Whit Monday, June 6, 2022 — a wonderful sunny and pleasantly windy day. Not only perfect for a holiday walk with the family, but also perfect conditions for photovoltaic and wind power plants, which managed to single-handedly provide all required electricity on this day. Around lunchtime, the entire 48.7 GW of electricity required in Germany could be covered by 54.5 GW of solar, wind, biomass and run-of-river hydroelectric plants without any problems. As many as 5.8 GW more was produced than was consumed.
Absolutely, but with a bitter aftertaste. As can be seen in the following graph, renewables were able to completely meet demand, but conventional power plants such as coal, gas or nuclear power could not be shut down at the same time.
Due to the lack of flexibility in the German power grid and the inertia of large conventional power plants, which could not be shut down quickly enough, a significant surplus of electricity was produced on this day.
In addition to the 54.5 GW mentioned above, 7.9 GW from brown and hard coal, 2.2 GW from nuclear power and even 2.5 GW from the generation of currently very scarce natural gas. Germany therefore produced a surplus of 19.3 GW at that time. As a result of this mismatch between electricity supply and demand, the electricity price plummeted from around 94€/MWh to -0.08 €/MWh. Germany therefore had to give away electricity to neighboring countries in order to keep the electricity grid in balance. Just a few hours later at 20:00 as soon as the sun set, brown coal production had to be increased from 6.3 GW to 13.8 GW in order to meet demand. The price of electricity rose sharply to 215 €/MWh.
Within a few hours, Germany first had to give away excess electricity from renewable sources and shortly thereafter ramp up production from brown coal by more than double to meet demand.
06.06.2022 therefore impressively demonstrates the critical problem still to be solved in the energy transition:
The lack of flexibility in the German power grid.
In order to be able to achieve the climate target of 80% renewable energy by 2030, it is essential to significantly increase this flexibility and thus prepare the network for much higher quantities of renewable generation plants in the future.
In order to effectively balance out volatility, the power grid must be able to react much more flexibly to fluctuating production from renewable energy sources in the future. For this, you must energy storage systems become an integral part of the network of all types. With the help of these systems, the surplus energy could have been absorbed first on this Whit Monday and fed back in later, which would have avoided the spike in lignite output and the sharp price fluctuations on that day. More about network flexibility can be found in the glossary entry”flexibility (energy system)“to find.
One of the key technologies in the area of storage systems that address exactly this problem is stationary, grid-connected large battery storage.
These large battery storage systems are, as the name suggests, large-scale battery storage systems that are connected directly to the grid and often range in the range of 5 — 100 MW. Thanks to their high efficiency levels (over 90%) and extremely fast responsiveness (full power is available within fractions of a second in case of doubt), these storage systems are very suitable for compensating for short-term fluctuations in the power grid.
In the specific case of Pentecost Monday 2022, the large storage facilities would therefore use the low prices at 12:00 to recharge and the expensive prices at 20:00 as soon as the sun set to unload. As a result, the batteries would absorb excess energy from renewables and both reduce price fluctuations on that day and avoid the start-up of lignite-fired power plants.
In addition to this market-friendly behavior, large battery storage systems can also simultaneously take on other critical, grid-related tasks of the power grid, which keep the future volatile power grid flexible, stable and secure:
Control energy:
Control energy serves as a reserve to compensate for any fluctuations in the power grid frequency in a short period of time (seconds to minutes) and to maintain a constant frequency of 50 Hertz. Power generation and consumption are then always in balance.
--> Stabilizes the power grid even with a high percentage of renewable generation plants
Black start ability:
Ability to rebuild the grid without an external power supply in the event of a complete power failure (many conventional large power plants require electricity to restart themselves)
--> Secures the power grid and prepares it for a potential emergency.
Avoiding bottlenecks (redispatch):
Intervention by the network operator to avoid power overloads in the power grid. Systems are booted up or shut down as required to avoid overloads.
--> Reduces the need for further physical network expansion and helps to evenly distribute the load in the power grid. (Reduces the North-South bottleneck, for example)
Power required to set up our AC network (development of magnetic fields in transformers, inverters, etc.)
--> Assists in setting up and stabilizing our power grid
Electricity trading/balancing price peaks:
Absorption of electricity at low prices (= often surplus of renewables) and feed-in at high prices (= often too little renewable energy available).
--> Stabilization of volatile electricity prices
--> Increasing the flexible use of renewable energy through intermediate storage
The Fraunhofer ISE study “Paths to a Climate-Neutral Energy System” from 12.11.2021 also shows that stationary large battery storage systems will play a key role in the energy transition due to this possible diversity of network-serving tasks.
If we in Germany want to obtain even 65% of our energy from renewable sources by 2030, it is inevitable, according to the study, to expand the battery storage capacity in Germany to 83 GWh and thus almost 200 times the current capacity and thus prepare the grid for this number of volatile generation plants. If the 80% currently planned in the federal government's latest Easter package is therefore to be achieved by 2030, this expansion just needs to be tackled more quickly.
Without the flexibilization and stabilization of the German power grid through a significant expansion of large battery storage systems and other storage systems, the rapid expansion of renewable sources by 2030 will regularly result in days such as Whit Monday 2022, during which the power grid will not be able to meet the demands of fluctuating production and will therefore both be unable to effectively use valuable electricity produced and jeopardize the stability of the power grid.
However, if we manage to remove the current bureaucratic hurdles, such as the recognition of the ability of large battery storage systems to serve the grid, which are currently slowing down expansion, we will come a long way closer to a 100% renewable energy system.
.png){kind=logo}
