So what do a company’s marketers and salespeople mean when they say ‘free solar panels’? Usually, they are referring to solar leases and power purchase agreements (PPA’s). Under these solar financing arrangements, a solar company will put a solar system on your roof at no up-front cost to you. This sounds great – you get to say that your home is powered by clean energy, and can even point to the solar panels on your roof to prove it.

But the reality is that you do not technically own the system, and the solar energy the panels produce is not free. Under solar lease agreements, ownership is retained by the solar company, and you pay for the electricity it produces. In essence, the company has built a small power plant on your roof and is selling you the electricity.

https://news.energysage.com/free-solar-panels-really-free/