Does a PV Tracking System Make Sense for Co-Ops?: An Analysis of the Value of Off-Azimuth Arrays and Single-Axis Tracking on Peak Demand Matching for Electric Distribution Co-Ops

摘要

Most utility-scale PV systems are designed to optimize annual energy output. This is especially true with power purchase agreements (PPAs) which focus entirely on the total cost of energy. Utilities, however, value energy differently, depending on the time of day. For example, utilities are often subject to demand charges based on peak usage which often occur during the afternoon on hot summer days. Solar that provides power during that peak would thus provide more value than at other times. This paper evaluates the system performance of off-azimuth designs (facing southwest and west) and single axis tracking compared with optimum due south orientation, with an eye on performance during afternoon "peak" periods. A discussion of the potential economic benefits is provided, along with a sample economic analysis of the differential value of array options. The results show that off-azimuth systems can provide significant demand reduction benefits with a penalty of reduced annual energy production. Tracking systems can provide both increased energy and further demand reduction for afternoon peaks typical of distribution cooperatives. Economic benefits are highly dependent on both the location and the procurement rate structure of a particular co-op.