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Southern Corridor GRIP 2017–2026 |
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7.1 Introduction
This chapter presents the capabilities and behaviour of the gas transmission system
in the Region, with reference to two factors:
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The security of supply in case of disruption of a supply route
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The change of flows pattern when the price of one of the available sources of
gas decreases
This investigation is done with the use of the ENTSOG network simulation model
(“NeMo”). This is a linear programming model which minimises the cost for meeting
the demand in all countries (or balancing zones). Each balancing zone is represent-
ed as a single node
1)
connected to neighbouring nodes with arcs having a limited
capacity equal to the sum of the capacities of existing interconnectors after applying
the “lesser of” rule. Each arc is divided into several parts with increasing cost
weights. This approach allows to utilise the arcs, more or less, evenly (otherwise
some of arcs would not be used at all while others would be fully used. Flow patterns
resulting from computation reflect this input condition. LNG and UGS capacities,
import points (from non-EU sources) and new projects are represented by additional
arcs.
The minimisation of the gas bill at EU level means that the results obtained may
differ from the optimal solution for each individual country.
The ENTSOG model calculations are based on
\\
Entry and Exit Capacities of IPs between two countries respectively balancing
zones as calculated by the relevant TSOs
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Working gas volume respectively injection/withdrawal capacities of UGS
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Send-out Capacities of LNG Regasification facilities
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National production capacities
This model was used to:
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Analyse the balance between demand and supply
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Estimate the resilience of the transmission network
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Estimate the flows between various countries and their sensitivity to supply
disruptions and level of prices.
\\
Estimate the impact of new projects to the mitigation of the consequences of
supply disruptions.
This is achieved through the examination of various scenarios modelled by modifying
the capacity assigned to different arcs. A more detailed description of the ENTSOG
Network Modelling tool can be found in the ENTSOG TYNDP 2017–2026
2)
.
It is important to keep in mind that this model only proposes one of many possible
combinations that cover the demand of various markets (one per country) while
respecting the constraints regarding:
\\
the capacity of interconnections and entry points (from third countries) and
\\
the availability of supply sources
1) There are a few countries in the EU where the internal transmission system applies constraints or competing capacities
in the gas transmission within the country. In such cases a country may be represented by more nodes
2) ENTSOG TYNDP 2017– 2026, Annex F – Methodology