The residual load plays a central role in modern energy management, particularly in the context of the energy transition. It describes the difference between the total demand for electricity and energy generation from renewable, weather-dependent sources such as wind and solar energy. As these forms of generation fluctuate greatly, the residual load is a decisive factor for grid stability and the need for conventional power generation.

In an electricity grid, generation and consumption must be in balance at all times in order to avoid grid fluctuations. However, wind and solar power plants do not produce electricity constantly, as their output depends on weather conditions. For example, on a sunny day, the solar power plant can supply a lot of electricity, while solar power is not available when the sky is overcast or at night. The same applies to wind power, which depends on wind conditions. The amount of electricity that is not covered by renewable energies must be provided by other sources - this is the residual load.

In most European countries, including Austria, the residual load is mainly covered by conventional power plants such as gas-fired power plants, coal-fired power plants or hydroelectric power plants. These power plants are able to react flexibly to fluctuations in renewable generation and thus provide the energy required to keep the grid stable. The thermal power plant fleet in Austria plays an important role when it comes to balancing the residual load, especially in times of low feed-in from renewable sources.

A good understanding of the residual load is essential for planning the energy system of the future. As the share of renewable energies increases, the residual load becomes more dynamic and complex. Particularly in times of high feed-in from solar and wind power, the residual load can fall sharply and in some cases even become negative. This means that more electricity is produced at these times than can actually be consumed. Conversely, the residual load increases at times of low renewable generation, which increases the need for conventional generation or other solutions such as storage technologies and demand management.

The future of the energy market lies in managing the residual load through new technologies. Storage solutions such as battery storage, which can store electricity during periods of high production and release it when needed, play a key role here. Pumped storage power plants also have a long tradition in Austria and contribute to covering the residual load by storing electricity and feeding it into the grid when needed. Sector coupling is also becoming increasingly important, whereby different energy sectors, such as electricity, heat and transport, are networked with each other in order to balance out fluctuations.

Another option for controlling the residual load is demand side management. Consumers, especially large industrial companies, can flexibly adapt their electricity demand to the current grid situation. When the residual load is high, consumers can be encouraged to reduce their electricity consumption, while they can increase their consumption when there is an oversupply of renewable electricity. There are already pilot projects in Austria that are based on this concept.

The residual load illustrates the challenges and opportunities associated with the integration of renewable energies into the electricity grid. The higher the proportion of wind and solar energy, the more the residual load fluctuates and the greater the need for flexible solutions. Austria is well positioned here compared to other European countries, as it has a high proportion of hydropower, which can also react flexibly to electricity demand. Nevertheless, the task remains to further develop innovative storage solutions and flexible control mechanisms in order to meet the growing requirements.

Overall, it is clear that the residual load is a central element in the electricity supply system of the future. It makes it clear that even in a system increasingly based on renewable energies, conventional power plants, storage technologies and flexible control systems will continue to play an important role in ensuring the stability and security of the energy supply.