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First Solar Investigates Water Footprint in IEEE Journal of Photovoltaics

Posted 8 March 2013 5:18 PM by First Solar

First Solar’s technical article titled “Life Cycle Water Usage in CdTe Photovoltaics” has been published in the IEEE Journal of Photovoltaics, a leading international scientific journal. The paper was written by First Solar’s Parikhit Sinha and Amy Meader along with SmartGreenScan’s Mariska de Wild-Scholten. The article documents First Solar’s water footprint over the life cycle of a cadmium telluride photovoltaics (CdTe PV) installation. While energy security and climate change have been important drivers for renewable energy adoption, water security provides an additional driver. For example in the United States, thermoelectric power plants have recently accounted for over 40% of total freshwater withdrawals from all sectors, even more than for agriculture. This energy-water nexus associated with traditional energy sources can be a potential concern, particularly in water-stressed regions. Because solar PV uses little to no water during operation, it provides a promising path forward for addressing the energy-water nexus.

Water Displacement Graph

Fig. 1. Major contributors to life cycle water withdrawal in CdTe PV. For BOS mounting structures, a range of 30-60 year lifetime is evaluated.

Life cycle water withdrawal for CdTe PV ranges from approximately 382-425 L/MWh, with only ~12% from direct on-site usage for manufacturing, construction, and recycling. The remainder is related to indirect water withdrawal from the use of grid electricity and raw materials throughout the product life cycle. For perspective, fossil-fuel thermal power stations withdraw 10 to 500 times more water than CdTe PV systems during just the operational phase of their life cycle. When deployed in the U.S. Southwest, a CdTe PV array can provide net displacement of life cycle water withdrawal of over 1,700-5,600 L/MWh relative to grid electricity. First Solar’s historical deployment of over 6 GW of CdTe PV modules translates to annual avoidance of over ten billion liters of water associated with grid electricity, based on world averages.

Although life cycle water withdrawal by CdTe PV is low in comparison to most other electricity generation sources, First Solar has developed a manufacturing water balance to help further reduce water withdrawal during manufacturing and find applications to reuse water. Other life cycle opportunities include alternatives to water use for dust suppression during project construction, advanced site preparation techniques to reduce dust generation during project construction, and dry methods for module cleaning during project operation in dust-prone climates.

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