40 CFR 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 by using Equation F-9 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 = Søderberg technology specific emission factor (1.7 metric tons CO2/metric ton Al produced).

MPs = Metal production from Søderberg process (metric tons Al).

(b) For other parameters, use the average of the two most recent data points after the missing data.