This article discusses the opportunities and obstacles that beset concentrated solar power in this low-carbon economy.
In view of the Copenhagen Accord agreed upon by world leaders in December 2009, a serious, concerted effort by governments and industry has formally crystallized to search for clean energy solutions. These solutions are aimed at mitigating greenhouse gas emissions to address climate change while simultaneously addressing the huge energy appetite of a fast growing global population pursuing an energy-intensive, high quality of life.
One promising clean energy solution is concentrated solar power (CSP), also known as solar thermal electric power. CSP refers to the sun radiating its heat energy on mirrors spread over thousands of acres of land in order to focus the sun’s heat on powering steam turbines that, in turn, generate electricity (Schmidt, 2008).
The most established CSP plant design is the parabolic troughs power plant. It is comprised of curved troughs made of mirrors which run parallel to the ground. The sun’s energy bounces off the mirrors toward a central tube filled with synthetic oil, which is heated to about 600°F. The heated oil flows into a heat exchange system that transfers heat from the oil to water. The resultant steam runs a turbine cycle to create electricity that feeds directly into the local power grid (Schmidt, 2008).
First, the sun's energy used by a CSP plant is free, clean, renewable and available everywhere in the world (Pembina, 2010). CSP plants produce clean electricity without any greenhouse gas emissions and thus are beneficial to the environment (Tyner, Kolb, Geyer, & Romero, 2001).
Second, a CSP plant produces electricity at roughly the same cost per kilowatt-hour comparable to the cost of coal-fired and nuclear power plants. A CSP plant is more cost- effective than solar photovoltaic (PV) systems because PV panels cost thousands of dollars to install in homes and buildings (Schmidt, 2008) due to the high cost of solar cells and energy storage (Tyner et al., 2001).
Third, a CSP plant uses commonly available materials (Pembina, 2010) such as glass, concrete, steel and turbines and it uses relatively conventional technology (Tyner et al., 2001). Moreover, the majority of the CSP plant hardware can be built locally in a specific country using local labour. Alternatively, constructing PV systems is very expensive because of the high cost of building special-purpose facilities to manufacture solar cells (Tyner et al., 2001).
Lastly, a CSP plant is modular and can be “hybridized”. It can provide energy on its own, be connected to a grid or be combined with other energy sources (Pembina, 2010). Because of its thermal nature, a CSP plant can be “hybridized” or operated with fossil fuel as well as solar energy. Hybridization has the potential to dramatically increase the value of CSP technology by increasing its availability and dispatchability. This feature lowers overall costs by making more effective use of power generation equipment. It also mitigates technological risk by allowing conventional fuel use when needed (Tyner et al., 2001).
First, solar energy is not always available because of its diurnal nature. Thus, it needs to be stored to be a continuous source of energy (Pembina, 2010). Instead of releasing excess heat into the air, a CSP plant stores it in tanks of molten salt. During the evening, or when it is cloudy, that heat can be released to run the steam turbine for 6 hours or more, depending on electricity demand (Schmidt, 2008).
Second, a CSP plant usually requires an enormous amount of land (Boyle, 2004). One CSP project required 130 acres of mirror field to produce 10 megawatts of electricity (Winters, 2008). Moreover, locating actual sites to set up a CSP plant can be challenging as only sunny places, such as deserts near large urban electricity demands, can generate the high temperatures necessary for thermodynamically efficient operations (Boyle, 2004).
Third, the construction of a CSP plant is capital-intensive and requires the payment of upfront capital costs. This is onerous and can deter private investment in CSP development. Innovative private financing is needed to spread the capital costs over several years so that they can be paid out of income or savings received. Governments also need to step up their participation by providing financial incentives and friendly taxation policies to improve the economic competitiveness of the CSP market. (Pembina, 2010).
Lastly, the public perception that CSP technologies are new, risky and pose as possible threats to existing technologies and interests needs to be changed. Thus, governments need to accelerate their support for research, technology development and demonstration projects in order to alter such public perception. Governments can do this by establishing stable, long-term regulatory policies that will facilitate the robust development of the CSP industry (Tyner et al., 2001).
Indeed, the future of CSP holds great commercial promise in this post-Copenhagen era. Because of the plethora of opportunities and benefits that CSP provides, obstacles that beset its robust development can be addressed with the synchronized efforts and strong political will of both government and industry in the context of this emerging low-carbon economy (Luzzi & Lovegrove, 2004).
Of all the renewable technologies available for large-scale power production today and in the coming decades, CSP is one of few with the exciting potential to produce carbon-free electricity (Tyner et al., 2001) aimed at mitigating greenhouse gas emissions to address climate change while simultaneously addressing the huge energy appetite of a fast growing global population.
Boyle, G. (2004). Renewable Energy: Power for a Sustainable Future, second edition. Oxford University Press, 51-62.
Luzzi, A., Lovegrove, K. (2004). Solar Thermal Power Generation. Encyclopedia of Energy, http://www.sciencedirect.com/science/article/B7GGD-4CM9GC0-C1/2/5ec7f3ddb2ab612b43066baf4e214f4d) (accessed April 23, 2010)
Schmidt, C. (2008). Sunlight on mirrors. Environmental science & technology, 42(19), 7031.
The Pembina Institute, “Energy Source: Solar Energy”, The Pembina Institute website, http://re.pembina.org/sources/solar (accessed April 23, 2010).
Tyner C., Kolb, G., Geyer, M., & Romero, M. (2001). Concentrating Solar Power in 2001: An IEA/Solar PACES Summary of Present Status and Future Prospects, 1-14.
Winters, J. (2008). The sunshine solution. Mechanical Engineering, 130(12), 24-29.