The credit amount equals $.01 per gallon for each percent of biodiesel included in the bioheat, not to exceed $.20 per gallon. To substantiate how the credit was computed, taxpayers should keep copies of all invoices or bills from the supplier(s) that include all the following:
- Date of purchase
- Number of gallons of bioheat purchased
- The percentage of biodiesel included in the bioheat
Note: The percentage of biodiesel included in the bioheat is the number or numbers preceded by the letter B in the bioheat designation. For example, bioheat designated B5 contains 5% biodiesel.
The credit is claimed for the tax year in which the bioheat is purchased.