P204 – Scaled Zonal Transmission Losses

Formal title: Scaled Zonal Transmission Losses

Current Status

Initial Written Assessment
Assessment Procedure
Report Phase
With Authority
Awaiting Implementation


Proposed Modification P204 seeks to introduce a zonal scheme for the allocation of the variable (heating) element of transmission losses, whereby zonal Transmission Loss Factors (TLFs) would be calculated for each BSC Year on an ex-ante (forecast) basis for each GSP Group (‘TLF Zone’) using a Load Flow Model based on the solution for P198. Under P198, some BM Units in some TLF Zones (e.g. Generators in GSP Groups in the south and Suppliers in GSP Groups in the north) would be credited with energy through the Transmission Loss Multiplier (TLM) as a result of the introduction of zonal TLFs, whilst the Metered Volumes of other BM Units would be scaled down (i.e. they would receive an energy debit to fund that credit). In contrast, P204 seeks to ensure that on average (as far as is practicable) no BM Units are credited with energy (i.e. receive payments), as a result of a zonal allocation of transmission losses, through the TLM. Under P198 a scaling factor of 0.5 is applied to the zonal TLFs. P204 proposes a different scaling factor calculated so that, on average, only energy debits due to losses would be sought, with no debit (or credit) sought for the most favourable locations. Furthermore, P204 proposes that both zonal TLFs and scaling factors are calculated and applied on a seasonal basis, by each BSC Season. No Alternative Modification has been developed for P204.


On 17 July 2008, the Authority published an open letter (see below) stating it was no longer in a position to reach a decision on the following Modification Proposals: P198 – Introduction of a Zonal Transmission Losses scheme P200 – Introduction of a Zonal Transmission Losses scheme with Transitional Scheme P203 – Introduction of a seasonal Zonal Transmission Losses scheme P204 – Scaled Zonal Transmission Losses. These Modification Proposals are therefore closed.


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