Renewable energy is the dream of countless environmentalists and active citizens. Adopting hybrid electric vehicles and domestic sources of sustainable energy are some of the goals of renewable energy. The increasing price of energy derived from crude oil and concerns regarding energy security have stimulated investments in sustainable resources such as solar energy.
The search for and extraction of oil are negatively impacting the environment around oil platforms. Offshore drilling platforms report spills every year that kill an estimated 315 thousand birds per platform.1 Additionally, the waste fluids ejected from the drilling process harm marine life that rely on filter feeding; these pollutants then travel up the food chain in a process called biomagnification.2-4 Research and development efforts in renewable energy sources promise to minimize these harmful practices by reducing society’s dependence on oil.
One such alternative to oil-derived energy lies in residential and commercial photovoltaic solar panels that convert sunlight into electric current. Depending on the weather, the sun provides between 3.6—6 kWh/m2 (kilowatt-hours per square meter) per day in the U.S.5 Homeowners are beginning to capitalize on this source by installing residential, small-scale “rooftop panels,” which are labeled as photovoltaic (PV) systems. These systems work to create electric current by harnessing the excitation of electrons from sunlight. These systems are becoming commonplace as their cost continues to decrease. In 2011, the cost of installing PV systems was 11—14% lower than that in 2010, and in 2013 prices were even lower.6
The most widely adopted material in these products is silicon, a material known for its conductivity. Development in conducting materials and manufacturing methods has greatly accelerated since the first application of silicon, improving energy collection. Now, total global grid-connected systems produce seven million kW.7 As the average American home uses between 2—5 kW per year, this grid system can support two to three million U.S. homes.8 A second viable option for solar energy is Concentrated Solar Power (CSP). Known as “power towers,” CSP uses mirrors to concentrate the sun’s rays, generating enough power to heat water and operate a turbine. Water is not the only fluid utilized: in a parabolic mirror system, oil is heated to 400 °C to convert water into steam via subsequent heat transfer.9
CSP plants are expanding globally; they are expected to produce a total of 5000 MWh (megawatt-hour) by 2015. This is an increase from the 2011 figure of 1000 MWh. As one might expect, these towers are set to be installed in sunlight-rich areas, with the majority of this planned construction taking place in California. Towers will also be installed in China, Israel, South Africa, and Spain.7 Typical CSP systems today can generate one MWh of electricity for every 4—12 square meters of land space, which, according to the Royal Academy of Engineering Ingenia, “can continuously and indefinitely generate as much electricity as any conventional 50 MW coal- or gas-fired power station.”10 This is relatively small, given that the average U.S. residential home occupies about 405 square meters. The average 1000 MW U.S. coal-fired power plant requires 1—4 square kilometers of land space, translating into 6—18 GWh (m2/gigawatt-hours), or 4—20 square meters per GWh. However, including the amount of land needed for mining and waste disposal, this figure can include an upper limit of 33 m2/GWh.11 This factor of land efficiency leads to these newly installed CSP plants to produce one kWh worth of electricity for $0.10—0.12, given the costs of installation and maintenance as well as other fixed and variable costs. In Houston, Texas, rates for oil-derived electricity can range from $0.08—0.15/kWh, which makes CSP a very competitive alternative.10
Opposing arguments based on the high cost of photon-collecting technology and the intermittency of solar rays are losing ground. In the U.S. alone, the PV market has grown considerably. For example, California experienced a 39% growth in residential PV system installations in the fourth quarter of 2012 (Fig. 1).12 Thus far, the cost of these systems has declined over 30% in the past few decades, and the U.S. Department of Energy’s (DOE) SunShot Vision Study is attempting to further reduce costs by 75%. With this initiative, the DOE plans to “meet 14% of U.S. electricity needs via solar energy by 2030 and 27% by 2050.”13 It is believed that this goal will be possible once solar electricity generation reaches the cost of $0.06/kWh, near the range of current fossil-fuel based generation methods.13 The SunShot Vision Study has implemented a “Rooftop Solar Challenge” aimed at improving the logistical requirements of installations in order to apply its initiative to states across the U.S.
Applications for solar energy can range from using solar cookers with the CSP model to portable solar chargers for personal electronics. These forms of energy can be scaled to any size, and their full integration into society is only hindered by the current dependence on oil. To make energy production sustainable, solar technology must be further developed and implemented. Statistical models need to be considered, academic and industrial research needs to be funded, and a united effort in adopting these technologies needs to take place. Significant progress has been made in homeowner PV system adoption and the DOE’s SunShot Vision, which serve as testaments to the viability of a sustainable energy economy. When comparing the advantages of oil against the advantages of solar energy, it is clear that solar energy has the potential to provide more efficient and environmentally friendly results. These alternatives still need technological advancement, proper location, and governmental support; once these are completed, solar alternatives will be able to meet our energy needs. Although we as a society may find ourselves too dependent on oil, there is hope for a more sustainable, responsible, and environmentally friendly world.
- Tasker, M. L. et al. The Auk. 1984, 101, 567-577.
- Wiese, F.K. Marine Pollution Bulletin. 2001, 42, 1285-1290.
- Wiese, F.K.; Robertson, G. J. Journal of Wildlife Management. 2004. 68, 627-638.
- Ocean Discharge Criteria Evaluation; General Permit GMG290000; US EPA: 2012; 3. http://www.epa.gov/region06/water/npdes/genpermit/gmg290000_2012_draft/ocean_discharge_criteria_evaluation.pdf (accessed Feb. 1, 2014).
- George Washington University GW Solar Institute. How much solar energy is available? http://solar.gwu.edu/FAQ/solar_potential.html (accessed Feb. 1, 2014).
- Chen, A. Lawrence Berkeley National Laboratory. The installed price of solar photovoltaic systems in the U.S. continues to decline at a rapid pace. http://newscenter.lbl.gov/news-releases/2012/11/27/the-installed-price-of-solar-photovoltaic-systems-in-the-u-s-continues-to-decline-at-a-rapid-pace/ (accessed Feb. 1, 2014).
- Hamrin, J.; Kern, E. Grid-Connected Renewable Energy: Solar Electric Technologies; United States Agency of International Development (USAID): Washington, D. C. http://www.energytoolbox.org/gcre/mod_5/gcre_solar.pdf (accessed Oct. 28, 2013).
- Solar Energy Industries Association. Solar Energy Facts: Q3 2013. http://www.seia.org/research-resources/solar-industry-data (accessed Feb. 1, 2014).
- Concentrating Solar Polar (CSP) technologies. http://solareis.anl.gov/guide/solar/csp/ (accessed Feb. 3, 2014).
- Müller-Steinhagen, H.; Trieb, F. Concentrating solar power: a review of the technology. Royal Academy of Engineering, Ingenia. 2004, 18, 43-50.
- Fthenakis, V.; Kim, H. C. Renew. Sust. Energ. Rev. 2009, 37, 1465-1474.
- Solar Energy Industries Association. U.S. Solar Market Insight 2013. http://www.seia.org/sites/default/files/4Y8cIWF6ps2013q1SMIES.pdf?key=58959256 (accessed Nov. 10, 2013).
- U.S. Department of Energy. SunShot Initiative. http://www1.eere.energy.gov/solar/sunshot/about.html (accessed Nov. 10, 2013).
- U.S. Department of Energy. Updated capital cost estimates for utility scale electricity generating plants. U.S. Energy Information Administration: Washington, DC, 2013. http://www.eia.gov/forecasts/capitalcost/pdf/updated_capcost.pdf (accessed Nov. 7, 2014).