If a tax credit exceeds your tax liability, that additional amount can usually be carried forward to the succeeding taxable year. Example: you paid $28,800 for a PV solar panel system after CA Rebate. Your maximum tax credit amount is $8,640 or 30% of the system’s $20,160 net cost. If your tax liability is $5,000, you can claim a maximum of $5,000 on your 2009 taxes. The additional $3,640 tax credit can be claimed on the following year’s taxes.