Today and Tomorrow Electricity Prices

WattSmart shows electricity prices for today and tomorrow using official day-ahead market results published via the ENTSO-E Transparency Platform. Day-ahead prices are published per bidding zone and per market time unit (hourly or, in most areas, 15-minute intervals), so you can plan energy use ahead of time.

What “today” and “tomorrow” prices actually mean

Day-ahead prices are the wholesale market prices determined after the day-ahead auction clears (market coupling), and they are published for each time interval of the delivery day (today) and the next day (tomorrow). ENTSO-E’s transparency rules specify that day-ahead prices for each bidding zone must be published no later than one hour after gate closure (for implicit allocation, “gate closure” is effectively tied to the market matching algorithm output time).

In practice, this means:

  • “Today” = the set of prices for the current delivery day (already known since the previous day’s auction).
  • “Tomorrow” = the next delivery day’s prices, published once day-ahead results become available.

When ENTSO-E day-ahead prices are published (and why timing can vary)

Most European day-ahead markets are coupled through Single Day-Ahead Coupling (SDAC), which produces one coherent set of results across many regions. Under normal conditions, coupled day-ahead results are typically published around late morning / midday Central European time. For example, market-coupling process documentation commonly references

preliminary results around 12:45 CET and final results around 12:57 CET, with the note that publication can differ slightly between market operators.

On some days, publication can be delayed (e.g., technical issues, partial decoupling). SDAC fallback documentation highlights that results may be delayed and still be published by the full decoupling deadline (e.g., up to 14:20) in severe delay scenarios.

When WattSmart starts showing “tomorrow” prices

WattSmart begins displaying tomorrow’s prices after ~11:00 UTC, because that’s when day-ahead results are available for most bidding zones on typical days.

  • If tomorrow’s prices are not published yet, you’ll still see today’s prices until the new data arrives.
  • If publication is delayed for your market, tomorrow prices may appear later than usual (the app updates automatically when the official data becomes available).

How the Today & Tomorrow view works in the app

WattSmart presents the same day-ahead data consistently across the UI:

  • Price chart: quickly spot low/high periods across today and tomorrow
  • Price table: exact values by time interval (hourly or 15-minute)
  • Home screen widgets: your at-a-glance view follows the same settings and updates with the same official data

Because the source is day-ahead market data, it’s ideal for planning:

  • shifting energy-intensive tasks to cheaper periods,
  • avoiding the most expensive intervals,
  • understanding how tomorrow compares to today at a glance.

Notes about time zones and intervals

Day-ahead data is published per bidding zone and market time unit. Depending on the market, prices can be hourly or 15-minute, and the “day” is shown according to the market’s delivery calendar (with DST changes handled by the underlying market time definitions).