74.28—Allowance allocation for combustion sources becoming opt-in sources on a date other than January 1.
        
        (a) Dates of entry.
        
        (1) 
         If an opt-in source provided monthly data under  § 74.20, the opt-in source's opt-in permit may become effective at the beginning of a calendar quarter as of January 1, April 1, July 1, or October 1.
    
    
        
        (2) 
         If an opt-in source provided annual data under  § 74.20, the opt-in source's opt-in permit must become effective on January 1.
    
    
        
        (b) Prorating by Calendar Quarter.
         Where a combustion source's opt-in permit becomes effective on April 1, July 1, or October 1 of a given year, the Administrator will prorate the allowance allocation for that first year by the calendar quarters remaining in the year as follows:
 
    
    Allowances for the first year
    
    
    
    
        
        (i) 
         “Remaining calendar quarters” shall be the calendar quarters in the first year for which the opt-in permit will be effective.
    
    
    where unit conversion
        = 2 for coal
        = 0.001 for oil
        = 1 for gas
        For other fuels, the combustion source must specify unit conversion;
        and where starting month
        = April, if effective date is April 1;
        = July, if effective date is July 1; and
        = October, if effective date is October 1.