The service estimates the expected performance of photovoltaic (PV) energy systems suitable for residential and small commercial applications. Simulations estimate energy production from PV cells, given a location and other operating conditions, along with cost savings. Cost data assume that a system is connected to an existing electrical power grid rather than free-standing. API methods support submission of a location, specified as address or latitude and longitude, along with system operating parameters such as generating capacity, solar tracking functions, and operating times including daily schedules. Cost savings parameters include system initial cost, maintenance cost and deterioration over time, financing costs, tax effects, and related variables.