Throughout the US, the running costs of solar-tracking photovoltaic units vary greatly dependent on the weather and how much the unit is exposed to the sun throughout the year. In Nevada and California, and other areas of the western United States which receive more direct solar radiation, single-axis PV panels track the sun’s path from east to west – a technology that is becoming increasingly cost-competitive with burning fossil fuels to generate electricity.
In states west of the Mississippi River, fixed-tilt solar PV units accounted for just 37% (3,904 MW) of total solar PV unit capacity in 2015, and single-axis solar PV units accounted for 56%. In comparison, single-axis units in the eastern region accounted for just 19% of solar PV capacity in the eastern United States.Fixed-tilt solar PV units accounted for 80%, or 2,468 MW of capacity, of all utility-scale solar PV units operating in 2015 in the eastern United States (i.e., east of the Mississippi River), according to the EIA’s Annual Electric Generator Report.
Comparing generation costs for different energy sources, the EIA has historical data on the average annual operation, maintenance, and fuel costs for all power plants that are operational throughout the United States.
The most recent available projections and estimates for different types of power plants are in Levelized cost and levelized avoided cost of new generation resources in the Annual Energy Outlook 2016, which includes estimated costs in dollars per megawatthour (mWh) based on a 30-year cost recovery period for various types of power plants that start operation in 2018, 2022, and 2040.
Technology choices
As for solar-tracking technologies, the two main types are solar radiation are direct-beam radiation (which comes from sun to earth in a straight line) and diffuse radiation (whereby is light that has been scattered by the atmosphere).
Financial considerations not only affect the technology choice but also whether the investor goes for fixed-tilt mounting or more complex solar-tracking technology. Fixed-tilt units are cheaper to install than solar panels with tracking technology. Single- and dual-axis tracking units require additional acreage to install, and the tracking systems themselves are more expensive.
Tracking systems, while more expensive, can however produce more electricity.
The PVWatts calculator developed by the National Renewable Energy Laboratory estimates that, over the course of a year, a 10-kilowatt PV system in Los Angeles, California, using a single-axis tracking system will produce 21% more electricity than a system tilted at a fixed 20 degrees. A dual-axis tracking system in the same location would produce 31% more than the fixed-tilt system.