Peaking power plant

Peak load referred briefly occurring high power demand on the power grid or other supply networks ( gas, district heating, district heating ).

Demand peaks are often characterized by a strong increase in the demand power so that the power supply quickly adjustable peak-load power plants must be used. These can provide high performance available within seconds or minutes. These include pumped storage and compressed air storage power plants, but also modern gas turbine power plants.

Power plant management and peak load

To ensure the supply at all times even with fluctuating power consumption (security of supply ), a power plant management with tips is necessary. From the perspective of power network management, there are three types of power plants, which are used in different ways in the load curve:

  • Base load power plants (nuclear power plants, lignite power plants, hydroelectric power plants) are, around the clock as far as possible, operate with full load. They can generate electricity relatively inexpensive, but can be adjust only slowly. In case of failures in the power plant area must be here shortly reserve power can be made ​​available to other power plants can take over power generation. Just out of unscheduled outages larger generator units, this is not always possible.
  • Medium load power plants (eg coal power plants ) vary their power according to the predictable current need for a predetermined daily schedule. They have average electricity production costs and can be controlled over a wide power range, however, the control acts with a certain inertia. To rapid changes in electricity demand can respond only partially; this must be prevented by peak-load power plants.
  • Peak load power plants ( pumped storage power plants, compressed air storage power plants, gas turbine power plants) can rapidly follow changes in network performance. Gas turbine power plants achieve change speeds up to 20 % of rated power per minute and have a startup time of only a few minutes. The power can be controlled between 20% and 100 %. They are used to equalize the fluctuations in power demand and supply of producers that can not be compensated by the other types of power plants, or where this is not economically sensible. Peak load power plants only a few hours per day are usually used: the peak demand, with strong increases in load on the network and unplanned fluctuations of electricity consumption and generation. Through the consumption of natural gas or pumping energy of the electricity generated by them is significantly more expensive than the other types of power plants.

Renewable power generators such as solar panels, wind turbines and the majority of the CHP are currently (2012 ) not included in the active network control, apart from forced shutdowns by system operators in problem situations. These producers dine on renewable basis by law usually the entire electricity generated to the grid (priority feed ). Thus they displace mainly medium-load power plants ( (photovoltaic noon) also displaces peak load power plants), thus lowering the price of electricity on the electricity exchanges. However, fluctuations in the power generation of these power plants must often be balanced with the help of peak load power plants, which in turn causes additional costs. The adaptation of the timetables of the medium load power plants to projected power generation has become more complex due to the fluctuating renewable electricity producers; the forecasts have become more accurate.

At present ( 2011) to develop a methodology to intercept peak loads locally. So -called load managers can for example be installed or be compensated by hybrid inverter short-term generator and load variations of photovoltaic systems in households.

Predictable peak load

The increased power demand during the day is very predictable in general. The course of the demand over the day is known. They all year reached the highest values ​​between 11 and 14 clock ( up to 82 GW in Germany, 1 NPP = 1.2 GW ), from mid- October to late March also often between about 16:30 and 19 clock. Similarly, there are fairly accurate predictions regarding the current injection of third parties ( eg predicting the supply of wind turbines and photovoltaic systems due to current weather forecasts ). Timetables for the medium load power plants are created from the expected hourly. Smaller forecast errors are compensated by the so-called control power, which power plant operators have to maintain to varying degrees.

Can not be the expected load curve or not to cover economically medium load power plants, as peak load is used:

  • If at certain times so strong increases in load expected that this can not be handled by mid-load power plants, as peak load power plants are planned to support for that period.
  • Are current spikes so short that it this would not be economical to boot a medium-load power plant, the use of peak-load power plants is planned for this period.

Unpredictable peak load

Due to the failure of a base load or mid- load power plant or an unexpectedly high load on the power supply, the output of peaking plants may be necessary. To cope with acute failures of different power plants are used in sequence:

Power exchange

Peak load is often traded on power exchanges, where they can cost several euros per kilowatt hour in extreme cases. At the current stock market is, however, no distinction between peak and medium load. All traded on a daily basis stream is referred to as peak load, such as any daytime increased demand for electricity, which is about 50% at noon on the base load.

At the European Energy Exchange EEX peak load current 8:00 to 20:00 clock is traded in hours packages.

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