PGA is the purchased gas adjustment per unit.
S is the anticipated yearly gas commodity sales volume for each customer classification or grouping.
C is the volume of applicable commodity purchased for each customer classification or grouping required to meet sales, S, plus the expected lost and unaccounted for volumes.
Rc is the weighted average of applicable commodity prices or rates, including appropriate hedging tools costs, to be in effect September 1 corresponding to purchases C.
D is the total volume of applicable entitlement reservation purchases required to meet sales, S, for each customer classification or grouping.
Rd is the weighted average of applicable entitlement reservation charges to be in effect September 1 corresponding to purchases D.
Z is the total quantity of applicable storage service purchases required to meet sales, S, for each customer classification or grouping.
Rz is the weighted average of applicable storage service rates to be in effect September 1 corresponding to purchases Z.
Rb is the adjusted amount necessary to obtain the anticipated balance for the remaining PGA year calculated by taking the anticipated PGA balance divided by the forecasted volumes, including storage, for one or more months of the remaining PGA year.
E is the per unit overcollection or undercollection adjustment as calculated under subrule 19.10(7).
The components of the formula shall be determined as follows for each customer classification or grouping:
Unless a utility receives prior commission approval to use another methodology, a utility shall use the same weather normalization methodology used in prior approved PGA and rate case.
The annual filing shall restate each factor of the formula stated in subrule 19.10(1).
The annual filing shall be based on customer classifications and groupings previously approved by the commission unless new classifications or groupings are proposed.
The annual filing shall include all worksheets and detailed supporting data used to determine the purchased gas adjustment volumes and factors. The utility shall provide an explanation of the calculations of each factor. Information already on file with the commission may be incorporated by reference in the filing.
Periodic filings shall include all worksheets and detailed supporting data used to determine the amount of the adjustment.
Changes in factors S or C may not be made in periodic purchased gas filings. A change in factor D or Z may be made in periodic filings and will be deemed approved if it conforms to the annual purchased gas filing or if it conforms to the principles set out in 19.10(6).
The utility shall implement automatically all purchased gas adjustment changes which result from changes in Rc, Rd, or Rz with concurrent commission notification with adequate information to calculate and support the change. The purchased gas adjustment shall be calculated separately for each customer classification or grouping.
Unless otherwise ordered by the commission, a rate-regulated utility's purchased gas adjustment rate factors shall be adjusted as purchased gas costs change and shall recover from the customers only the actual costs of purchased gas and other currently incurred charges associated with the delivery, inventory, or reservation of natural gas. Such periodic changes shall become effective with usage on or after the date of change.
Negative differences in the reconciliation shall be considered overbilling by the utility, and positive differences shall be considered underbilling. This reconciliation shall be filed with all worksheets and detailed supporting data for each particular purchased gas adjustment clause. Penalty purchases shall only be includable where the utility clearly demonstrates a net savings.
The quotient, determined on the same basis as the utility's tariff rates, shall be added to the purchased gas adjustment for the prospective ten-month period beginning November 1.
The minimum amount to be refunded by check shall be $10. This adjustment shall be determined by dividing the overcollection by the anticipated sales volume for the prospective ten-month period beginning November 1 as determined in subrule 19.10(1) for the applicable purchased gas adjustment clause. The quotient, determined on the same basis as the utility's tariff rates, shall be a reduction to that particular purchased gas adjustment for the prospective ten-month period beginning November 1.
This rule is intended to implement Iowa Code section 476.6(11).
Iowa Admin. Code r. 199-19.10