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Flex­i­bil­i­ty in the electricity sup­ply sys­tem

When talking about the energy transition, we often hear about the increasing need for the use of flexibility to be able to efficiently guarantee the security of supply.

Bundesnetzagentur's discussion paper

Flexibility in the electricity system - Status quo, obstacles and approaches for a better use of flexibility (pdf / 516 KB)

The aim of this Bundesnetzagentur's publication – as with its previous discussion papers on network charges and smart grids and smart markets – is to take up and shape the current debate about the energy system and to highlight a number of points that are important from the perspective of network regulation.

The precondition for a secure supply of electricity is, in the first instance, a balance of electricity generation and consumption at all times. This balance is ensured through the electricity market.

Challenges posed by the energy transition

In the past, it was primarily the load to be met that was unplannable and unpredictable. In the wake of the energy transition, however, variable and intermittent generation from renewable energy sources is becoming increasingly important. In the medium term, more than half of the electricity generated is expected to come from renewables. As the percentage of renewables in the electricity mix rises, the residual load can frequently decrease to almost zero and then increase significantly within a short window of time – either days or hours. The actors in the system therefore need more flexibility to be able to efficiently guarantee the security of supply. This flexibility includes interactions with our electrical neighbours. Imports and exports at cross-border interconnectors are an essential element of a flexible energy system.

Main points of the discussion paper

Many of the key propositions put forward in the paper will be of no great surprise, given the previous opinions expressed by the Bundesnetzagentur. However, as these propositions are indispensable for functioning energy markets and a successful energy transition, they bear repeating very clearly. This includes adhering firmly to competitive solutions, which respond to price signals from the market, and the explicit refusal to grant specific support to individual players in the electricity market.

At the same time, the Bundesnetzagentur is open to a discussion on whether and to what extent network operators should take the scarcity of network resources into account and should be enabled to reflect these scarcities through improved tariff structures. In nearly every case, network expansion remains the most viable solution for a volatile energy system that is to combine low CO2 emissions, and eventually zero CO2 emissions, from electricity generation with security of supply and affordable prices.

Defining flexibility

Flexibility in the electricity supply system has become a buzzword. The term flexibility can mean many different things.

Flexibility is the modification of generation injection and/or consumption patterns in reaction to an external signal (price signal or activation) in order to provide a service within the energy system.

The parameters used to characterise flexibility include the

  • amount of power modulation
  • duration
  • rate of change
  • response time
  • location