ENTSOG Tariff NC - Implementation Document 2nd Edition

Ex-ante approach – how to calculate reserve prices When an ex-ante discount applies, the reserve prices of standard interruptible capacity products are calculated by applying the difference between 100% and the ex-ante discount to the reserve price of the equivalent standard firm capacity product. Although not explicitly stated by the TAR NC, the following formulas apply to calcu- late the reserve price of a standard interruptible capacity product: For yearly standard interruptible capacity product:

P int

= (1 – Di ex–ante

) × T

Where: P INT

is the reserve price for yearly standard interruptible capacity product;

Di ex-ante

is the ex-ante discount of the product;

T

is the reserve price for yearly firm capacity product.

For daily, monthly and quarterly standard interruptible capacity product:

P int

= (1 – Di ex–ante

) × ((M × S × T / 365) × D

Where: P INT

is the reserve price for daily, monthly or quarterly standard interruptible capacity product;

Di ex-ante

is the ex-ante discount of the product;

M

is the level of the multiplier corresponding to the respective standard capacity prod- uct; is the level of seasonal factor corresponding to the respective standard capacity product, if any;

S

T

is the reserve price for yearly firm capacity product;

D is the duration of the respective standard capacity product expressed in gas days. For leap years, the formula shall be adjusted so that the figure 365 is substituted with the figure 366.

For within-day standard interruptible capacity product:

P int

= (1 – Di ex–ante

) × ((M × S × T / 8760) × H

Where: P INT

is the reserve price for within-day standard interruptible capacity product;

Di ex-ante

is the ex-ante discount of the product;

M

is the level of the corresponding multiplier;

S

is the level of the corresponding seasonal factor, if any;

T

is the reserve price for yearly firm capacity product;

H is the duration of the within-day standard capacity product expressed in hours. For leap years, the formula shall be adjusted so that the figure 8760 is substituted with the figure 8784.

Please see Annex N for an example of a calculation of the reserve price for a monthly standard interruptible capacity product.

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