Concentrated Solar Power (CSP) is a technology which produces electricity by concentrating solar energy in a single focal point. This concentrated energy is used to produce steam, heat up fluids, and activate turbines that produce electricity. Today, there are many types of CSP technologies: towers, dishes, linear mirrors and trots.
What is a parabolic trough system?
Consider a parabolic trough system: parabolic troughs are large mirrors, shaped like a giant U. These troughs are connected together in long lines and will attract sun throughout the day. When the sun’s heat is reflected off the mirror, the curved shape sends most of that reflected heat onto a receiver. The receiver tube is filled with a fluid; it could be oil, molten salt, something that holds the heat well. Basically, this super hot liquid heats water in a heat exchanger, and the water turns this heat. The steam is sent off to a turbine, and from there it is business as usual inside a power plant. A steam turbine spins the generator, and the generator makes electricity. Once the fluid transfers its heat, it is recycled and used over and over, and the steam is also cooled, condensed and recycled again and again.
One big advantage of these parabolic trough systems is that the heat can be stored and used later to keep making electricity when the sun is not shining. A major advantage of the concentrated solar power plants is that they generate power best during the late afternoon – during peak demand – and can therefore potentially displace the use of fossil fuel plants that emit the greenhouse gases that cause climate change.
Growth of concentrated solar power around the world
In 2005, Concentrated Solar Power generated a mere 0.025% of global electricity. However, the concentrated solar power energy sector is growing quickly. Currently, there are thousands of MW under construction/planning in many parts of the world including Europe, the US, North Africa, and the Middle-East. Today, the United States is the world leader in installed concentrated solar power capacity, with 429 MW operating in three states. Approximately 7,000 MW from concentrated solar power is in development and the DOE projects that 2 million homes could be powered by concentrated solar power energy in the United States in 2020.
Spain has the second‐most installed CSP capacity at 182 MW and has much more under development. Israel has a demonstration power tower plant and larger trough projects in the works. Large‐scale concentrated solar power plans have also been announced in Jordan, South Africa, and the United Arab Emirates. Moreover, Egypt, Morocco, and Mexico received financial support from the Global Environment Facility of the World Bank to build parabolic trough hybrid systems and are in the implementation stages of the process. Finally, the Desertec Foundation has a highly ambitious plan and is gathering the support of companies from Germany to potentially build a 100,000 MW CSP project in the Sahara Desert and power lines across the Mediterranean Sea to connect it to Europe.
Advantages of concentrated solar power
One major competitive advantage of concentrated solar power systems is that they closely resemble most of the current power plants. For example, much of the equipment now used for conventional, centralized power plants running on fossil fuels can also be used for concentrated solar power plants. CSP simply substitutes the use of concentrated solar power instead of combustible fossil fuels to produce electricity. This means that concentrated solar power can be integrated fairly easily into today’s electric utility grid. This also makes concentrated solar power technology the most cost-effective solar option for large-scale electricity generation.
Moreover, concentrated solar power production have been shown to create more permanent jobs and stimulate the economy as compared to its natural gas counterparts. Consider the statistics from the state of California:
1. Every dollar spent on concentrated solar power production contributes approximately $1.40 to California’s Gross State Product. By comparison, each dollar spent on natural gas plants contributes about $0.90 – $1.00 to Gross State Product.
2. The 4,000 MW deployment scenario was estimated to create about 3,000 permanent jobs from the ongoing operation of the plants. For each 100 MW of generating capacity, concentrated solar power production was estimated to generate 94 permanent jobs compared to 56 jobs and 13 jobs for combined cycle and simple cycle plants, respectively.
Environmental benefits of concentrated solar power
A huge environmental benefit that should not be overlooked is that simple and non-polluting concentrated solar power technology can be deployed relatively quickly and can contribute substantially to reducing carbon dioxide emissions. Each concentrated solar power plant provides emissions reductions compared to its natural gas counterpart; the 4,000 MW scenario in this study offsets at least 300 tons per year of NOx emissions, 180 tons of CO emissions per year, and 7,600,000 tons per year of CO2.
However, the cost of these technologies is still high to enter the global market on a larger scale, and needs to decrease before such an entry can be possible. Today, concentrated solar power technology has a cost somewhere between those of Photovoltaics and wind (1W=4EUR). Consequently, additional large-scale research efforts are necessary to further advance concentrated solar power technology to make it profitable and compatible as an alternative source of clean energy.