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Central Eastern Europe GRIP 2017
4.3.1.1 Winter period
From each country, entry capacities at each interconnection point, as well as the
withdrawal capacity of storage facilities, national production, domestic demand, and
exit capacities to neighbouring countries are used for the calculation of regional N-1.
After a matching/correction of entry and exit capacities of each interconnection point
(lesser-of rule), the surplus gas is allocated to neighbouring countries to meet the
domestic demand of countries which are “in need”. The N-1 value for winter is
calculated for each country by setting the interconnection points of the main supply
corridor to zero or to a minimum volume that an upstream country (next or nearer
to Ukraine/Belarus transport to a relevant interconnection point) is able to export. If
the investigated country has surplus gas after satisfying its demand for sharing, the
gas is then allocated to downstream countries, where necessary. These values are
used for the N-1 calculation as entries for a particular country. In case the N-1 value
is equal to or above 1, this means that the respective country is able to cover its own
demand in case of a gas supply disruption via Ukraine or Belarus. Under the
assumption that underground storage facilities are filled up during the summer
period (as the N-1 calculation assesses the infrastructure, not the supply standard),
the maximum deliverability has been applied. The stock levels of underground
storage facilities, as well as the duration of the disruption, have not been taken into
consideration in the winter formula.
The N-1 Formula for the winter period is based on REG 994/2010, when the
technical capacity of the single largest gas infrastructure in the original formula is
replaced by all interconnections with Ukraine (or Belarus respectively) in the
modified formula for the CEE GRIP.
Winter N-1 Formula:
Where:
EP_IN
All border entry points (transmission and LNG) capable of supplying gas
to the calculated area (GWh/d)
P
National production, entry capacity (GWh/d)
S
Storage, entry capacity (withdrawal) (GWh/d)
D_MAX
Domestic winter peak demand (1 in 20) (GWh/d)