Renewable energy is becoming more desirable than ever. Solar power plants are now used worldwide as a means to generate clean, “green” electricity. In an effort to increase these resources, the Arizona Public Service Company has partnered with Abengoa Solar to build one of the largest solar power plants in the world.
“APS is committed to making Arizona the solar capital of the world, bringing affordable renewable energy to all our customers,” said APS president Don Brandt. “The Arizona Corporation Commission has challenged Arizona utilities to be leaders in renewable energy, and we are responding aggressively.”
Aptly named after the Spanish word for “sunny place,” the Solana Generating Station will be a 280- megawatt concentrating solar power plant when completed. However, concentrating solar power works differently from the more widely known method of photovoltaic cells to trap the sun’s energy. Photovoltaic cells, better known as solar panels, use the sun’s light to create electricity. Concentrating solar power, by contrast, employs the sun’s heat. In CSP, parabolic trough reflectors are attached to computer-controlled motors to track the sun’s path throughout the day. The reflectors are made of mirrors that focus the sunlight onto receiving tubes located along the trough’s focal line. These contain a heat transfer fluid that reaches approximately 400 degrees Celsius when heated by the sun’s rays. The heated fluid converts water into steam, which then creates electricity by turning the power plant’s turbines.
A downside to solar panels: they can only produce electricity when directly hit by the sun’s rays. Through resourceful technology, Solana will be able to generate electricity even when the sun is not shining. Molten salt will be stored in large ‘thermoslike’ containers standing beside a series of steam generators. Periodically, the heat transfer fluid will heat the molten salt instead of creating steam that turns the turbines. Electricity could be generated for hours after the sun has set, by heating fluid using the molten salt in place of the trough reflectors.
Solana will be located in Gila Bend, Arizona, approximately 112 kilometres southwest of Phoenix. Arizona is perfectly suited for solar power concentration, as the Grand Canyon state receives plenty of heat from the sun all-year round. The generating station will have 2,700 parabolic trough reflectors, spanning approximately five square kilometres. Solana anticipates being fully operational in 2011. However, this is contingent on a number of factors, such as whether Congress renews the clean energy tax credit, scheduled to expire at the end of this year. When operating at full capacity, Solana will be able to generate electricity for 70,000 APS customers without any greenhouse gas emissions.
“This is a major milestone for Arizona in our efforts to increase the amount of renewable energy available in the United States,” said Arizona governor Janet Napolitano. “Arizona is leading the way in protecting our world for future generations through combatting climate change, fighting for air quality and much more. This plant will offer Arizonans a clean and efficient source of energy.”
