On the 3rd of October 2012, the Single Electricity Market (SEM) Committee published a proposed decision on the treatment of curtailment in tie-break situations (SEM-12-090). Two other documents were published alongside SEM-12-090. They were a Transmission System Operator (TSO) report examining the effect of three options outlined in SEM-12-028 on Dispatch Balancing Costs and wind curtailment and a TSO annex setting out the proposed methodology for distinguishing between events of constraints and curtailment.
The extended deadline for receipt of responses to these publications is close of business Monday the 19th of November 2012.
Summary of Proposed Decision
The Proposed Decision of the SEM-12-090 document is Pro-rata dispatch with defined curtailment limit.
This option involves the pro-rata treatment for curtailment of all operational windfarms in dispatch and the imposition of a cap / threshold for the payment of Dispatch Balancing Costs (DBC) compensation for curtailment. It is the SEM Committee’s intention that by 2020, there would no longer be DBC compensation available for curtailment of wind.
The features of this option are as follows:
On the dispatch side curtailment for all operational windfarms will be treated on a pro-rata basis, i.e. all operational windfarms (firm and non-firm) will be turned down on an equal basis by the TSO in a curtailment situation. On the market side, as per current rules, firm projects will be paid market revenues through DBC when curtailed. However this full compensation of curtailment for firm and partially firm generators (0.1% to 99.9%) will only continue up to a fixed point – at the absolute latest this will be the 1 January 2016.