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TAR NC Implementation Document – Second Edition September 2017
DISTANCE CALCULATION
Responsibility: subject to consultation per Article 26(1) by TSO/NRA, as NRA
decides; subject to decision by NRA
Shortest pipeline distance for capacity weighted distance
reference price methodology
To measure distance for the CWD, Article 8 considers the pipeline approach, which
selects the shortest distance of the pipeline routes between: (1) an entry point or a
cluster of entry points; and (2) an exit point or a cluster of exit points.
Clustering introduces two possibilities:
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‘Distance before cluster’: calculate the weighted average of the shortest pipe-
line distances of all physical points of the cluster. The weights can depend on
the technical capacity.
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‘Cluster before distance’: select a focal point of the cluster, and then calculate
the shortest distance of the pipeline routes from or to such a focal point. A dom-
inant physical point of the cluster can constitute the focal point.
When applying CWD, Article 8 does not consider other distance methodologies such
as: (1) average pipeline distance, as opposed to the shortest; and (2) airline distance.
However, a TSO/NRA can consider such methodologies within a proposed alter
native RPM, including a Modified CWD. Below are two examples of alternative
approaches to distance.
In addition, the concept of distance is closely linked to the one of ‘flow scenario’ in
Article 8 for CWD. The definition of a flow scenario is provided in Article 3 of the TAR
NC and it is illustrated in Annex E. In simplified terms, an entry point and an exit
point may be combined in a flow scenario if there is at least a pipeline to connect
them. As regards cases which do not constitute a flow scenario, ENTSOG believes
that:
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If there exists no pipeline to connect a specific entry point and a specific exit
point in a given network, these two points cannot be combined into a flow
scenario.
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If a network point is both an entry and an exit point, the entry followed by the
exit at this point does not constitute a flow scenario. Such use of TSO networks
is very insignificant in most networks, and considering it as a flow scenario
would distort relative distances and tariffs calculated for CWD compared to
combinations of distinct entry and exit points.
As developed in Annex E, these two cases do not correspond to flow scenarios and
where applicable it is necessary to correct both distances and forecasted contracted
capacities to avoid tariff distortions.
ARTICLE 8(1)(C)