Rozina Kanchwala / 04/02/2014
Many people know that solar photovoltaic (PV) panels emit no pollution while generating electricity and do not use fossil-fuel resources.
However, there are some questions about how much energy is required to produce the panels so they can in turn provide clean energy. This is known as the “energy payback” for solar PV cells.
Depending on the materials and technology used to create PV modules, energy payback estimates are between 1 and 4 years. This is slight, when comparing the figure against the life expectancy of panels, which is estimated to be longer than 30 years. This means a 1 to 4 year energy-input investment results in PV systems that produce clean energy for over 30 years.
The most energy-intensive part of manufacturing panels includes purifying and crystallizing the silicon. Other aspects of silicon-cell and module processing that add to the energy input include cutting the silicon into wafers, processing the wafers into cells, assembling the cells into modules, and overhead energy use for manufacturing facilities.
Additionally, PV systems avoid spewing out tons of greenhouse gas pollutants into the air. Assuming a PV system creates clean energy for 28 years, has a 2-year energy payback period and meets half of a household’s electricity, an estimated ½ ton of sulfur dioxide, 1/3 ton of nitrogen oxides, and 100 tons of carbon dioxide emissions would be avoided.
In conclusion, while energy is undoubtedly required to manufacture solar PV cells, the energy payback is short enough that it is worth pursuing solar to continue providing the world with clean energy for many decades to come.
NREL PV FAQs: http://www.nrel.gov/docs/fy04osti/35489.pdf