The Residual load is a term from the energy sector, particularly in the context of electricity supply. It denotes the difference between actual electricity demand (consumption) and available electricity generation at a specific point in time. In an electricity grid, supply and demand should be as balanced as possible at all times, as electricity cannot be stored in significant quantities.
Electricity generation must therefore always match current consumption, with the residual load being zero. However, this is difficult in practice, as electricity generation from renewable sources such as wind power or solar power is highly dependent on weather conditions and is not constant. Therefore, they are also referred to as volatile energy sources. A residual load occurs when the controllable electricity generation (e.g., coal, gas, or hydropower) is insufficient to meet current total demand.
In such a moment, additional measures must be taken to close the supply gap. An acute energy shortage (Positive residual loadFor example, the use of peak load power plants, the import of electricity from other grids, or the reduction of demand through load management can counteract this. In a negative residual load, This means there's an excess of electricity, which must either be sold abroad or stored. In exceptional cases, transmission system operators (TSOs) will then disconnect power plants from the public grid.
Within the framework of Redispatch 2.0 The operators concerned then receive compensation for the shutdown of their facilities. They receive this compensation either directly from the grid operators or indirectly from the respective direct marketers. Since the residual load can vary greatly depending on the time of day, weather conditions, day of the week, and other factors, it is monitored minute by minute. The so-called German federal dispatch recalculates it from day to day.
The residual load presents new challenges for electricity procurement.
So that the daily recalculations can be performed, all data from all power generators (including photovoltaic systems from 100 kWp onwards, which have a grid connection) and the daily energy consumption forecast of all consumers are fed into the transmission system operators, who use this information to plan reliable power generation and supply for the next day.
Energy purchasers for energy-intensive companies with their own power generation must therefore submit a forecast notification that takes their own residual quantity into account. This means they must calculate the company's remaining electricity demand, which remains after deducting the self-consumption of renewable energy and is to be covered by conventional power plants.
This presents energy procurement. new challenges. He must now consider the specific load profile of his own company with the PV yield forecasts contrast with one's own electricity production. In addition, a procurement strategy is necessary to cover the energy demand. An exact calculation of the residual amount and advance notification to the respective energy supplier are essential. Incorrect calculations can lead to high costs. Overestimated grid consumption will not be refunded. If higher grid consumption is necessary than previously announced, the electricity costs for it can also quickly multiply.
Location-specific weather forecasts help with calculations
Since renewable energies like wind and solar power are volatile, site-specific weather forecasting is extremely important when calculating residual quantities. Even during the planning of a commercial photovoltaic system, it is possible to achieve relatively accurate predictions based on the solar cadastre, module orientation, and components. Annual yield will be calculated. This alone allows the residual loads to be well constrained. This gives energy purchasers a rough overview of how much additional electricity they need to purchase or can feed in. In addition, larger PV systems are constantly monitored, their electricity generation recorded, and their systems can be intelligently Software solutions with accurate weather forecasts Calculate redemption in advance. This significantly simplifies the calculation.