Even though new credits have been terminated, your prior credit will continue to carry forward until you use it up.
As mentioned, if you have retirement accounts, this might be a good opportunity to convert IRA or 401k funds to a Roth IRA or in-plan Roth 401k (if your employer offers that option). That way you pay the tax on the money now, and do not have to pay more tax when you withdraw.
For example, in the typical middle class tax bracket of 22%, a $10,000 conversion will cost $2200 in taxes. If you had a $10,000 solar credit to use up, you could convert $45,000 of pre-tax IRA or 401k funds to a Roth IRA or Roth 401k, and it would be basically tax-free, because it would go against the credit.
