Alternative+Energy



There are two forms of harnessing the sun's energy for use in our grid. The first method is by using concentrated solar power. This technology uses mirrors to reflect the sun's rays into a focal point. This concentrated energy and heat is used to raise the temperature of a substance like oil or salt. In Kramer Junction, CA, the oil is superheated, and it runs through a boiler, producing superheated steam that consecutively runs a turbine to generate electricity. This model is represented by the diagram below.

There are two other forms of concentrated solar power. Another form is the use of a solar dish. Thsi is a curved circular plate that uses a tracking system so that a large area of sunlight can focus onto a small area. The heat that is collected at the focal point heats a fluid in a chamber. A chamber adjacent to this is cool fluid. The expansion and contraction of fluids moves a piston that consecutively does work to run a turbine and generate electricity. Another form of collecting the sun's energy is busing a solar power tower. An array of mirrors is arranged in a circle, and they all focus to one spot at the center, the tower.

Photovoltaic cells on the other hand directly convert the sun's energy into electricity. A photovoltaic cell is composed of a positive plate and a negative plate. Photons of light excite electrons in one of the plates, and it travels to the opposite plate. This flow of electrons is electricity. Both of these technologies still face challenges in the market and in their technology.

The Solar Energy Generating Systems (SEGS) located in Southern California illustrates the potential and challenges in concentrated solar power. The Arizona Solar Project is a photovoltaic project that will be the largest PV generating facility in the world.

The first photovoltaic cell was invented by three individuals in 1954: Daryl Chapin, Calvin Fuller, and Geral Pearson. These cells performed at 4% efficiency, but it was later improved by them to be 11% efficient. Since then, photovoltaic cells have been implemented in several technologies, from a radio to one's calculator. In 1964, NASA launched a satellite powered by a photovoltaic array that produced 470 Watts. In 1977, the U.S. Department of Energy launched the Solar Energy Institute at the National Renewable Energy Lab. In that same year, photovoltaic manufacturing production exceeded 500 kW. In 1982, the world production exceeded 9.3 MW. That same year, the U.S. Department of Energy began operating Solar One, a 10 MW central receiver demonstration project tower system, implementing concentrating solar power. Finally in 1999, the efficiency of photovoltaic cells increased to 1000 MW.
 * Background**

Solar energy is already out in the U.S. market. According to the Energy Information Agency, the United States in 2009 produced 258.90 GW in renewable energy. Only 0.5178 GW was from solar energy, which is 0.2% of the renewable energy portfolio in the U.S. The energy from renewables in the U.S. is only 8%. The United States is lagging behind in the solar energy department. In 2010 Germany had 7.74 GW of photovoltaic energy, whereas the United States produced 0.95 GW of photovoltaic electricity. The solar energy market has been expanding rapidly in the world, and it is expanding in the United States as well. The leader in renewable energy and in solar energy is the state of California. California is underway several projects, 9 total recently, in solar energy. Some environmental concerns have risen regarding this technology, and several organizations are involved in the development of solar energy in the United States.

The U.S. Department of Energy is one of the biggest key actors in the development of CSP and PVs. The Energy Efficiency & Renewable Energy department exists under the DoE where several more programs exist. There is the Solar Energy Technologies Program, The SunShot Initiative, the Utility Solar Water Heating Initiative, and the US Department of Energy Solar Decathlon. The U.S. Department of Energy has further played a role in creating national laboratories that research and develop CSP and PV. These laboratories include the National Renewable Energy Laboratory (NREL), Sandia National Laboratories, Brookhaven National Laboratory, and Oak Ridge National Laboratory. Independent companies also play key roles in the PV and CSP industry. They are responsible for bringing these technologies to the market with the help of scales of economy. The top ten companies in photovoltaics include First Solar, Sungen Solar, Sharp, Q-Cells, Yingli, JA Solar, Kyocera, Trinia Solar, SunPower, and Gintech. Environmental Organizations have also been involved. These include the Defender of Wildlife, the Sierra Club, the Natural Resources Defense Council, and the Alliance for Responsible Energy Policy. The "California Desert Protection Act" was instilled in 2009 by Democratic Senator Dian Feinstein of California. The U.S. Bureau of Land Management has been responsible for issuing environmental impact statements to the solar project applications that are being submitted.


