# 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, CO<sub>2</sub> emissions can be estimated from aluminum production by using Equation F-9 of this section.
Where:
ECO<sub>2</sub> = CO<sub>2</sub> emissions from anode and/or paste consumption, metric tons CO<sub>2</sub>.
EF<sub>p</sub> = Prebake technology specific emission factor (1.6 metric tons CO<sub>2</sub>/metric ton aluminum produced).
MP<sub>p</sub> = Metal production from prebake process (metric tons Al).
EF<sub>s</sub> = Søderberg technology specific emission factor (1.7 metric tons CO<sub>2</sub>/metric ton Al produced).
MP<sub>s</sub> = 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.
[74 FR 56374, Oct. 30, 2009, as amended at 75 FR 79156, Dec. 17, 2010; 81 FR 89253, Dec. 9, 2016]