Beginn of reporting

The begin of reporting refers to the date at which the respective reporting company begins to report data for a unit for which reporting is required. The reason for the beginning of reporting can either be the start of trial operation of a new unit, the launch of commercial operation or the beginning of operation by a new owner.

Bidding Zone

A bidding zone is the largest geographical area within which market participants are able to exchange energy without capacity allocation. Currently, bidding zones in Europe are mostly defined by national borders. However, the existing European electricity target model requires defining bidding zones based on network congestions. Hence, alternative bidding zone configurations based on this principle need to be examined.

List of bidding zones:



TenneT (DE)










National Grid










TenneT (NL)





EirGrid plc








Svenska kraftnät
















Bottleneck output

The bottleneck output of a unit corresponds to the continuous output which can be achieved under normal conditions. It is limited by the part of the plant which has the lowest efficiency (bottleneck). Parts of the plant which cannot be used for a short period do not reduce the bottleneck output.

Cold reserve

Cold reserve refers to a generating unit which has been decommissioned but has a valid operating permit and can be used to the full extent from a technical perspective and, which is, however, not operated for other reasons (e.g. long-term fuel shortage, too high fuel prices, too low exchange prices). Recommissioning requires the preservation measures to be removed and is, hence, not possible right away. For this reason, the output which is part of the preserved cold reserve is not directly usable for the market either.

Commissioning phase

Units are not available for commercial purposes during the commissioning stage since the suitability of the respective units for continuous operation needs to be proven prior to the commercial use. These suitability tests correspond to technical and official tests. The output during the commissioning stage is fed into or taken from the public power grid as unsecured output. Reliable ex-ante data on this is not available

Continuous output

The continuous output of a unit is the maximum output which is provided during proper operation of the unit without restrictions in terms of time and does not affect the unit's service life (operating time) and safety.

Control area

From the perspective of operations in the field of electricity supply, the control area is the grid area which the responsible transmission system operator controls, regulates and monitors. The output imbalances in the balancing zone (differences between planned target and actual values of the exchange of output with other balancing zones) are compensated by the transmission system operator through the activation of balancing power which is put out to tender.

Data coverage

The data coverage indicates the total installed capacity for all units which are reported on the transparency platform and in operation for a country and specific stage of the value chain. It is differentiated between the following stages of the value chain: production, storage, transmission and consumption for the commodities power and natural gas.


Permanent and final shut-down of a unit on account of the expiry or surrender of the official operating permit.

End of reporting

The end of reporting is characterised by the complete shut-down of a unit for which reports have been submitted so far, by the transfer of the reporting requirement to another reporting company as a result of a sale or the termination of the provision of data regarding this unit for contractual reasons.


Ex-ante values are forecast values which are used for planning the management of actual operations.


Ex-post values are actual values from the operations which can be published and, if required, specified in more detail afterwards. In this context both measured and counter values can be used. If measured values are used, these are replaced by counter values from calibrated counters as soon as such data become available.


A facility is the term used to summarise units which can - either individually or in combination - be used to produce, store or consume power, natural gas or LNG.


The following primary energy carriers are differentiated with regard to the publications for power production:

  • Biomass
  • Coal-derived Gas
  • Gas
  • Geothermal
  • Hard Coal
  • Lignite
  • Marine
  • Nuclear
  • Oil
  • Oil Shale
  • Other
  • Other Renewable
  • Peat
  • Pumped Storage
  • Run-of-River
  • Solar
  • Waste
  • Water Reservoir
  • Wind (Offshore)
  • Wind (Onshore)
Generating unit

A generating unit for electricity is an energy conversion system which is directly allocated to the main parts of the plant (e.g. to the steam generator, the turbine and the generator in thermal power plants) under the circuit design.

Gross nominal output

The gross nominal capacity of a consumption unit is the continuous capacity which - including the operating and own consumption - is taken from the supply grid. In this context, the fact that the nominal conditions refer to an annual average is of major importance.

Marketing (Predominantly for free / Predominantly not for free)

Generation units which are pedominantly not available for free marketing are for instance "must run", customer controlled and other market price controlled plants (plants under CHP law, industrial plants, etc.).

Net nominal output

The net nominal output of a generating unit corresponds to the highest maximum output under nominal conditions, which is delivered to the public supply grid net of the operating and own consumption of the plant. In this context, the facts that the nominal conditions refer to an annual average, i.e. that the seasonal impact (e.g. the cooling water and air inlet temperature) and the own requirements in terms of electricity and steam offset each other, and that ideal-typical conditions during acceptance measurement, such as e.g. special closed loop circuits, have to be converted to normal operating conditions are of essential importance.

Nominal output

The nominal capacity of a unit refers to the maximum continuous capacity under rated conditions. Unlike the congestion capacity, the nominal capacity must not be adjusted to a temporary change in capacity.

Non-available output

The non-available capacity of a unit is the capacity which cannot be used at the respective time because of the technical and operational condition of the unit.

Non-deployable output

The non-deployable output of a unit is defined as the share of the available capacity which cannot be used as a result of external influences, i.e. of influences whose causes lie outside the plant. This exclusively includes the following:

  • Stretch-out in nuclear power plants for higher fuel utilisation
  • Deviating fuel quality (e.g. coal with a calorific value which is too low)
  • Interruption of the gas supply
  • Congestion/work on the grid
  • Reduction in the electricity output of multipurpose generation units to the benefit of other purposes (e.g. heat extraction)
  • Delays in commissioning of new units
  • Commissioning and trial operation of units in which the operating performance is determined by the trial programme
  • Conditions or missing operating permits (e.g. for reasons of environmental protection)
  • Reduction in the output of units as a result of the required transition from continuous flow cooling to cooling tower operation, lack of cooling water or cooling water which is too warm
  • Preservation of units as a result of which these can only be used again in the long run
  • Strike and force majeure
Non-usable output

The non-usable output of a unit is defined as the capacity which cannot be used at the respective time and which results from the technical and operating state of the unit as well as of further external factors limiting the capacity.

