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TAR NC Implementation Document – Second Edition September 2017 |
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Entry points are in rows, exit points are in columns.
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Distance between two points may theoretically vary depending on the flow
scenario
in case 2 points are connected via at least one unidirectional pipeline
1)
.
For example, in the current configuration the shortest path for gas between
storage point ‘A’ and bidirectional IP ‘K’ is simply along bidirectional pipeline
AK, and distance between A and K is therefore 10km. However, in a modified
configuration where pipeline AK would only allow flows from A to K (not any-
more between K and A), it would be still possible to flow gas at entry point K to
inject gas in storage A but along the pipeline via consumption point O. Further
to feedback received from stakeholders, ENTSOG would like to underline that
the shortest distance to flow gas between K and A would be the sum of distanc-
es KO and OA, and that this distance would be necessarily the one to use for
CWD distance calculation as per Article 8(1)(c), even if alternative longer routes
also exist to allow a flow scenario between K and A (e. g. KO, then OT, then TA).
Distance for flow scenario AK would still be 10 km, but distance for flow scenar-
io KA would be the sum of distances for KO and OA, that is 15.3km, compared
to 10km in the bidirectional case.
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If an entry point and an exit point are not connected according to a flow
scenario
, the distance between them in both directions is indicated by a ‘
0
’
written in red in the previous table. For example, storage point A and storage
point C are not connected according to a flow scenario: it is impossible to flow
gas within the network of the TSO from A to C or from C to A because of
unidirectional pipelines (section H to C is the problem in the ‘A to C’ direction,
section C to E is the problem in the ‘C to A’ direction).
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Flows from/to the same point are not considered as valid flow scenarios, and
are also marked with a ‘
0
’ in red (e. g. impossible to flow gas from A to A).
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Points S and T do not appear in the table since they are not relevant in tariff
derivation for the CWD counterfactual (neither entry, nor exit points).
1) Note that in Article 8 of TAR NC, the calculation of the average distance for an entry point AD
En
and the calculation for
an exit point ADE
X
both refer to the same distance D
En,Ex
. For flow scenario reasons, Article 8 should actually make a
distinction between D
A,B
and D
B,A
.
Original case: distance for flow scenario is the same for AK
and KA
Variant: distance for flow scenario is now longer for KA
because pipeline AK is now unidirectional
Figure 63:
Impact of flow scenarios on calculated distances
N
A
√13
√80
√137
√32
10
O
J
K
M
23/3
G
S
T
N
A
√13
√80
√137
√32
10
O
J
K
M
23/3
G
S
T