Q81. If a combustion unit is greater than 250 mmBtu per hour, combusts a biomass fuel listed in Table C-1, and receives HHV data at the required frequency in §98.34(a), may Tier 1 be used per 40 CFR 98.33(b)(1)(iii)?

A81. No. For a unit of any size that combusts biomass, if HHV is sampled at the minimum frequency required for Tier 2 as part of routine operations, Tier 1 may not be used for determining the CO2 emissions from the combustion of biomass.  Tier 2 must be used instead. (See §§98.33(b)(1)(iv), and 98.34(a))