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TAR NC Implementation Document – Second Edition September 2017 |
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Reserve Prices for Interruptible
Capacity Products
INTERRUPTIBLE DISCOUNTS
Responsibility: the level of discounts is subject to consultation per Article 28(1)
by NRA; subject to decision by NRA
General
Article 16 requires the calculation of reserve prices for standard interruptible capac-
ity products by applying a discount to the reserve prices for the corresponding
standard firm capacity products. Discounts can be
ex-ante
or
ex-post
:
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An ex-ante discount involves an upfront calculation based on the probability of
interruption and the estimated economic value of the product. An ex-ante
discount provides a reserve price for a standard interruptible capacity product.
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An ex-post discount compensates network users in the event of interruption.
Ex-post discounts can only apply to IPs where physical congestion did not
prompt any interruption of capacity in the preceding gas year. The application
of an ex-post discount replaces an ex-ante discount to the reserve price for a
standard interruptible capacity product. With an ex-post discount, the reserve
price for interruptible product should be the same as the reserve price for a firm
product of an equivalent duration.
As of March 2017, the majority of the EU TSOs offer ex-ante discount. Ex-post
discounts are offered in Austria, the Czech Republic, Hungary, Poland, Romania
and Slovakia.
It is not possible to combine ex-ante and ex-post discounts for the same interrupti-
ble product at the same IP. The formulas for calculating ex-ante and ex-post dis-
counts are set out below.
The level of the ex-ante and ex-post discounts is subject to NRA approval in accord-
ance with the process outlined in Article 28.
Ex-ante approach – how to calculate discounts
The TAR NC sets the ex-ante discount for standard interruptible capacity products
proportional to the probability of interruption ‘Pro’ and the adjustment factor ‘A’,
calculated in accordance with the following formula:
Di
ex-ante
= Pro × A × 100%
Where:
Di
ex-ante
is the level of an ex-ante discount;
Pro
factor is the probability of interruption which refers to the type of standard
interruptible capacity product;
A
is the adjustment factor applied to reflect the estimated economic value of the
type of standard interruptible capacity product, calculated for each, some or all IPs,
which shall be no less than 1.
ARTICLE 16