The Garage of the Future: Maximizing the Economic Value of Solar Panels

The research presented in this paper considers two factors that have an impact on the economic value of a residential PV plant to both the residential owner and to the utility. These factors are the residential energy billing method and panel orientation. The research was based on twelve months of production data from a residential grid connected PV plant located in San Antonio, Texas. The plant, used as the baseline, is connected to the local grid using a net metering system. The actual production data were used to estimate revenue under constant rate and time-of-use billing and as if the plant was oriented with a westerly-tilt. When considering the economic value to the utility, estimations of utility generation costs were made based on Texas ERCOT MCPE prices. The estimated utility production costs were applied to the baseline plant output and the plant output with a simulated 30° western tilt. The results showed that except for two months where the on-peak energy production costs were unusually high, the economic value of the baseline PV plant was reduced by a 30° western tilt. It is important to remember that ERCOT prices are only representative of the highest utility daily production costs. The actual increase in economic value to the utility from a PV plant westerly tilt will be a direct function of the difference of utility production costs between off-peak and on-peak times, specifically during times of peak utility load.