 * Project Analysis: Solar Energy Generating System (SEGS)**

SEGS is an amazing advancement in collecting the sun’s energy on the market. It took a lot of time before this idea could make it to the market, and it was made possible through the several funding from investors and government tax credits. This technology is limited to areas where weather conditions are favorable. The Mojave Desert has features of the desired weather attributes, but the Mojave Desert is also a habitat for the animals like the Mojave Desert squirrel, the burrowing owl, the Mojave Desert tortoise, and the flat-tailed horned lizard. Environmental advocates are against having concentrated solar power in the Mojave Desert. They want to protect this public land and the wildlife it contains. SEGS is located in the Mojave Desert in California. All SEGS use parabolic troughs, focusing the sun’s rays at 30 to 100 times its normal intensity to raise the oil’s temperature up to 750°F. SEGS I and SEGS II are both in Daggett, CA. SEGS I produced 14 MW of energy, but SEGS II produces 30 MW of electricity. SEGS III-VII are located in Kramer Junction, CA. These produce 30 MW each. SEGS VIII and SEGS IX are located in Harper Lake, CA, and they both produce 80 MW of energy each. Together, SEGS provides the most energy at peak hours, when it is needed the most. There has been ongoing research in parabolic trough systems and other means of concentrated solar power. For example, NREL has a sector dedicated to concentrating solar power research. They have focused on parabolic trough systems. NREL is working to increase the simplicity in the manufacturing of parabolic troughs, thereby improving the cost effectiveness. NREL has particularly focused on improving the materials used for the systems. The advancement of optical materials has been a spotlight in their Advanced Optical Materials Laboratory, for this facet is approximately 50% of the capital cost of the plants. They look to develop long-lasting and low-cost materials that will reflect, absorb, and transmit the sun’s energy efficiently. The disciplines in the NREL research staff consist of Mechanical Engineers, Chemical Engineers, Physicists, Chemists, and Material Scientists.

This project is located in the Mojave Desert of California because this area is characteristic of cloudless skies and dry air. The Mojave Desert has high altitude, so the sunlight has less distance and matter to travel through to reach the mirrors. All of these favorable conditions allow these hot regions of California to receive approximately 8.3 kWh/m2. According to NREL’s map of Concentrating Solar Resource map, this is the maximum that can be achieved. The Mojave Desert land is also low-cost.

Luz International Inc. was the driving force to commence and expand their solar technology, SEGS. A lot of funding was needed, and this was made possible through the several energy tax breaks from California state and the federal government in the 1980s. Several investors were also sought out to initially cover the construction costs of SEGS. While funding was one of the main barriers to advancing this project, another barrier was the rule set down by PURPA, which opened up markets to independent producers of energy, provided that they were no more than 30 MW in size. However, the support of solar energy has been growing, particularly due to the fears of the environmental hazards that fossil fuel energy brings and the Arab oil embargo.

$62 million was needed to build SEGS I. Starting was difficult because many investors were hesitant of the technology and in its ability in providing a profit in the early 1980s. The Federal government provided tax credits and a 25% investment in 1983 toward this project. A year later, SEGS I opened, providing 13.8 MW. In general though, the price of producing energy dropped from 24 cents to 12 cents for every kilowatt hour of electricity with more SEGS built over time. The combined energy was sold to Souther California (SoCal) Edison, providing the energy to 270,000 residential customers. Luz International Inc. had been able to make profits thanks to several tax incentives and other encouraging government regulations. These incentives however, were to cease in December 1989. The California tax credits and the Federal investment tax credit ended in 1988. The Federal energy tax credit was to end the same year, but it was extended. Other barriers to the advancement of this project included the relatively low priced oil and natural gas prices at the time. Additionally, the demand for solar energy was not as high as it is now. Luz International went out of business in 1991 because of low energy prices and because of the uncooperative policy changes. SEGS were handed over to the Kramer Junction Company.