On principle, the classification as a planned or unscheduled non-usability is determined on the basis of the difference between the reporting time and the beginning of the non-usability. If the message is issued before the beginning of the event or concurrently with it, the non-usability is classified as a planned non-usability. A message which is issued after the beginning of the event is classified as an unscheduled non-usability. This has to be considered, in particular, with regard to the beginning of reporting by a new reporting company.

A non-usability, which is reported for the first time, typically begins in the current year or in the following year. A non-usability ends, at maximum, on 31stDecember of the third subsequent year following the current year (e.g. current year: 2015, third subsequent year: 2018).

Non-usabilities can have a status "Active" or "Inactive".
Generally the status is "Active". This means the non-usability will take place accordingly or has taken place already.
A switch of a message status to "Inactive" means that the non-usability has not and will not take place. 
Should a non-usability be concluded early, the value regarding “Time and date of end” will have been adjusted by the corresponding reporting company.

Operating output

The (gross or net) operating output constitutes the output the unit provides at the respective time.

Power plant

A power plant is a facility which is designed to generate electricity by converting energy. A power plant can consist of several generating units.

Power plant operator

Power plant operators are natural persons or legal entities and associations of individuals exercising material influence on the condition and the operation of the power plant.


Price data are shown for the day-ahead and intraday markets of Austria, Germany and Switzerland operated by EPEX SPOT.

The day-ahead auction for Switzerland closes daily at 11 am (CET/CEST) and for the joint market area of Germany/Austria at 12 pm. Although the price determination will immediately started after that gate closure and the results are published in accordance to the auction rules at EPEX SPOT’s website, the publication at the EEX Transparency Platform will be done simultaneously with the disclosure of the forecasted in-feed of wind and solar energy and the planned power production daily at 6 pm.

The intraday prices are taken from the weighted average figures of all transactions calculated for the continuous trading in frequent intervals by EPEX SPOT and published on its website. The figures shown on the EEX Transparency Platform include the hourly contracts only, and are disclosed one hour after the passed operational hour.

Primary energy carriers

The following primary energy carriers are differentiated with regard to the publications for power production:

  • Biomass
  • Coal-derived Gas
  • Gas
  • Geothermal
  • Hard Coal
  • Lignite
  • Marine
  • Nuclear
  • Oil
  • Oil Shale
  • Other
  • Other Renewable
  • Peat
  • Pumped Storage
  • Run-of-River
  • Solar
  • Waste
  • Water Reservoir
  • Wind (Offshore)
  • Wind (Onshore)
Pumped storage power plants

Pumped storage hydro power plants comprise generating facilities (turbine operation) and consuming facilities (pump operation), which are used depending on the requirements of the market in which the respective power plant is used. Pumped storage hydro power plants without a natural inlet have an available capacity of 0 MWh since the turbines can only be operated if capacity was created through the operation of the pumps in advance.

Data are provided in the section of power production and power storage.


The redispatch by power plants is a grid-related measure to remedy unscheduled and unforeseeable grid bottlenecks (e.g. on account of unscheduled failures of other power plant blocks and/or extra-high voltage lines). From a grid perspective, redispatch is an intervention into the schedule of the operator and is therefore not a non-usability to be reported. The publication of redispatch measures is generally carried out by the initiating transmission system operator as a grid measure.


Temporary switching-off of the facility or unit for technical, operational or commercial reasons.


A site consists of one or several power plants. Because of historical reasons, different ownership situations or various energy conversion processes the generating units available at one site can also be assigned to several power plants.

Start-up and shut-down ramps

Changes to the output of generating facilities are usually made through increases or reductions of the fuel supply (in the case of wind, water and solar power through changes of quantity, speed, intensity, etc.). A change of the output from 0 to 100% in 0 seconds is physically impossible, changes are made on the basis of plant-specific gradients (speed of output change). The gradients are e.g. established on the basis of the type of construction, construction size, control technology, fuel, operating condition, air pressure, temperature, etc. In case of a default in operation, there are further dependencies e.g. on the basis of safety aspects. As a result, these gradients cannot be planned in advance in the form of ramps but essentially evolve depending on the respective situation. For the wholesale market, the ramp length is basically only relevant in the intraday segment with relevance for the balancing energy market predominating clearly.

Moreover, the usual long start-up and shut-down ramps which are common in the field of nuclear energy are difficult to represent in detail in planning. However, reporting of the expected available output as an average for the day is possible and provided in the context of the "Forecast of the Maximum Available Energy" and "Available Generation Capacity".


A unit is the smallest technical unit for which messages regarding the production, storage or consumption of power, natural gas and LNG are submitted. Several units are summarised into one facility.

Usable output

The usable output of a unit corresponds to the difference between the net nominal output and the output which cannot be fed into or taken from the transmission system for technical reasons and/or reasons which lie outside the unit. In deviation to the non-available output, the non-usable output also takes reasons for the restriction of the possible output fed into or taken from the grid which are external to the units into account.

The same definition applies analogously with regard to the possible maximum injection or off-take of natural gas units.

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T:  +49 341 2156 233