A key challenge facing residential and small business utility customers that are considering installing PV solar is accurately estimating the impact of various PV system sizes and utility rate structures on the payback period. Most utility customers struggle to perform cost calculations necessary to optimize their return on investment on solar projects. For a typical electrical customer problem becomes hopelessly complex when all available rate structures are considered. Finding rate information is time consuming and performing calculations are tedious and time consuming.
This problem is solved using intelligent selection method which considers usage patterns, electric rate structures, and PV production estimates. This approach relies on two publicly available datasets and a DOE developed software package. These data sets are: 1) green button data(provided by the customer); 2) utility rate data (OpenEI utility rate sets); and 3) solar performance (PVWatts Beta Release).
Fusing greenbutton data with rate information would allow a customer to estimate the impact of shifting to a new rate structure (e.g., flat, tiered, demand, time-of-use, or real-time-pricing). Adding solar output data will allow the customer to identify and select the PV system size and rate structure that provides the most appropriate return on investment given each customers unique situation.
The value of this idea become apparent when one realizes that PVwatt assumes electric energy costs $0.16/kwh while the GS-2 rate is $0.14/kwh and the TOU rate varies from $0.47/kwh for power consumed during peak demand periods and as little as $0.103/kwh for power consumed at night. Depending on the customer’s energy use patterns the overall cost of electrical service could vary by 30% or more. The potential for savings is even greater if the customer is willing to install solar to displace peak demand and move to a time-of-use rate. The customer would still be dependent on the grid for non-peak(nighttime) consumption In addition, making PV solar more affordable this strategy also provides a social benefit by increasing the economic incentive for installing generating capacity that support grid peak demand.