They require little space, make no noise and can be hidden behind hedges: large-scale electricity storage systems. Massive performance is hidden in monotonous containers – which will be necessary in the energy transition.
When the wind doesn’t blow and the sun doesn’t shine, electricity increasingly comes from batteries. In many places in Germany, large battery storage systems are currently being built that can absorb green electricity from solar systems or wind turbines for a few hours. The company Eco Stor, which specializes in battery storage, will be building a particularly large storage facility in Trossingen in Baden-Württemberg in the coming years, as was announced on Tuesday.
For a long time, these large-scale battery storage systems hardly played a role – now they are seen by some as a key to the energy transition. Because an increasing proportion of electricity comes from renewable energies; In the first half of the year, their share of net electricity generation was already 65 percent, according to the Fraunhofer Institute for Solar Energy Systems ISE. In times of darkness or calm winds, these large storage systems can feed electricity back into the grid. They can react in fractions of a second and have a high efficiency of 80 to 90 percent.
It’s easy to make money by saving
Large-scale storage systems in Germany currently have a capacity of 1.8 gigawatt hours (GWh), as shown by the battery charts from RWTH Aachen. Eco Stor is currently building 238 megawatt hours in Bollingstedt, Schleswig-Holstein, and in a few weeks construction will begin on a storage facility of the same size next door in Schuby. In total, the company has more than two gigawatt hours in the pipeline – this alone is likely to soon double large-scale storage capacity in Germany.
The Volkswagen Group also plans to start building a 700 megawatt-hour storage project this year. Additional large-scale storage facilities are being planned or already being built by, among others, the energy suppliers RWE, LEAG, EnBW and the company Kyon Energy, which was taken over by Total Energies. Most companies rely on lithium-ion batteries – like in electric cars.
According to experts, the fact that so many companies are currently interested in battery storage is due to the fact that they can now be built fairly cheaply – and therefore make a lot of money. “There was a big cost reduction for lithium-ion batteries,” says Gunnar Wrede from the Federal Association of Energy and Water Industries. “Ten years ago, the battery alone cost three to four times as much per kilowatt hour.” The price decline was more rapid than assumed in many scenarios.
With the batteries, electricity can be bought cheaply on the stock exchange, for example at midday when the solar parks are working at maximum capacity, and sold again later in the evening when the price of electricity on the stock exchange is high. This means that electricity storage often pays off even without subsidies. Wrede also points out that electricity storage operators often no longer have to pay additional network fees. Batteries are also subsidized in surcharges and electricity tax is not levied.
Built quickly, refinanced quickly
Compared to pumped storage, which pumps water upwards to generate electricity when needed, batteries have another big advantage: the planning procedures are less complex and lengthy – and they don’t have to be operated for decades before they are refinanced. The containers in which the batteries are located are pre-produced and delivered turnkey. The operators only have to build the foundation themselves. And a strong electricity connection is necessary, which is why the large energy companies are also relying on old power plant locations, such as coal and nuclear power plants that are being phased out.
Dirk Uwe Sauer, who holds the chair for electrochemical energy conversion and storage system technology at RWTH Aachen University, expects at least ten gigawatts of additional battery power for delivery times between one and four hours in a few years.
What’s more: storage at solar parks, where their electricity is temporarily stored. “This means we can push the feed-in,” explains Rashid Elshahed, EnBW group press spokesman for renewable energies. “Since electricity prices fluctuate so much, it’s much more economical.” According to a study by the Fraunhofer Institute for Solar Energy Systems ISE, the companies’ photovoltaic battery combinations can now produce electricity more cheaply than coal and gas power plants.
Still a lot of room for improvement
But are the projects planned now enough? Fraunhofer ISE assumes that Germany will need a full 180 GWh of centralized and decentralized electrical storage by 2045 – and even with that, Germany’s electricity needs could only be covered for half a day from electricity storage on an average winter day.
The Federal Network Agency also assumes in its network development plan that up to 113 GWh of photovoltaic battery storage and 55 GWh of large battery storage could be installed in the specified period. What is particularly important is more flexibility and the use of small storage systems to benefit the system, says Markus Doll, Head of Networks and Systems at the Federal Network Agency. Such small storage systems are installed on photovoltaic systems in houses, for example. According to the battery charts, the capacity of these home storage systems is already far higher than that of large storage systems, namely a total of 12.6 GWh.
E-cars could play a central role
University professor Sauer also sees this flexibility as a key. “You could ramp up and down consumers, for example the electric vehicle fleet,” he says. However, so far only very few vehicles and house connections allow this option. Electric cars alone have enormous potential: If there were 20 million electric cars, each with a 60 kWh battery, they would have a total capacity of 1,200 GWh, which could provide up to 60 GW of power. “With these cars, you could charge around 20 percent in and out every day without the battery seriously aging, and that’s more than the average household uses.”
The advantage of these decentralized solutions: The storage systems are already located where the electricity is needed. “A central gigawatt storage system is of no use if there are network bottlenecks and the electricity cannot be delivered to households,” says Sauer. But in order to be able to use these local storage systems and cars, a lot of digitalization is still missing, for example in the form of smart meters for recording power flows and prices. “But in principle it would work and is already being demonstrated in pilot plants.”
Sauer thinks these large storage facilities are okay as an interim solution. These only lasted ten to twenty years anyway. By then, digitalization will hopefully have become established and then all flexibility can be used. “I would like us to use these posts that we already have. Batteries also break if they just sit there.”
Energy charts: Battery storage in Germany Scenario framework Network expansion plans by Ecostor BDEW: Storage strategy Network development plan 2023-2037/2045 Fraunhofer ISE: Large-scale battery storage Kyon Engery Project from Enerpac LEAG to Boxberg with GigaBattery Fraunhofer ISE: Public net electricity generation 2024 Electricity storage strategy of the federal government Fraunhofer ISE: Photovoltaics with battery storage cheaper than conventional power plants EnBW: Battery storage Total Energies on their storage projects
Source: Stern
