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Glossary · Energy industry & energy transition

Schedule (Fahrplan)

schedule Balancing group electricity market Day-ahead market Intraday market Balancing energy forecast

In the electricity market, a schedule (Fahrplan) is the time-resolved statement of how much electric power is exchanged between balancing groups, or fed in or withdrawn at an injection or withdrawal point, in each time interval. This is how the German Electricity Grid Access Ordinance (StromNZV) defined the term until the end of 2025. Schedules assign deliveries to a balancing group, a trading partner or a control area. In the German and European markets, the quarter-hour is the standard grid: for each quarter-hour, an average power in megawatts is stated. Over the duration of the interval, this yields an amount of energy in megawatt-hours.

The schedule translates commercial agreements into a time structure that can be used in operations. A supplier, a power plant operator or a trader cannot simply buy or sell electricity "sometime tomorrow". The delivery must be allocated to specific quarter-hours. In this way, the schedule links the electricity market, balancing group management and grid operation.

Distinction: forecast, physical flow, dispatch schedule

A schedule is not a mere forecast. A forecast states what is expected to happen, for example how much wind power will be fed in or how much a customer portfolio will consume. The schedule is the binding notification. It may be based on forecasts, but it becomes binding through trades and the rules of the balancing group contract: the transmission system operator uses schedules notified in due time as the basis for balancing.

A schedule also does not describe the actual physical flow of electricity. If a trader sells electricity from northern Germany to southern Germany, the electricity still follows the physical properties of the grid and not the contract. The schedule only allocates quantities for balancing purposes, that is, who is responsible for which delivery and when. Nor is it to be equated with a power plant dispatch schedule. The dispatch schedule determines which plant technically runs when. A trader, by contrast, can buy and sell positions without owning any plants, and a portfolio of many plants can be managed jointly. The schedule is the balancing-related external face of these decisions.

Power and energy quantity

A schedule works with power over time. If a delivery of 40 megawatts is notified for a quarter-hour, this corresponds to 40 MW × 0.25 h = 10 megawatt-hours. A schedule value of 100 MW therefore does not mean that "100 megawatts are consumed". It sets an average power for a particular time grid. The energy quantity results only when this power is multiplied by the duration. With fluctuating wind and solar feed-in, with battery storage and with flexible loads, this time resolution becomes the core of portfolio management.

Load profiles are not schedules either. For small customers without load profile metering, the grid operator in Germany allocates consumption to the supplier's balancing group by means of standard load profiles. The supplier procures the corresponding quantities through trades, which it notifies as schedules. The load profile is thus a planning basis, and the schedule reflects the supply transactions with which the supplier covers the expected demand.

How schedules are notified

In Germany, the balancing group responsible party notifies its schedules to the competent transmission system operator. The Bundesnetzagentur's standard balancing group contract requires complete schedules with a balanced power balance in every quarter-hour. A separate schedule must be submitted for each day, at most one month in advance. Schedules between two balancing groups must match each other as mirror images: if one side notifies a delivery, the counterparty must notify the same quantity for the same quarter-hour as a withdrawal. If the notifications differ, the matter is resolved according to the contractual rules. For schedules within Germany, the smaller value is then applied for the quarter-hour concerned (minimum rule). The schedule thus also serves to check whether trading relationships are free of contradiction.

Many positions for the following day arise in the day-ahead market. The coupled European day-ahead auction takes place at 12:00 CET. Since the delivery day of 1 October 2025, it has been conducted in all participating bidding zones in quarter-hour products instead of hourly products; Ireland remains at 30 minutes. Quarter-hour products are also available in all bidding zones in the Europe-wide coupled intraday market. The closer the time of delivery, the more accurate the wind, solar and consumption forecasts become. Intraday trading allows this new information to be turned into amended schedules.

Until the end of 2025, the StromNZV provided as follows: day-ahead schedules had to be notified by 14:30, unless otherwise permitted or determined. Schedule changes within a control area and between control areas were possible for every quarter-hour with a lead time of at least one quarter-hour. Schedules within a control area could be changed retroactively until 16:00 on the following working day. In the event of unplanned power plant outages, the transmission system operator balanced the imbalance for four quarter-hours, after which the balancing group responsible party was itself responsible. The transmission system operator could reject changes to cross-control-area schedules if they would have caused a congestion.

On the legal status: the StromNZV expired at the end of 31 December 2025. The Bundesnetzagentur transferred its contents into determinations (Festlegungen) on the basis of Section 20(3) EnWG, for example into the GPKE determination and the standard balancing group contract. By its own account, the authority initially adopted the established rules largely verbatim. The deadlines mentioned above therefore describe the previous system. Which values apply in an individual case is now determined by the respective valid determinations and contract annexes.

Deviations and balancing energy

No schedule fully reflects reality. The wind blows differently than forecast, photovoltaics deliver less when it is cloudy, power plants fail, consumers behave differently. More precisely, a balancing group deviation does not arise from comparing a single schedule with the measurement. It is the balance of all feed-ins and withdrawals of a balancing group in a quarter-hour: measured quantities or quantities allocated by profile, as well as all schedule deliveries and withdrawals. The balancing group responsible party bears the economic responsibility for this balance. It is settled via balancing energy.

Balancing energy is not an arbitrary penalty. It is intended to encourage careful management of the balancing group. Anyone who plans systematically wrongly shifts risks onto the overall system. The balancing energy price is intended to allocate costs according to the polluter-pays principle. How strongly it takes effect depends on the pricing rules and on the direction of the system deviation. If many balancing groups deviate in the same direction, the transmission system operator must deploy more control reserve. Control reserve stabilises the frequency in real time. Schedules start earlier and are meant to organise the expected state so well that as little short-term balancing as possible is needed.

Significance in the power system

The schedule shows that electricity markets are tied to time. A kilowatt-hour on Monday morning is, in system terms, a different commodity from a kilowatt-hour at night. With a rising share of wind and photovoltaics, this gains weight. Direct marketers must continuously update their forecasts and adjust their schedules. Forecast errors affect balancing groups, intraday prices and the need for balancing energy. According to EPEX SPOT, the quarter-hour grid is intended to help integrate renewable generation better, because it changes within an hour.

Storage and flexible consumers also depend on schedules. A battery can charge when electricity is cheap and discharge when it is scarce. Heat pumps, electrolysers or industrial processes can be shifted in time under certain conditions. This flexibility becomes effective in the market only when it is represented precisely in time in positions and schedules.

Finally, the schedule touches the boundary between market and grid. Within a bidding zone, market participants can trade without reflecting every grid congestion in their schedule. If market results lead to congestion, grid operators intervene with redispatch. The schedule describes the commercial and balancing-related order, not automatically an operation that is technically feasible in the grid at every location.

Typical oversimplifications

  • "Schedules are bureaucracy": In fact, they coordinate many decentralised decisions. Without schedules, the costs of uncertainty would not disappear. They would arise in control reserve, balancing energy, redispatch or reserves.

  • "A schedule guarantees physical delivery": The market works on a balancing basis. A supplier can supply its customers through purchases without operating power plants. Physical stability is ensured by grid operation and system services.

  • "Schedule equals forecast": The forecast is an expectation. The notified schedule is the quantity that enters balancing.

Electricity supply can be understood neither through generation capacity alone nor through energy quantities alone. It requires an allocation of responsibility that is accurate to the quarter-hour. Schedules create this allocation. Deviations, costs and responsibilities can be measured against them.

Sources

Related glossary entries

Edited by eCMS on 11.11.2026 19:47

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