Currently, fossil fuels such as oil, coal and natural gas are being extensively used to produce electricity. These traditional sources of energy pose several challenges including security and environmental concerns and rising prices.
Government and businesses in countries around the world are, therefore, increasingly supporting the efforts to develop alternative sources of energy. Solar power generation is growing rapidly because of the several advantages it offers over other renewable sources.
What Is Neveda Solar One? – A Snapshot
The utility-scale power plant commissioned in 2007 is spread over 400 acres of land and generates 64 MW of nominal power without any carbon emissions. In fact, the carbon dioxide emissions avoided is equivalent to emissions from 20,000 cars annually. The power plant serves as many as 14,000 homes every year.
As the world’s third largest concentrating solar power (CSP) plant and the first of its kind built in as many as 17 years, Nevada Solar One has scripted a renewable-energy success story. It has the potential even to compete with conventional power plants that use fossil fuels.
Nevada Solar One power plant makes use of a proprietary technology for tracking the location of the sun and concentrating the rays during hours of peak demand. There are 760 parabolic concentrators consisting of over 182,000 mirrors. They focus the rays of the sun on to as many as 18,240 receiver tubes. Fluids circulated through these tubes get heated to 735 degrees Fahrenheit and in turn transfer the heat to water to produce steam for driving a conventional turbine. The turbine is coupled to a generator to produce electricity.
Nevada Solar One created more than 800 jobs during the construction stage and about 30 permanent jobs in the operation stage. Sierra Pacific Resources and Nevada Power Company purchase all the power generated under long-term power purchase agreements.
Challenges Posed By CSP Systems in the Australian Context
Blistering sunshine, direct normal insolation in the 15 degrees to 35 degrees lattitude, is what makes it appealing for Australia to adopt the CSP technology.
By definition, top solar locations (remote deserts) do not match with the existing transmission and distribution infrastructure. It calls for installation of expensive transmission lines as Australian networks have been developed to deliver electricity from generators located beside gas, coal and hydro resources.
CSP generating systems work most efficiently only during the daylight hours. Therefore, it is not possible to rely upon them as primary sources of electrical power. Further, they cannot cater to peak demand hours.
CSP without storage systems is two times more expensive than large-scale photovoltaic systems. Heat storage systems are far more efficient compared to those that store electricity. However, even they may not be of great help if overcast conditions exist for several days.
The payback time for CSP systems is longer since they cannot generate electricity continuously.
CSP systems are extremely expensive. This one drawback outweighs all the benefits that they could bring. A report published by the Australian Solar Institute estimates the levelized energy cost for utility-scale solar thermal power as A$250/MWh.
Finally, it is not possible to use small dish/engine systems in backyards for powering homes since the cost of building a system with mirror alignment and Stirling engine is extremely high.
Since the 1980s, CSP systems have been in existence and technological advances have helped them to become more efficient. However, the fact that these systems can supply clean energy under appropriate conditions cannot be denied.