Existing Customers may remain over a legacy tariff below its regulations, and other utility territories might have different arrangements. That is a billing coverage, not an installation rebate; a battery can retail outlet solar power for later on use in place of exporting it. Certification isn't really a business requirement https://www.americanarraysolar.com/report-38-percent-energy-cfos-say-solar-will-be-the-most-dominant-form-of-alternative-energy-by-2023/