Economic evaluation of energy produced by a bifacial photovoltaic array in the era of time-of-use pricing

Electric utility companies curb their system peak power demand through numerous Demand Response (DR) programs, such as the Time-Of-Use (TOU) rates where the cost of energy is typically much higher during the peak period and lower for the rest of the time relative to the standard flat rate. Meanwhile, a vertically installed West-facing bifacial PV array is expected to provide an advantage over a conventional South-facing orientation as it receives more sunlight during the period of high energy cost. This article evaluates the performance of a 1 kW bifacial PV array under different orientations while considering two energy rate options provided by the local power provider (a flat fixed rate and a TOU rate). Actual data collected during the 2011 and 2012 summer months, and numerical simulations using typical meteorological year data of the local region suggest that re-orienting the array to face west during the summer period does not result in any significant cost savings.