Principal method of financing and strongly similar to conventional bank financing, only more flexible.
Similar to a Finance Lease, but when a business cannot take advantage of available tax incentives, or when you want to pay for a system with operating dollars, not capital dollars. It is essentially a "rental" contract with fixed terms and conditions. The Lessor gets depreciation and tax incentives. The lease can be considered "off balance sheet" for lessee.
A Power Purchase Agreement, or PPA, is a long-term agreement to buy power from a company that produces electricity. The PPA company, using its own source of funds, builds a solar energy facility on a customer's site and maintains and operates the facility for 15 years or longer. This facility generates reliable, long-term clean energy for use by the customer. Under the terms of a PPA, the investor assumes the risks and responsibilities of ownership when it purchases, operates, and maintains the turn-key facility. They provide preventative maintenance services, repair any faults, monitor the energy production and the system's health and well-being. The customer just runs their businesses as usual, without any of the headaches of owning a power plant. At the end of the PPA term, the facility can be purchased by the customer at fair maket value or the PPA can be renewed on favorable terms. The PPA enables the customers (and our world) to benefit from the use of "green" energy, while still receiving some of the benefits of ownership (lower and/or "hedged" electricity costs, positive public image, etc. ) and allows them to spend their capital budget on their core businesses.