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Method note · measured

Monthly price swings by zone

What it measures

How much the day-ahead price swings inside a month: the median daily spread and hours below zero since the first year, and the hourly scatter lately.

Inputs

  • The daily spread (TB1, the day's dearest hour minus its cheapest) and the hours below zero per day for each of the six bidding zones, from the frozen yearly history and the rolling daily artefact
  • The day-ahead price on the canonical hourly grid for each zone over the rolling window, when the hourly cache is present at build time
  • The marginal-fuel model's monthly rows for the German overlay: the modelled running cost of a gas-fired plant and the monthly mean price

Method and weighting

Two windows are read separately and never mixed. From the daily record since the first year stated on the view: for each market-local calendar month, the median of the month's daily spreads, so that one extreme day cannot set the month, and the sum of the month's hours priced below zero. From the hourly record over the rolling window: the standard deviation of the hourly price around its monthly mean, the count of hours below the low threshold stated on the view, the near-zero hours solar and wind create, and the count above the high threshold, the scarcity hours. A month short of the minimum days or hours stated on the view is a gap.

No composite index is built. Two or three plain measures per month, each stated with its window, are what the view shows, because a built index invites the objection that it was built to fit.

The German overlay is the marginal-fuel model's monthly running cost of a gas-fired plant drawn beside the monthly mean price; it is an estimate, and the Marginal Fuel note explains it.

The readings under the charts carry one figure per position, filled from the same data for the zone chosen, and settle nothing.

Window

The daily measures run from the first year stated on the view to the last complete day, refreshed on the 1st and 15th of each month with the frozen years untouched; the hourly measures cover the rolling 12 months to the last complete day. The current window runs from to . Data last refreshed on .

Known limits

  • The hourly grid averages a quarter-hour market onto the hour, so the spread and the scatter it reports understate the finer-grained market.
  • The hourly measures exist only for the rolling window, so the gas-crisis months carry the daily measures alone; the view says which window each chart reads.
  • The frozen years are counted once and never revised; a later upstream revision reaches only the rolling window.
  • The gas overlay is a model, and it covers Germany only.

Used on

Sources: ENTSO-E, World Bank, European Central Bank. Each is described on the Data sources page.