House with solar panels on the roof

Even if you finance the purchase (take out a loan) you own the system.  The loan payments can be structured like a lease (no money down), but you own the system from the get-go and are eligible for the 30% Federal Tax Credit or any other benefits, that goes to the owner of the solar system.  Everything considered, it is very likely that you will have paid off the loan/purchase with only half the cost of a lease/PPA.

Some banks now offer renewable energy loans that can have lower rates than a home equity loan.  For instance, Umpqua Bank has their Green Street Lending that has been quite successful in providing such a loan.

Property Assessed Clean Energy (PACE) Loans is another option.  The loan is NOT tied to your credit score, basically requires you to have at least 10% equity on the house, and is paid twice a year as a part of your property tax.  It takes only minutes to find out how much your property is eligible for by simply typing in your address.  Some popular ones includes the CaliforniaFIRST program and the HERO program.