Shadow power plant

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With shadow power plants are power plants called out ready to energy demand by the prolonged outage of a power generator in the electric power grid to cover. Short-term demand is covered by peak load power plants. If the demand drops sharply, power plants must be throttled further. There is also the cold reserve , i.e. power plants that have been shut down for a longer period of time, which mainly come into play over the course of the season.

Wind power feed-in e.on control area

Exactly as much energy must always be generated in the power grid as is consumed at the same time. Therefore, the energy consumption and also the generation in wind turbines and photovoltaic systems are forecast as well as possible. If there is no generation of renewables, power reserves of conventional power plants must be available for a short time to cover the load. The prognosis is still never accurate. There are always deviations from the forecast energy demand and the performance of wind turbines and photovoltaic systems also deviates from the forecasts. Control power must be available to compensate for forecast errors ; this is also mostly generated in conventional power plants. In addition, flexibility reserves are increasingly being raised from load control.

The output of steam power plants cannot be changed at will and quickly; In addition, minimum operating and minimum downtimes must be observed to avoid excessive system wear.

Course of the springtime electricity consumption (load) over different days of the week and use of base, medium and peak load power plants on the load course on weekdays (schematic, according to EWE)

Shadow power plants are also known as “hot reserves”. These are conventional power plants that are available in permanent operation with minimum output, because after they have been switched off, a certain minimum period must be observed until the next start-up (see table below). If necessary, these power plants can then be ramped up to full load . Partial load operation always results in a lower degree of efficiency and thus higher costs and a poorer environmental balance.

Power plant type Start-up time
in h 		Minimum
performance
in% 		Minimum
downtime
in h 		Minimum
operating time
in h 		Loss of efficiency
at P min
in percentage points 		Speed ​​of
power change
in% per minute
Natural gas GT 0 20th 0 1 22nd 20th
Natural gas station wagon 1 33 2 4th 11 6th
Natural gas DT 1 38 2 4th 6th 6th
Bituminous Coals DT 2 38 2 4th 6th 4th
Lignite DT 2 40 6th 6th 5 3

Battery storage power plants react the fastest , then pumped storage power plants (dams) and gas turbine power plants . The latter have relatively high fuel costs, but are comparatively less capital-intensive to manufacture.

See also

Individual evidence

  1. ↑ ier.uni-stuttgart.de (PDF; 5.0 MB) Compatibility of renewable energies and nuclear energy in the generation portfolio