15-32-202. Taxable years in which credit may be claimed -- carryover. The tax credit is to be deducted from the taxpayer's income tax liability for the taxable year in which the energy system was acquired by the taxpayer. If the amount of the tax credit exceeds the taxpayer's income tax liability for the taxable year, the amount which exceeds the tax liability may be carried over for deduction from the taxpayer's income tax liability in the next succeeding taxable year or years until the total amount of the tax credit has been deducted from tax liability. Notwithstanding the foregoing provision, no tax credit may be carried over for deduction after the fourth taxable year succeeding the taxable year in which the energy system was acquired.