1. A method comprising: receiving, by a computer system from a user, first information pertaining to an energy generation system to be installed at a customer site; determining, by the computer system, an electrical design for installing the energy generation system at the customer site, the determining being based on the first information, second information retrieved from one or more external data sources, an electrical data model, and a decision tree modeling an electrical design process, the decision tree comprising a series of decisions and decision outcomes that guide the computer system on what electrical components are needed to implement the energy generation system and how the electrical components should be interconnected, the electrical components comprising at least one inverter, one or more alternating current (AC) components, and one or more direct current (DC) components; and generating, by the computer system, an installation diagram illustrating the determined electrical design.