How are the System Sell Price and the System Buy Price calculated?

For each half hour trading period or ‘Settlement Period’, the ‘cash-out prices’ or ‘energy imbalance prices’ (System Sell Price and System Buy Price) will be calculated based on the cost incurred by National Grid – the System Operator – to bring the system into balance (based on accepted Balancing Mechanism Bids and Offers). The System Buy Price (SBP) is applied to BSC Parties that have negative imbalances and the System Sell Price (SSP) to those that have positive imbalances.

More information about how the prices are calculated and applied can be found in the Imbalance Pricing Guidance