98.65—Procedures for estimating missing data.
A complete record of all measured parameters used in the GHG emissions calculations is required. Therefore, whenever a quality-assured value of a required parameter is unavailable (e.g., if a meter malfunctions during unit operation or if a required sample measurement is not taken), a substitute data value for the missing parameter shall be used in the calculations, according to the following requirements:
(a)
Where anode or paste consumption data are missing, CO2 emissions can be estimated from aluminum production per Equation F-8 of this section.
Where:
ECO2 = CO2 emissions from anode and/or paste consumption, metric tons CO2.
EFp = Prebake technology specific emission factor (1.6 metric tons CO2/metric ton aluminum produced).
MPp = Metal production from prebake process (metric tons Al).
EFs = Sderberg technology specific emission factor (1.7 metric tons CO2/metric ton Al produced).
MPs = Metal production from Sderberg process (metric tons Al).
(b)
For other parameters, use the average of the two most recent data points after the missing data.