27.—(1) Regulation 19 of the ESO Regulations is amended as follows.
(2) For paragraph (3) substitute—
“(3) The supplier's collateral requirement for a day (“the relevant day”) is determined by reference to the most recent period (“the relevant period”) of 21 consecutive days in respect of which the BSCCo had carried out a BSC volume allocation run prior to the last working day before the relevant day.”.
(3) For paragraph (4) substitute—
“(4) For each day in the relevant period, the amount of electricity supplied by the supplier on that day, less any amount of EII excluded electricity supplied by that supplier on that day, (both as determined on the last working day before the relevant day) multiplied by the interim levy rate which applies in relation to the relevant day gives a relevant amount.”.
(4) In paragraph (8)(b) for “BSC reconciliation run” substitute “ BSC volume allocation run ”.