Agua Caliente will be the largest working photovoltaic power plant in the world. The plant is expected to be completed by 2014. The Agua Caliente Solar project has a 25 year power purchase agreement with Pacific Gas and Electric Company, delivering clean energy to 225,000 homes. As with the concentrated solar technology, the photovoltaic plant poses an environmental obstruction in that it disrupts the habitat of rare desert animals.
 * Project Analysis: Arizona Solar Project**

Using advanced thin films as the main technology in the solar panels, it will generate 290 MW. The plant will not produce any emissions. This plant will have the capacity to offset 5.5 million metric tons of carbon dioxide in the span of 25 years. This is the same as removing 40,000 cars off the road every year. No waste material will be produced in the process, and no water will be consumed in the process. The plant will occupy 2400 acres of land between Yuma and Phoenix, AZ. Thin film photovoltaic cells are implemented in the Arizona Agua Caliente solar project. The main research in PVs is the type of material to use. First Solar uses Cadmium Telluride (CdTe) as the semiconductor in their photovoltaic arrays. A lot of research has gone into this particular material and many other substances. The particular concern with CdTe is that it may not be properly used in manufacturing and in residential applications. Health and environmental risks are associated with these elements. It must be carefully handled in order to obtain the maximum benefits from this material. In its stable form though, it will not leak into the atmosphere, even with temperatures as high as 1100°C. CdTe is used for its maximum absorbance of visible light. Cells made with this material can have 19% efficiency. NREL, Brookhaven National Lab, Columbia University, and George Washington University have done extensive research on this material. The type of disciplines needed in photovoltaic research are Material Science Engineers, Chemical Engineers, Systems Engineers, and Physicists. Several other disciplines are viable as well.

Through photovoltaic cells, Arizona can receive 6.8 kWh/m2 of the sun’s energy. According to NREL’s map of Photovoltaic Solar Resource map, this is the maximum that can be achieved. The Agua Caliente solar project is located in a desert, and like CSP, it poses a disturbance to local habitat. First Solar says that these solar panels do not require any use of water, so it will not be using any of Yuma County’s scarce water resources.

In December 2010, the project was submitted to qualify for a U.S. Department of Energy federal loan guarantee. This proved to be successfully, for the 290 MW Agua Caliente Solar project recently acquired $967 million in a loan guarantee from the U.S. Department of Energy through the Loan Program Office in January 2011. An additional $800 million is expected to be invested from NRG. The plant will create construction jobs for 400 individuals. The county tax will expand as well. Energy will be provided to 100,000 homes through Pacific Gas & Electric Company. The PV plant will avert the discharge of 237,000 metric tons of greenhouse gases every year. The Agua Caliente project will commence distributing electricity in 2012, and it will be able to produce the maximum energy in 2014.

The two types of solar power have their own distinct attributes and challenges. Both technologies are best situated in hot regions like the southern United States. According to NREL though, photovoltaics are more versatile in their implementation in the United States; they can perform well in more northern parts of the United States. The challenge in photovoltaic technology is heavily based on the type of material used. Different materials absorb different quantities and different types of electromagnetic radiation, and the mixing of these materials in the proper proportions will optimize the efficiency of light absorbance and transmission. The manufacturing of these materials is a concern, for heavy metals like cadmium and tellurium possess health risks. These must be handled safely. Photovoltaic cells can also be implemented on one's rooftop. This application requires maintenance from time to time. On average photovoltaic cells last up to 40 years. The challenge with concentrating solar power is also a matter of optical property material optimization. The process that CSP uses is different than that of PV, for it converts the sun's energy through a secondary means. Different efficiencies are associated with the distinct ways in which CSP is established. Both technologies, when implemented in public desert regions, are a threat to animals' habitats. The Mojave Desert squirrel is endangered, and several environmentalist groups want the government to administer solar technology responsibly. Solar companies have been decreasing their initially proposed capacity to protect the environment, and they are also making innovative changes to their designs to decrease the use of the scarce water in their systems. Solar companies must maintain the environment as a priority as usual, so it is great that they go back to the drawing board to redesign their projects. While renewable energy is important to incorporate into the United States, it is also still important that it is established safely and logically. More research and improvements can be made to these systems. For now, they are still a great source of clean energy. Millions of people are benefiting from these technologies. Emissions are decreased, providing better air quality for residents. The U.S. Department of energy must continue to fund solar energy projects and other renewable energy projects, making sure that an interdisciplinary independent team evaluate the benefits and potential hazards that these systems may possess.
 * Conclusion**

