Capacity Expansion for Utility Scale Single Axis Tracked PV Systems with Sub-Optimal Performance

Solar photovoltaics (PV) are a promising candidate for utility-scale use due to the low cost per mWh of silicon-PV and large available solar resource in the continental United States. At the utility scale, the last few years have seen a massive increase in deployment of Single Axis Trackers (SATs), which rotate a PV module east-west so that it always faces towards the Sun. However, the effect of SAT failure on the costs of utility scale PV is not well studied, mainly because data on tracker failure in field is either nonexistent or proprietary. We simulate tracker failure in a capacity expansion model to quantify the costs of theoretical failure modes, including tracker stall, improper backtracking, and other reasonable failure conditions. This work presents a capacity expansion model that quantifies the losses incurred by these failures, in terms of costs of required additional generation to meet future demand. We rank failures from most costly to least, and provide operational recommendations to operators to mitigate potential failure.