Under this model, the solar system is purchased outright with upfront capital investment. The system owner bears the initial cost but enjoys the benefits of reduced electricity bills and potential long-term savings. There are no ongoing payments, and the system owner is responsible for maintenance and operation.

Under the RESCO model, a third-party developer installs, owns, and operates the solar system on the customer's premises. The customer enters into a long-term agreement (typically 10-25 years) to purchase the electricity generated by the system at a predetermined rate. The RESCO provider is responsible for financing, installation, maintenance, and operation of the system, while the customer benefits from reduced electricity costs without upfront investment.

A PPA is a contract between a solar system owner (developer or financier) and a customer (typically a business or institution). The customer agrees to purchase the electricity generated by the solar system at a fixed rate per kWh over a specified term (usually 10-25 years). The PPA provider is responsible for financing, installing, operating, and maintaining the system.

PPA agreements often include provisions for system performance guarantees, insurance, and escalation rates for electricity prices over time. Each financing option has its advantages and considerations, and the choice depends on factors such as financial goals, risk tolerance, and available resources. It's essential for customers to carefully evaluate these options and consult with solar experts to determine the most suitable financing model for their specific needs.