Frequency response services
Energy throughput is estimated by modelling the contracted response for each service using the physical (measured) grid frequency provided by National Grid ESO. Because grid frequency data for a given month is actually published a few days after the end of the month, and therefore after the publication of the Modo Leaderboard, we apply the corresponding month's figures from the previous year. This is done for both BMU and non-BMU registered assets.
For Balancing Mechanism-registered assets (BMUs), energy throughput is calculated by using an integral function on physical reported volumes submitted to ELEXON. Any volume dispatched in the Balancing Mechanism through Bid-Offer-Acceptances is also added on top of this.
We estimate energy throughput for non-BMUs by taking their highest contracted capacity in frequency response markets from the previous five days and multiplying by the asset's duration. We then assign this to those settlement periods in which we believe assets are pursuing merchant activity.