As long as you own your solar energy system, you are eligible for the solar tax credit. Even if you don't have enough tax liability to claim the entire credit in one year, you can “roll over” the remaining credits into future years for as long as the tax credit is in effect. It is important to mention that now is the time to act, the federal tax credit reduces from 30% to 26% in December 2019. The following year it reduces down to 22%.
Disclaimer: While we are experts on Solar installations, we are not tax experts. Individual situations may vary, please consult a tax professional before filing for your solar tax credit.