On the panel side just about anyone. However if you are looking at battery’s storage there are several including Generac who acquired a third party. I did some comparisons between the generac storage and the PW and the PW seemed to be a better value, especially when paired with the solar install for discounts and tax rebate eligibility.
I don't know if I'd want to be between a customer and Tesla....While I love Tesla’s specs and prices in energy products from my view they are unobtainable. As a solar company we have been trying to become a certified installer for Tesla and after 9 months 5 applications and 4 phone calls I can’t even get the courtesy of a confirmation call or email. I tried to push the issue by personally trying to buy a PowerWall for 7 month now with the ONLY response is that we do not currently serve your area.
Their communication process is terrible.Why not it has worked well installing wall chargers.