The international push for greater dependence on renewable energy sources sparked significant growth in the number of solar power projects in 2011. In the Southwestern United States, the nation's most arid climate, solar power can reach maximum efficiency potential and is hailed a great solution to reduce carbon emissions and pollution. In Germany, solar power output increased by 60% in 2011. In nations such as India and China, economic and population growth has facilitated the growth of solar energy plans as solar facilities simply add to the grid instead of replacing other energy sources. The largest completed project in New England, a 44 MW proposed project in Peru, and additional large-scale projects in Canada and France made 2011 a great year for solar power. These recent advances have reintroduced a debate surrounding solar power efficiency that first received media attention about 4 years ago. Solar facilities require massive amounts of water. Facilities that use photovoltaic panels require approximately 16,600 gallons per megawatt annually. Solar facilities that utilize wet-cooling solar thermal tactics use more than 2 million gallons per megawatt annually, and even more water is necessary for cooling in particularly hot regions where evaporation occurs more rapidly. On average, solar parabolic troughs use three times as much water as a coal power plant and nearly twice as much as a nuclear plant per megawatt hour. In a dry, sunny region where solar power is often seen as most logical based on foreseen efficiency, it can prove impractical to expand an industry that needs so much of a scarce resource.
Much of the need for water use on solar arrays does not come from operating the facility, but instead from cleaning the panels. Solar photovoltaic panels can lose up to 3% efficiency due to dust collection, which is a visible problem in the desert. The bigger the plant, the more power lost with the presence of dirt and dust. Dusty cells are washed using tap water hoses often moved and operated from trucks. This must be done at least three times a year to keep the facility at maximum efficiency.
This contentious issue has been largely ignored in reports of new solar projects, especially in arid regions where solar power is of growing popularity. Although solar energy has several environmental benefits, many wonder whether it is wise to develop an industry without recognizing the consequences of increased water scarcity. Experts in Arizona, California, and Nevada have pushed for the development of solar facilities that use less water and a cost-benefit analysis of water use in solar facilities. As water conservation is directly linked to sustainability and what is green, the overuse of water resources to maintain solar facilities questions their feasibility as a green energy solution. We must ponder whether new solar power projects are really benefiting people and the environment as much as they advertise, or whether further advancements to increase water efficiency of solar facilities is necessary, especially before they are developed in water-scarce regions. Solar power has great potential, but must we perfect the technology and its efficiency before rushing into large-scale implementation? The 2011 year of say go to solar would say no.
Photo Credit: "Solar Panels" by spanginator from Flickr used under the Creative Commons Copyright
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