Settlement Adjustment after Demand Control Events

A BSC rule change was implemented on 12 October 2020, requiring Elexon to determine whether Settlement Adjustment Processes (SAPs) should be used if a Demand Control Event (DCE) occurs in future.

The change is an example of how the BSC Panel and Elexon proactively work together, learning from key industry events to evolve the BSC so that it is more efficient.

The Demand Control Event in August 2019

On 9 August 2019 a power cut impacting more than one million consumers occurred following the combined loss of several larger and smaller generators.

DCEs such as this are rare as Britain has a resilient energy system. When one does occur it affects the Settlement position of BSC Parties, as it changes the volumes of electricity that might have otherwise been imported or exported, if there hadn’t been a major supply interruption.

The Settlement Adjustment Processes 

In 2015, BSC Modification P305 ‘Electricity Balancing Significant Code Review Developments’ introduced the SAPs if DCEs occur. This requires Elexon, certain BSC Parties, Party Agents and Agents to work together to estimate the amount of electricity that would have been used or exported by disconnected customers. The process then makes sure this is reflected in Trading Parties Imbalance volumes (and ultimately the Imbalance charges they pay).

Following the August 2019 DCE, the BSC Panel was concerned that the cost of running this process actually outweighed the benefit of adjusting Parties’ Imbalance charges. The Panel raised P397 to address this.

What Elexon would be required to do in future

If a DCE occurred in future, P397 ‘Assessing the benefits of adjusting Parties’ Imbalances following a Demand Control Event’ now requires Elexon to determine the nature of the DCE and whether the cost of carrying out the SAPs is outweighed by the benefit to Settlement.

Depending on the outcome of this calculation, Elexon would inform Licensed Distribution System Operators (LDSOs) National Grid ESO, certain Party Agents and BSC Agents whether the SAP should be completed or not.


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