The Federal Income Tax Credit is available on one's own primary home, and maybe not on residential rental property. So perhaps there is a way for a parent give an array on the home of a son or daughter, and still take a tax credit. Many installers lease systems to the customer, sometimes financed by a third entity who technically own the system and takes the tax credit. Often these deals are complicated and may not be beneficial to the family hosting the system.
Is there a reason a parent can't pay to install the system which technically is leased on very beneficial terms to their kids...maybe with two year terms at $1/month and at 0% interest? SEIA has a model lease agreement, written in Word so it can be modified to whatever terms are good for both the parent and kid:
Lease Agreement for Residential Customers (Disaggregated)
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William Dorsett
Flint Hills Renewable Energy & Efficiency Cooperative
Manhattan KS
mail@fhreec.org------------------------------