Withholding has nothing to do with tax liability. Your tax liability is the total tax on your income for the year, regardless of how much is paid by withholding. It's based on your income minus deductions and nonrefundable credits. Here are a few things you could do to increase your tax liability.
- Earn more income.
- Increase your income by selling investments at a profit, by winning a large lottery prize, or by withdrawing money from your IRA or 401(k) (if you can do so without penalty).
- If you itemize deductions, reduce your deductions. For example, you could give less to charity.
- Claim fewer dependents.
- Don't claim other nonrefundable credits, such as the child care credit or education credits.
I'm not sure that this approach would really save you any money. It might just make you feel better because you see a larger solar credit on your tax return, but you could end up paying more tax in the end. In particular, eliminating one credit in order to claim more of another credit doesn't really accomplish anything.
