P198 – Introduction of a Zonal Transmission Losses scheme

Formal title: Introduction of a Zonal Transmission Losses scheme

Current Status

Initial Written Assessment
Assessment Procedure
Report Phase
With Authority
Awaiting Implementation


Proposed Modification P198 seeks to allocate the ‘variable’ (heating) element of transmission losses to BSC Parties on a ‘zonal’ locational basis, according to the extent to which each Party is estimated to give rise to such losses. The solution for Proposed Modification P198 is based closely on previous Modification Proposal P82. It involves the calculation of one Adjusted Annual Zonal Transmission Loss Factor (TLF) value per TLF Zone for each BSC Year, with no phased implementation. TLF Zones would be based on Grid Supply Point Groups, and the TLFs would be calculated on an annual ex-ante (forecast) basis for each forthcoming BSC Year (1 April – 31 March). All BM Units within a Zone would receive the Adjusted Annual Zonal TLF value for that Zone in every Settlement Period of the applicable BSC Year. Alternative Modification P198 is the same as the Proposed Modification, except that it comprises: · An annual ex-ante calculation of four Adjusted Seasonal Zonal TLF values for each TLF Zone, one for each BSC Season; and · A linear phased implementation of these Adjusted Seasonal Zonal TLF values over the first four BSC Years of the scheme, such that TLFs would be applied at 20% of their full value in BSC Year 1, 40% in BSC Year 2, 60% in BSC Year 3, 80% in BSC Year 4, and 100% in BSC Year 5 and all subsequent years.


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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