A Grid connection point (NVP) is a node in the electricity grid at which various electricity generators, such as wind or solar power plants, as well as consumers and different grid levels are connected. At these points, electrical energy is fed into the grid, distributed or transferred between different grid sections (e.g. between transmission and distribution grids). Typical grid connection points are substations, switchgear or transformer stations, which ensure that the electricity flows safely and efficiently through the grid. Until now, it has been common for grid operators to equip NVPs with a Maximum feed-in power from 100 % prove it.
Long waiting times for the connection at the grid connection point
Because the expansion of renewable energies has accelerated significantly in recent years and the German government aims to source 80 % of electricity generation from renewable energy plants by 2030, the grid connection increasingly frequent bottlenecks. Distribution system operators (DSOs) cannot keep up with the large number of connection requests. This results in long waiting times and increasing distances to the next available grid connection point. In addition, there are long delivery times for transformers and substations, which makes the Increased costs for RE projects and partly even their Realization at risk. The legal framework, which stipulates that every grid connection must be designed for the maximum output of a renewable energy system, also has an inhibiting effect here. In practice, however, this maximum output is rarely reached, as renewable energies such as solar and wind feed in volatile power.
Unused capacities of the grid connection points
If, for example, a ground-mounted PV system with 50 MWp and a wind farm with 100 MWp are connected to a 150 MW grid connection point today, no other generation systems are allowed to feed into the grid. However, as both generation plants will rarely feed 100 percent of their power into the grid at the same time, the remaining time the free capacities unused. The complementarity of intelligently controllable solar and wind energy systems, which generate electricity differently on individual days and seasonally, can distribute the grid load more evenly and reduce the Redispatch be reduced. As a result, very few grid connection points are already fully utilized today.
In order to reduce grid connection costs and not jeopardize the implementation of new renewable energy projects, the question of connecting several renewable energy plants and storage systems together at grid connection points is now under discussion in order to reduce the existing grid connection costs. Use infrastructure more efficiently. Although this cannot fully compensate for the lack of grid expansion, at least the grid operators gain valuable time in this way. Experts therefore recommend connecting several renewable energy systems together to one grid connection point and "overbuilding" it in order to increase capacity utilization.
Oversizing of a grid connection point
The German Renewable Energy Federation (BEE) and the Fraunhofer IEE have now published a Study was carried out. This shows that a moderate Oversizing of the grid connection points (around 150 % of the connected load). This promotes the accelerated expansion of renewable energies. In order to forecast the optimal use of grid connections, the scientists analyzed the feed-in potential of wind and solar energy across Germany. They came to the conclusion that even greater oversizing (250 %) is possible without any problems. This would even lead to a further increase in the efficiency of the grid connection points. Although this would lead to more surplus electricity, this could be used sensibly by storage systems and sector coupling systems such as electrolysers. This would also avoid curtailment of renewable energy plants.
The legal adjustments required to implement these measures are minor and could be implemented quickly. This would allow projects to be implemented more quickly, save costs and resources and create additional incentives for the expansion of storage facilities and flexible biogas plants. Overall, this would accelerate the energy transition and make it more cost-effective, according to the report.
Conclusion
The more efficient use of grid connection points is crucial for accelerating the expansion of renewable energies. In view of increasing connection requests and limited grid capacities, long waiting times and high costs are delaying projects. As solar and wind energy rarely feed their maximum power into the grid at the same time, many NVPs remain underutilized. One solution is to connect several renewable energy systems and storage systems together and moderately oversize grid connection points. Studies show that this would increase efficiency and reduce curtailment. With minor legal adjustments, projects could be implemented more quickly and the expansion of renewable energies could be significantly accelerated.