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View Full Version : Testing is the key to solar energy in Qatar


Pangea
12-08-2009, 12:58 PM
At the Copenhagen climate summit currently underway, there will be calls for it to get there much sooner.



Since solarís share of global power is only 0.1% today that would mean a very rapid pace of adoption. But after installing sustainable energy in hundreds of locations over almost a decade, our experience at Chevron is that rushing a solar project is a recipe for disappointment.



That is because solar energy is both elegantly simple and fiendishly complicated. On the surface it looks as easy as buying some solar panels, putting them in the sun, and enjoying endless free electricity. In the US you can buy a 400 watt panel online from Amazon.com and be powering your campsite by next weekend.



But for solar applications larger than that, it takes highly-trained experts to design the system, and there are hundreds of different technologies and products to choose between. Plus, a panelís efficiency is influenced by the local climate. When even modest solar power plants cost tens of millions of dollars, planners need to be absolutely certain how a panel will perform in real-world conditions.



This is especially important here in Qatar. Most solar cells are designed and installed in countries with mild climates like Germany, Japan and the US. But in the Middle East there is scant rain to wash dust off solar panels and, counter-intuitively, most solar cells actually perform worse as they get hotter.



And these effects are not small. In tests done in Saudi Arabia some years ago, photovoltaic solar cells left outside for six months lost a massive 40% of their efficiency due to accumulated dust. Other researchers found that even a fine layer of dust can be enough to cause efficiency to drop 10%.



The usual solution is to wash photovoltaic panels, but of course in Qatar water is scarce. Solar thermal power plants also need water, but as a coolant, and in fact in the western US the main obstacle to these plants right now is securing enough water.



Meanwhile, every 25C rise in the temperature of a photovoltaic cell causes its efficiency to fall by around a tenth. This is because as cells get hotter their electrons gain more energy and move about the cell in undesirable ways.



Here is the problem: A solar cellís performance is usually quoted under lab conditions where it is kept at 25C. Not only does it get much hotter than that in Qatar, but because it is in direct sunlight a cellís temperature can easily reach 30C higher than the surrounding air. Suddenly you have a cell which is not at 25C but perhaps at 70C or higher.



In other words, it is not enough to rely on a manufacturerís claim of efficiency, or even on real-world trials conducted in other countries. The only way to be certain of a solar panelís performance in Qatar is to test it in Qatar.



That is what Chevron and Qatar Science & Technology Park (QSTP) are doing. We are establishing a research and training facility that will investigate solar power, solar air-conditioning and low-energy lighting technologies. It is part of Chevronís $20mn Centre for Sustainable Energy Efficiency at QSTP, scheduled to open in October 2010.



Through this work we aim to provide local organisations with reliable data that will help them conduct solar feasibility studies, compare different technologies, and select the right products.



We will also bring the expertise of Chevron Energy Solutions (CES) to local organisations and projects. CES is now the largest installer of solar energy for education institutions in the US, and since 2000 its projects have saved more than $1bn of energy.



As those in Copenhagen point out, solar energy can make a valuable contribution to cutting carbon emissions. But all solar panels are not the same; it is vital to choose the right type and be confident of what it will deliver under real-world conditions. Through the partnership between Chevron and QSTP, Qatar is achieving that confidence.



Ben Figgis is external affairs and technology consultant at Chevron Qatar Ltd.



More... (http://www.worldofsolarthermal.com/index.php?do=viewarticle&artid=279)