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 * References**

<span style="font-family: Tahoma,Geneva,sans-serif; font-size: 10pt;"> Context: <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="background: white; line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; mso-add-space: auto; text-indent: -.5in;"><span style="color: black; font-family: Tahoma,sans-serif; font-size: 10pt;">"CdTe (CADMIUM TELLURIDE)." //First Solar FSLR - Thin Film Solar Modules//. Web. <http://www.firstsolar.com/en/CdTe.php>. <span style="background: white; line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; mso-add-space: auto; text-indent: -.5in;"><span style="color: black; font-family: Tahoma,sans-serif; font-size: 10pt;">"EIA's Energy in Brief: How Much Renewable Energy Do We Use?" //How Much of Our Electricity Is Generated from Renewable Sources?// Web. <http://eia.gov/energy_in_brief/renewable_energy.cfm>. <span style="background: white; line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; mso-add-space: auto; text-indent: -.5in;"><span style="color: black; font-family: Tahoma,sans-serif; font-size: 10pt;">"Global PV Market." //Solar Buzz Solar Market Research and Analysis//. Web. <http://www.solarbuzz.com/facts-and-figures/market-facts/global-pv-market>. <span style="background: white; line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; mso-add-space: auto; text-indent: -.5in;"><span style="color: black; font-family: Tahoma,sans-serif; font-size: 10pt;">Koshmrl, Mike. "DOE Back World's Largest PV Plant." //Solar Today//. 21 Jan. 2011. Web. <http://www.ases.org/index.php?option=com_myblog&show=DOE-backs-worlds-largest-PV-plant-.html&Itemid=27>. <span style="background: white; line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; mso-add-space: auto; text-indent: -.5in;"><span style="color: black; font-family: Tahoma,sans-serif; font-size: 10pt;">Maloney, Peter. "Solar Projects Draw New Opposition." //The New York Times// 24 Sept. 2008. Web. <http://www.nytimes.com/2008/09/24/business/businessspecial2/24shrike.html?scp=3&sq=kramer%20junction&st=cse>. <span style="background: white; line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; mso-add-space: auto; text-indent: -.5in;"><span style="color: black; font-family: Tahoma,sans-serif; font-size: 10pt;">Moore, Meredith, and Alan Bernheimer. "NRG to Acquire 290-Megawatt Agua Caliente Solar Project from First Solar." //First Solar-News Release//. First Solar, 14 Dec. 2010. Web. <http://investor.firstsolar.com/phoenix.zhtml?c=201491&p=irol-newsArticle&ID=1507800&highlight=>. <span style="background: white; line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; mso-add-space: auto; text-indent: -.5in;"><span style="color: black; font-family: Tahoma,sans-serif; font-size: 10pt;">"NREL: CdTe - Perspective." //National Renewable Energy Laboratory (NREL) Home Page//. Web. <http://www.nrel.gov/pv/cdte/perspective.html>. <span style="background: white; line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; mso-add-space: auto; text-indent: -.5in;"><span style="color: black; font-family: Tahoma,sans-serif; font-size: 10pt;">Streater, Scott. "California Desert on Pace to Become World's Solar Capital." //The New York Times// 13 Aug. 2010. Web. <http://www.nytimes.com/gwire/2010/08/12/12greenwire-calif-desert-on-pace-to-become-worlds-solar-ca-32699.html>. <span style="background: white; line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; mso-add-space: auto; text-indent: -.5in;"><span style="color: black; font-family: Tahoma,sans-serif; font-size: 10pt;">U.S. Department of Energy. "The History of Solar." Web. <http://www1.eere.energy.gov/solar/pdfs/solar_timeline.pdf>. <span style="background: white; line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; mso-add-space: auto; text-indent: -.5in;"><span style="color: black; font-family: Tahoma,sans-serif; font-size: 10pt;">Weiss, Michael J. "Everybody Loves Solar Energy, But..." //The New York Times// 24 Sept. 1989. Web. 5 May 2011. <http://www.nytimes.com/1989/09/24/magazine/everybody-loves-solar-energy-but.html?scp=1&sq=kramer%20junction&st=cse>. <span style="font-family: "Tahoma","sans-serif"; font-size: 10.0pt;">

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