How battery storage systems contribute to the decarbonization of the power supply

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Germany's decarbonization goals

In order to prevent the worst consequences of the climate crisis, most countries have set themselves the goal of radically reducing their greenhouse gas emissions. The German Federal Government has also once again tightened its binding climate protection target. For example, the Bundestag passed a new Federal Climate Protection Act (KSG) last year. This also includes - Germany's decarbonization goals.
The aim is now to reduce greenhouse gas emissions to minus 65 percent compared to 1990 by 2030, and then greenhouse gas neutrality by 2045.

Energy-related emissions, i.e. emissions that occur when energy sources are converted into electricity and heat, accounted for 83% of Germany's greenhouse gases in 2020. The main source of these energy-related emissions was the energy industry with a total share of 36%. The energy sector is therefore particularly important for achieving the decarbonization goals, as it is Germany's largest producer of greenhouse gases. In the electricity market, the aim is therefore to completely decarbonize as early as 2035.

This is primarily due to the fact that Germany has relied primarily on fossil energy sources for a very long time. As a result of the progressive expansion of renewables, there has also been a downward trend in CO in the energy sector over the last thirty years2 -Observe production. However, as a result of the energy crisis, this trend has (temporarily) reversed and there has been a slight increase in emissions over the last two years. In 2020 alone, the energy industry emitted 212 million tons of carbon equivalents.

So what does it take to achieve these ambitious goals?

The most obvious measure to achieve decarbonization goals in the energy sector is to accelerate the shutdown of conventional power plants and the rapid expansion of renewable energy sources. This is because the burning of fossil and also largely imported energy sources produces the majority of all greenhouse gases. Switching to renewable energy sources is essential. At the same time, the electricity market must also be comprehensively modernized, made more flexible and digitalized in order to keep pace with the expansion of renewables. For this purpose, energy storage systems of all types must also become an integral part of the network.

How do battery storage systems contribute to savingCO2 at?

The aim of decarbonization in the energy sector is to feed a larger amount of renewables into the grid and thus reduce dependence on production from fossil fuels. However, the electricity infrastructure in Germany is not designed for high volatilities and network expansion is lagging behind the accelerated expansion of renewables. This is already resulting in increased grid bottlenecks, shutdowns of renewable energy systems (more about this in our article: Why around 3% of all renewables are shut down annually) and the discourse on security of supply.

In this public discourse, the question is often asked to what extent the energy supply is ensured when the wind is not blowing or the sun is not shining. On the other hand, however, there will be a great many times when there will be significant flows from these forms of production. The storage of energy is increasingly recognized as a decisive element for integrating renewable energy into electricity systems and for extensive decarbonization. As part of congestion management, battery storage systems can be used in a targeted manner to avoid overloading the nationwide power grid. Like other generation plants, they are available to transmission system operators for redispatch measures. By strategically placing them at network nodes where network bottlenecks occur particularly frequently, battery storage systems can even contribute particularly effectively to preventing bottlenecks. In addition to normal redispatch measures, i.e. throttling the power of the large battery storage devices, the memories can also optionally act as consumers and thus further increase their positive effect. Large-scale battery storage systems can not only be throttled to zero like generation plants before bottlenecks, but can also be used to collect and store excess capacity in the grid that would otherwise be lost unused. By storing excess energy, they can balance out volatilities and at the same time integrate more renewable energy into the power grids. Once the bottleneck is avoided, the storage systems can feed this electricity back into the grid with a time delay. This is particularly useful at times of high demand, when generation from renewables is low and conventional power plants would have to be used to cover the load. The additional share ofCO2 -low power, which can be provided by the battery storage systems during these periods, then displaces theCO2 -intensive power plants and thus accelerates the achievement of decarbonization goals. By improving the integration of renewable energies, creating flexibilities in the power grid and, as a result, the increasing crowding out of conventional power plants, battery storage systems make a decisive contribution to decarbonizing the power supply.

Expanding renewables lowers C02 intensity of the power mix is enormous

Looking atCO2-The intensity of the German electricity mix makes it clear what effect battery storage has on CO savings2 Can have. This shows how many greenhouse gas emissions are inCO2 -equivalents are emitted per kilowatt hour of electricity produced. According to the Federal Environment Agency, there were average greenhouse gas emissions of 438g CO in 20202 per kWh of electricity produced, in 2021 it was even 485 g/kWh (including pre-chain emissions).
Comparing the emissions of individual energy sources reveals major differences. This is because the production of renewable electricity produces on average only 10% of the greenhouse gases that fossil energy sources would cause.

Looking at an exemplary daily course ofCO2 -Emission factor illustrates this.

In the early morning hours or even late in the evening, CO reaches2 -Emission factor its peak times. Due to the volatility of renewable energies, conventional energy sources must increasingly be used to supply electricity. On this example day, up to 580 g of CO are produced2 electricity emitted per kilowatt hour. However, with increasing solar output, especially around lunchtime, i.e. between 11 a.m. and 2 p.m., there is a rapid decline in greenhouse emissions to just under 310g/kWh. During this time, low-greenhouse gas renewable energies are increasingly displacing fossil producers and thus reducing CO emissions2 hugely. Overall, on this exemplary course of the day,CO2 emissions are reduced by 270g/kWh at peak times. The positive contribution of renewable energy is clearly visible. If, as a result of the expansion of battery storage systems, even more electricity from renewable energy sources is integrated into the electricity mix and correspondingly displaces more conventional power plants, CO will also fall2 emissions in Germany.


Mastering the energy revolution in Germany and decarbonizing our power supply requires a fundamental restructuring of the energy supply and, above all, a massive expansion of renewables. After all, switching from fossil fuels to sustainable energy sources could save up to 90% of greenhouse gas emissions in the energy sector. At the same time, the requirements for our power supply are also changing as a result of a switch. Battery storage systems are a crucial component for decarbonizing energy supply. By offsetting volatilities and storing surplus electricity, they can integrate more renewable energies into the power grids overall. At the same time, they add CO to the grid by shiftingCO2 -low electricity also more clean electricity available. As a result,CO2 -increasingly displaced or replaced intensive power plants and avoided enormous amounts of greenhouse gases. In order to achieve climate neutrality in the German energy industry by 2035, many structures must change rapidly in the coming years. For example, the Federal Network Agency has also made adjustments and increased forecasts within its scenario framework for the 2037/2045 Network Development Plan. The demand for large battery storage was increased 14-fold to 54.5 GW by 2045. The Fraunhofer Institute ISE is even predicting a demand for 104GWh by 2030, with an increasing trend. It is clear that battery storage systems play a decisive role in decarbonization.

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