Bid Offer Data (BOD)

This group of pages contains functions to view bid offer data values. These include the five sets of offer and bid pairs (10 in total) with each pair containing a level and a bid and offer price to apply within the balancing mechanism. The balancing mechanism works such that after gate closure National Grid is able to adjust the output of units within the parameters set by units dynamic data. In doing so the unit will be paid based upon the prices submitted to National Grid and the levels of adjustment a unit is willing to make at those prices.

The Latest page allows the user to view on a web page the latest bid offer data.

The Download page allows the user to download a file containing bid offer data for a date range.

This summary information or data is indicative data only and is derived from balancing mechanism reporting service data (which is copyrighted by ELEXON Ltd who makes it available without warranty).

Worked Example: The following is an example of Bid Offer Data for a single singlement period for a single unit.

The above unit is saying that for any decreases in output up to 500MW the unit will pay £35/MWh to be released from the obligation to generate power with this action able to be cancelled by the unit receiving £48.90/MWh subsequent to having already been paid the £35/MWh. For instance the unit may have had an FPN of 400MW and might be asked to reduce output by 100MW. In this instance the unit might over a period of one hour have sold 400MW, delivered 300MW and effectively bought the 100MW shortfall at a discount price of £35 from National Grid.

In terms of generation increases the unit is willing to increase output initially by up to 185MW for £50/MWh, but would then require £56/MWh for up to 400MW of further increases. In this instance the unit might have sold 200MW and then effectively sold a further 200MW to National grid at £50/MWh for 185MW of that increase and at £56/MWh for the remaining 15MW of the increase, resulting in an overall delivery of 400MW.

Note that this bid offer data must be combined with both operational and dynamic data. For instance a unit with an MEL (availability) of 300MW and an FPN of 200MW is only capable of 100MW of power increases. While a unit with an FPN of 0MW cannot decrease output at all. Moreover if a reduction takes a unit below its SEL (Stable Export Limit) it must be turned off.