Peak capping

Peak capping describes the curtailment of infeed peaks from onshore wind farms and photovoltaic power as part of network planning. It is a planning tool used for dimensioning the grid and does not denote any actual intervention in the energy feed-in (see ‘Infeed management’) which makes it possible to avoid expanding the grid to cater for rarely occurring peaks in energy infeed.

Peak load
The peak load is the maximum output that can be withdrawn by a consumption device or procured through the supply network during a given period of time (e.g. day, month, year).
Point measure

In addition to power line construction measures, so-called ‘point measures’ are also required as part of the Grid Development Plan; these include transformers, reactive power compensation facilities and substations. A distinction is drawn between vertical point measures (additional demand for 380/110 kV transformers between the extra-high voltage grid and the high voltage grid) which are identified in the GDP in consultation with the distribution network operators, and horizontal point measures (e.g. 380/220 kV transformers, reactive power compensation facilities, phase-shifting transformers) which concern the extra-high voltage grid exclusively.

Power station

A power station is a facility that has been designed to convert energy from a primary or secondary energy source to produce electrical energy.

Power station operator
Either through ownership or contract, a power station operator possesses the capacity of a power station and can determine how it is used.
Power-frequency control

The power-frequency control refers to a regulating process used by the TSOs so that they can adhere to the agreed upon quantities of electricity at the borders of their control areas in times of normal operation and particularly in the event of any system failure. Each TSO strives to keep the exchange capacity within the agreed limits with respect to the other control areas as well as ensuring that the network frequency stays as close to the set value as possible; this is all done by the use of an appropriate contribution from their own control area.

Primary control

The primary control limits frequency fluctuations, which occur due to the failure of generating units or sudden changes in the consumption load, within seconds. It is automatically activated within thirty seconds whenever a large frequency deviation occurs. Regardless of where the malfunction occurs, all power stations in the European synchronised integrated network support this frequency stabilisation.

Primary energy
Energy that is available from naturally occurring energy types or sources, for example, coal, gas or wind. This differs from secondary energy, which is only made available through the conversion of primary energy.
Project of Common Interest (PCI)

In 2013, the European Commission published a list of projects of European importance entitled Projects of Common Interest (PCI). This list includes around 100 electricity transmission projects throughout Europe. Implementing Projects of Common Interest is to be given top priority. The criteria for selecting a project were: it provides a substantial benefit to at least two EU member states, it helps to strengthen the European single market, it increases the security of supply and it reduces CO2 emissions.You can find out more about PCI projects on the European Commission’s website here: