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During their operation, solar photovoltaic (PV) panels represent the environmental ideal for energy production, generating clean electricity from renewable and abundant sunlight without any associated CO2 emissions.  However, much energy can go into materials processing, manufacturing, installation, and end-of-life decommissioning of a solar cell.  The ratio of the energy produced over the lifetime of the solar panel to the energy input to its construction and decommissioning is called the energy returned on energy invested (EROI), and is an important metric.

Decommissioning at the end of a solar panel’s life is also important because 1.) some solar panels, like First Solar’s CdTe thin film solar cells, contain toxic materials that could be harmful if not recycled or disposed of properly and 2.) the sheer mass of solar panels needed to power the planet’s electricity needs are very large.  In the article below, it is noted that the amount of solar panels needed to produce all of the world’s electricity needs would cover the surface of Spain and weigh approximately 150 million pounds.

http://seekingalpha.com/article/3086616-dark-side-of-the-sun-solar-power-and-global-electronic-waste

First Solar used to have a pre-funded recycling program, in which it guaranteed that it would remove and recycle it’s solar panels at the end of their life. Unfortunately, this policy has been significantly relaxed in recent years.

As engineers, we need to consider not only in-service performance metrics of solar panels such as efficiency and life-time, but also end-of-life metrics such as recyclability, which can greatly influence an overall life cycle analysis and environmental impact. The selection of the materials we use, and how we combine them with other materials at the cell and/or device level, can be very important!

280 MW California flats solar project in California (http://www.firstsolar.com/en/about-us/projects/california-flats )

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