How a settled imbalance price is decomposed
The published imbalance prices on a delivery day, and the components behind them. Every number here is served by the system operator; the only arithmetic performed is one subtraction, and it is shown on the page so it can be checked.
On this page
The decomposition
A settled imbalance price is not a single published quantity. It is a marginal price plus a penalty component, and the view separates them.
- Base price
- The marginal price of whichever direction actually answered in that quarter-hour. Where no direction was called, there is none.
- Alpha
- The penalty component the operator applied, signed by whether the system was short or long. It is what moves the settlement away from what the offers alone would have set.
- Published
- The settled imbalance price as the operator published it.
- Residual
- Published minus the parts. It is ZERO wherever the arithmetic on this page is the arithmetic the publisher used, and the column exists so you can see that rather than take it on trust. A non-zero residual past the tolerance is flagged.
Minute by minute, and quarter by quarter
Two resolutions, deliberately not averaged into one. System imbalance is the position the whole zone was in and ACE is the area control error the operator was steering against; negative is short. Both are read at the resolution the operator publishes them at rather than averaged up to the settlement period, because the shape within a quarter-hour is what explains the price it settled at.
The price chart comes first, followed by alpha and residual exceptions and then the minute-by-minute system chart. A missing per-minute read degrades that chart alone: quarter-hour prices come from a separate feed. An empty response is unconfirmed coverage, not evidence that nothing was published. A selected UTC quarter-hour stays marked when you move between merit order, settlement and the price comparison.
How settled the day is
A quarter-hour is restated as it validates, and only the latest version is served. Nothing here holds a copy, so a figure read today can differ from the same figure read tomorrow, and the view reports how many periods are validated, awaiting validation, or flagged by the publisher as a data issue. These counts appear beside the controls, together with the number of quarter-hours returned against the actual delivery day.
The folded quarter-hour ledger includes every delivery period, including periods without alpha and missing periods marked N/A. Published prices remain visible even when a base price is unavailable, so a missing decomposition input does not erase a price. The separate minute ledger contains every returned system-imbalance and ACE reading. Both export as CSV with UTC timestamps and the read time. UTC distinguishes the two occurrences of the repeated autumn hour. Period links open the matching quarter-hour's merit order.
What this view cannot say
Who was on either side of an imbalance. Settlement is published for the system, not per participant. A price is not a total cost: this view carries neither positions nor participant settlement figures. Nothing on this view is screened or thresholded either: it is a replay, not a detector.