Q699. How do I determine the quantity of CO2 emissions produced for hydrogen production process units that use multiple fuels and feedstocks?

A699. For units not monitored by a CEMS, the CO2 emissions should be the sum of the annual emissions associated with each fuel and feedstock used for hydrogen production, using the applicable equations in paragraphs 98.163(b)(1) through 98.163(b)(3).  For example, if your hydrogen production process unit uses refinery fuel gas for fuel and natural gas for feedstock, Equation P-1 should be applied separately for each fuel/feedstock to calculate the CO2 emissions from each.  These CO2 emissions should then be summed and the total reported. For CEMS-monitored units, the CO2 emissions should be determined using the Tier 4 calculation methodology as described in 98.163(a).