As early as 2021, the Fraunhofer Institute ISE, in the course of its study "Paths to a Climate-Neutral Energy System", forecast an almost 200-fold increase in the expansion of short-term storage from 2021 to 2030 in order to prepare the nationwide power grid for the energy transition.
This assessment of the research is now also acknowledged by the regulatory authorities in the course of the latest scenario framework for the grid development plan published every 2 years. This is prepared in cooperation between the transmission system operators, responsible for the nationwide transport of electricity over long distances, and the Federal Network Agency, the national regulatory authority for the electricity grid. The grid development plan defines the measures that are necessary now and in the near future to prepare the power grid for volatile renewable energy generation. The scenario framework provides the necessary numerical basis for this.
Large-scale battery storage was already taken into account in the 2021 grid development plan, but with a rather conservative expansion expectation of 3.4 GW by 2035. In the scenario framework for the 2023 grid development plan that has now been published, however, these forecasts were increased 7-fold to 24.2 GW by 2037 and are now similar to the Fraunhofer Institute's figures.
Regulators have now also recognized the need for the widespread expansion of large-scale battery storage, which is essential to effectively compensate for the increased generation volatility caused by the massive increase in the share of renewables.
Why was the forecast increased so much?
In the current grid development plan, the assumption of how large-scale battery storage can be used was adjusted. Instead of limiting the use of storage facilities to the provision of balancing energy, the current plan also takes active participation in the electricity market into account. With this assumption, the actual use is represented much more realistically, since especially the modern large-scale battery storage systems (see www.kyon-energy.de) focus on a multi-use strategy and not only on the balancing energy market.
The regulatory authority's assumptions have therefore now come closer to those of the scientific community. The next step, however, is to answer how the BNetzA intends to turn these forecasts into reality, i.e. how storage systems are to be integrated into the grid.
According to the current regulatory policy of the BNetzA, storage systems are considered to serve the market only and thus, from a regulatory point of view, to clearly burden the grid and not to serve the grid, even though, as described in our article "How energy storage systems avoid blackouts", they have the technical prerequisites to make a major contribution to grid stability.
If storage systems continue to remain a burden on the grids from a regulatory perspective, the forecasts that the BNetzA itself has now confirmed will never be realized in reality. To ensure rapid and large-scale storage expansion and thus achieve the goals it has set itself, the BNetzA must act now:
The prerequisites for a grid-serving use of storage systems must be clarified. Then grid operators will also be certain that large-scale storage expansion will not result in grid expansion, but on the contrary can avoid nonsensical grid expansion "down to the last kWh". This would enable grid connection for many gigawatts of storage systems and an important milestone on the way to an energy system with 80% renewables in 2030 would be achieved.