Market Time Unit (MTU)
The Market Time Unit (MTU) is the smallest time bucket on which European electricity markets clear and settle — every bid, activation, price and imbalance is anchored to one MTU. Across the EU the MTU has been 15 minutes since 1 October 2025 (SDAC migration), reduced from one hour. Estonia's day-ahead, intraday, BBCM, MARI and PICASSO clearings all run on the 15-minute MTU; legacy hourly series remain in the BTD Archive.
The Market Time Unit (MTU) is the smallest time bucket on which European electricity markets clear and settle — every bid, activation, price and imbalance is anchored to one MTU. Across the EU the MTU has been 15 minutes since 1 October 2025, reduced from one hour, following the migration of the single day-ahead market (SDAC) to a 15-minute granularity mandated by Article 53 of the Electricity Balancing Guideline.
Why 15 minutes
Faster MTUs reduce the structural imbalance baked into the gap between scheduled-and-actual flows. With one-hour MTUs, the system carried 60 minutes of accumulated forecast error before any settlement reset; with 15-minute MTUs, errors clear four times more frequently and the value of fast-responding flexibility — batteries, aggregated demand response — increases proportionally. The change also aligns trading granularity with aFRR procurement and mFRR activation cycles, which were already 15-minute or shorter.
Where MTU shows up
MTU is the time index for: day-ahead clearing prices; intraday delivery slots; MARI and PICASSO activation auctions; BBCM capacity procurement results; the imbalance price; and the Direction of System Balancing indicator. The Baltic Transparency Dashboard publishes most reports at 15-minute resolution (PT15M) — the field "MTU" in those datasets is the 15-minute clock-aligned interval (00:00–00:15, 00:15–00:30, etc.) in local time.
Estonia and the Baltics
The three Baltic TSOs moved imbalance settlement to 15-minute MTU in 2025, ahead of the EU-wide SDAC cutover on 1 October 2025. The Baltic capacity-procurement market has cleared in 15-minute slices since its 4 February 2025 launch, and MARI / PICASSO clear at the same resolution. Older series in the BTD Archive still report at PT1H — these are the legacy hourly imbalance and activation data and should not be combined with current PT15M series without resampling.
Where you see this in Baltic data
Every dataset on the Baltic Transparency Dashboard carries an MTU-aligned timestamp; on Volton, the day-ahead spot price and the imbalance price both display 15-minute MTU resolution natively.
Sources
EBGL Article 53 (15-minute imbalance settlement) · ENTSO-E: Electricity Balancing · Nord Pool: 15-minute SDAC migration · Baltic Transparency Dashboard
Frequently asked
- What is a Market Time Unit?
- The MTU is the smallest time bucket on which European electricity markets clear, activate and settle. Day-ahead, intraday and balancing prices are all published for one MTU at a time. Since 1 October 2025 the EU-wide MTU is 15 minutes, replacing the previous one-hour standard.
- Why did Europe move to 15-minute MTU?
- Article 53 of the EU Electricity Balancing Guideline (Regulation 2017/2195) mandates 15-minute imbalance settlement to reduce the structural imbalance baked into longer trading periods. Faster settlement clears forecast errors more often and increases the value of fast-responding flexibility — batteries and demand response — proportionally.
- When did Estonia move to 15-minute MTU?
- The three Baltic TSOs moved imbalance settlement to 15-minute MTU during 2025, ahead of the EU-wide SDAC cutover on 1 October 2025. The Baltic balancing capacity market (BBCM) has cleared in 15-minute slices since its launch on 4 February 2025, and the MARI and PICASSO platforms have always operated at 15-minute granularity.
- Are old BTD time series in 15-minute MTU?
- No. Reports in the BTD Archive section are PT1H (one-hour) — the legacy hourly imbalance and activation data. Current reports (current_balancing_state and the live balancing dashboards) are PT15M. Combining them requires resampling; do not concatenate raw series across the cutover date.