Gas-insulated substation (GIS)

A gas-insulated switchgear structure that has been specially developed for use in substations. This construction method reduces the volume of the substation, meaning that a much smaller floor area is required than previously. This therefore makes the substation suitable for installation at locations with limited space.

Generation unit

A generation unit for electrical energy is a component of a power plant that can be defined by certain criteria. This could for example be a block-unit power plant, a busbar power plant, a combined cycle facility, a wind turbine, a machine unit in a hydro-electric power plant, a fuel cell stack or a solar module.

German Renewable Energy Act

The German Renewable Energy Act (Erneuerbare-Energien-Gesetz or EEG) prescribes the preferential inclusion and remuneration of renewable energy generated from hydropower, wind power, biomass, landfill gas, sewage gas, mine gas and photovoltaic systems by the relevant system operators. Since January 1, 2017, the level of remuneration has not been determined by the state, but by tenders. The EEG obliges the transmission system operators (TSOs) to equalize the load of the electricity volumes fed into the grid and the remuneration. As a result, the TSOs market the EEG electricity on an energy exchange. The income generated from this and from the EEG surcharge are used to cover expenses (essentially the remuneration payments).

Grid connection

The network or grid connection refers to the technical connection of consumer installations to a grid.

Grid connection point (GCP)

The grid connection point is the point at which the connection facilities of a grid user are connected to the grid. In the case of connecting offshore wind farms, this refers to the point of intersection between the offshore wind farm and the grid connection system.

Grid connection regulations

Minimum technical requirements for the connections to the grid.

Grid connection system (GCS)

The umbrella term for all installations used for the transmission of electrical energy between the network connection terminal of an offshore wind farm and the grid connection point using the transmission network. If only three-phase electric power is used for transmission, then this is called an AC grid connection system. If direct current is used for at least one section of the transmission path, then this is called a DC grid connection system.

Grid connection terminal

The grid connection terminal is the point where a grid user’s connection system is linked to the grid. For the grid connection of offshore wind farms, this refers to the point of intersection between the offshore wind farm and the grid connection system.

Grid enhancement

Grid enhancement measures are those that deal with the replacement of operating equipment for more powerful components, the extension of existing transformer stations and substations, e.g. with additional switchgear devices and/or power busbars as well as the construction of power lines in existing routes. These measures are represented in the diagrams with solid blue lines or filled-in areas.

Grid expansion

Grid expansion measures describe the construction of transformer stations and substations or power lines in new routes. A yellow shaded area is used to represent these measures in the diagrams of the Network Development Plan. The addition of transformers, facilities for reactive power compensation or operating equipment to control active power in existing transformer stations or substations is represented in the maps with yellow shaded areas with blue borders, these fields are marked with “Expansion of existing facilities”.

Grid interconnection point (GIP)

A grid interconnection point couples parallel offshore grid connection systems longitudinally to form an offshore grid and third-party grids laterally, such that a grid connection system can be operatively connected to grid connection points of seperate systems. A grid interconnection point can, for example, be located on a converter platform or a collection platform.

Grid optimisation

Measures for grid optimisation include changes to the grid topology and the power flow, changing the voltage from 220 to 380 kV or weather-dependent line operation with the aim of operating the existing grid without congestion.

Grid security

Network security, in the sense of ‘security of supply’ and ‘safe system operation’, describes the capability of an electrical supply system to fulfil its duties of transmission and supply at a given time.

Gross output

The gross output of a generation unit is the amount of power output at the generator terminals. The energy demand of the generation facility itself (e.g. for pumps or cooling towers) is not yet taken into account. In contrast, the net output takes the plant’s own energy consumption into account.