za/products.htm">Solar cells are packaged into solar panels</a></span></span><span style="font-size: small;"><span style="font-family: Arial; color: black;">, which can be installed on rooftops or large fields. The solar cells are typically some of the most expensive parts of an installed solar panel.</span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt; vertical-align: top; line-height: 16pt; mso-margin-bottom-alt: auto;"><span style="font-size: small;"><strong><span style="font-family: Arial; color: black;">What is a solar concentrator?</span></strong><span style="font-family: Arial; color: black;"> Solar concentrators collect light over large areas and focus it onto smaller areas of solar cells. This increases the electrical power obtained from each solar cell. Solar concentrators can reduce the cost of solar power since more electricity is obtained per solar cell, and fewer solar cells are needed. </span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt; vertical-align: top; line-height: 16pt; mso-margin-bottom-alt: auto;"><span style="font-size: small;"><strong><span style="font-family: Arial; color: black;">What is wrong with existing solar concentrators?</span></strong><span style="font-family: Arial; color: black;"> Conventional solar concentrators track the sun to generate high optical intensities, often by using large mobile mirrors that are expensive to deploy and maintain. Solar cells at the focal point of the mirrors must be cooled, and the entire assembly wastes space around the perimeter to avoid shadowing neighboring concentrators. </span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt; vertical-align: top; line-height: 16pt; mso-margin-bottom-alt: auto;"><span style="font-size: small;"><strong><span style="font-family: Arial; color: black;">What is our technology?</span></strong><span style="font-family: Arial; color: black;"> Our devices are based on a concept from the 1970&#8242;s that was largely abandoned: the luminescent solar concentrator (LSC). Our version of this device consists of a piece of transparent glass or plastic plate with a thin film of dye molecules deposited on the face and inorganic solar cells attached to the edges. Light is absorbed by the dye coating and reemitted into the glass or plastic for collection by the solar cells. </span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt; vertical-align: top; line-height: 16pt; mso-margin-bottom-alt: auto;"><span style="font-size: small;"><strong><span style="font-family: Arial; color: black;">Why did LSCs fail in the 1970&#8242;s?</span></strong><span style="font-family: Arial; color: black;"> Two reasons: the collected light was absorbed before it reached the edges of the glass or plastic plates, and the dyes were unstable. </span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt; vertical-align: top; line-height: 16pt; mso-margin-bottom-alt: auto;"><span style="font-size: small;"><strong><span style="font-family: Arial; color: black;">What precisely did you do to reduce loss of the collected light?</span></strong><span style="font-family: Arial; color: black;"> We borrowed some ideas from lasers, introducing what is known in lasers as a four-level system. In practice, we added a small concentration of an extra dye that collected all the absorbed light from its surrounding dye molecules. We also introduced a new class of dye molecules, known as molecular phosphors, that are extremely transparent to their own light emission.</span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt; vertical-align: top; line-height: 16pt; mso-margin-bottom-alt: auto;"><span style="font-size: small;"><strong><span style="font-family: Arial; color: black;">What about stability?</span></strong><span style="font-family: Arial; color: black;"> We tested one of our devices and found that it was stable (to 92 percent of initial performance) for three months. This isn&#8217;t good enough yet for products but we are confident that the technology developed for organic light emitting devices (OLEDs) in televisions will be portable to this application.</span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt; vertical-align: top; line-height: 16pt; mso-margin-bottom-alt: auto;"><span style="font-size: small;"><strong><span style="font-family: Arial; color: black;">When will these concentrators make it into production?</span></strong><span style="font-family: Arial; color: black;"> The technology is being further developed for commercialization by Covalent Solar, a company being spun out of MIT by three of its inventors: Michael Currie, Jon Mapel, and Shalom Goffri. The team believes that it could be implemented within three years.</span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt; vertical-align: top; line-height: 16pt; mso-margin-bottom-alt: auto;"><span style="font-size: small;"><strong><span style="font-family: Arial; color: black;">References</span></strong></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt; vertical-align: top; line-height: 16pt; mso-margin-bottom-alt: auto;"><a name="1"></a><span style="font-family: Arial; color: black;"><span style="font-size: small;">1. Currie, M. J., Mapel, J. K., Heidel, T. D., Goffri, S. &amp; Baldo, M. A. High-efficiency Organic Solar Concentrators for Photovoltaics. Science. In Press.</span></span></p>
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