Configuration Optimization of a Photovoltaic Power Plant in Relation to Cost and Performance

Abstract

The purpose of this paper is to examine the economic benefits of single-axis tracking photovoltaic (PV) power plants for a variety of locations with varying solar resources. Although the photovoltaic industry has been around for decades, the industry has changed dramatically in the past few years. A confluence of overproduction of panels and an economic recession have caused a precipitous drop in panel prices. Additionally, as tracking systems have matured, they have become more acceptable — technically and economically. With all these changes, it is not clear today if and where tracking is appropriate. This paper is to gauge the difference between a tracking and non-tracking configuration of a PV plant. For the purpose of this study, a net 20 MW alternating current (AC) PV plant was assumed to be developed at three different locations: California, Colorado, and New Jersey. The same panel of a moderate efficiency was picked and was used at each site. While a panel is not usually decided before development, a panel of typical characteristics was chosen so that prospective panels’ costs and efficiency could be assessed concerning tracking using a qualitative analysis. Levelized cost of energy (LCOE) of each site was determined using the Life-Cycle Cost Analysis methodology. For fixed mounting structures, the tilt of the panel was optimized based on the respective weather conditions to maximize production. After the tilt was decided, an economic sensitivity study taking shading and land prices into account was used to find the most economical spacing between mounting structures. For tracking, horizontal single axis tracking was assumed, and spacing was optimized as described above. The results of the study show that the benefit of tracking increases with the strength of the solar resource. In Newark, New Jersey, tracking raised the LCOE. In Daggett, California, tracking lowered the LCOE. In Boulder Colorado, the difference in LCOE was not appreciable. The study also showed that the most economical fixed PV power plant used less land on a capacity basis at each site. However, tracking plants, regardless of location or solar resources, produced more energy (kWh) per acre of land and could be described as more efficient on a land use basis.