Solar PV ROI Calculator
Built a detailed Return on Investment (ROI) spreadsheet for modeling system performance, energy, and cost savings. The spreadsheet took into consideration the variation in electric rate increase as a function actual electric usage and time period as described under the Electric Rate Analysis description to predict each customer’s individual electric rate trend. Accurate meter calculations were based on E1, E8, and EM schedules, as well as multiple dwelling units, all baseline territories, and basic, all-electric, and mixed baseline codes.
Emphasis was on configuration flexibility and simplified reporting. The tool could accommodate two meters with multiple arrays per meter and contained lookups for multiple panel and inverter types (1φ & 3φ.) It also included system loss information obtained from direct discussions with engineers at the National Renewable Energy Laboratory (NREL.) There was a correction for sun peak hours obtained from PVWATT for select zip codes. Calculations were performed for each month, including historical usage and a shading/tilt/azimuth correction from Solar Pathfinder.
Final outputs included a detailed quotation, estimated energy production, and CO2 avoided. Derived financial figures were first year return on investment (based on non-taxable and taxable investment), increase in equity, and number of years until payback.