If the solar panels weren't leased, they'd just be coverage A. Since they are leased/rented to the insured, you look to the liability coverage since solar panels aren't really personal property. The liability section excludes property damage to property rented to, occupied by, or used by or in the care of the insured, except for fire, smoke or explosion. There is a little bit of coverage under the additional coverage Damage to Property of Others, but this is limited to $1,000. 

You could add the additional insured endorsement, HO 04 41, which makes the listed person or organization an insured with respect to coverages A and B, dwelling and other structures, and E and F, personal liability and med pay. Of concern is the extension of liability coverage however the endorsement states that E and F apply only with respect to injury or damage arising out of the ownership, maintenance or use of the residence premises. Other than that, there are no endorsements that fit your scenario or other ways to provide coverage.