As part of the right-of-way permitting and related environmental impact statement process, the BLM analyzed the use of either photovoltaic or concentrating solar thermal technology for the Sonoran Solar Energy Project.
Photovoltaic Solar Technology
Sunlight is composed of photons, or packets of solar energy. When photons strike, and are absorbed by, a photovoltaic cell they generate direct current (DC) electricity. This phenomenon is known as the photoelectric effect. The direct current electricity generated by a group of photovoltaic cells (collectively called a photovoltaic panel), flows from the panels into a collection system. Power inverters conver the DC electricity into alternating current (AC) electricity, which is commonly used by electric utilities and in homes and businesses. The AC electricity is then boosted to transmission voltage for delivery onto local transmission lines that local utilities use to deliver the energy to customers.
The photovoltaic solar field consist of photovoltaic panels, sometimes referred to as "modules," that are grouped together in numerous arrays. Each array is electrically connected to a power inverter and each power inverter is electrically connected to a single project substation.
The photovoltaic arrays are oriented north-to-south based on the mounting structure design. A "tracker" mounting system can be used to allow the arrays to track the sun's motion during the day. These tracking mechanisms maximize the solar energy conversion efficiency by keeping the modules perpendicular to the sun's energy rays throughout the day. A "fixed" mounting system can also be used. In this application, the arrays are set in a single postion and do not move at all. This is a less complicated mounting system and requires less space to construct but is generally not as efficient.