Renewable energies: Now it's all about energy storage systems

Research in the field of energy storage is of great importance – great market development potential – opportunities for post-EEG systems

The market for renewable energies is growing. Global investment in renewable energy has almost doubled in the last decade. While we are experiencing the biggest boom worldwide, in Germany they are declining, except for photovoltaics. In 2019, around 11 billion euros were invested in Germany. The focus of these investments was in the area of ​​solar energy.

The market for photovoltaics in Germany has been developing upwards again since 2014.

Global investments in wind energy technologies amounted to around $143 billion in 2019. Investments in solar energy technology were recently at $141 billion.

Even if the number of renewable energies in Germany is currently declining, it should not be overlooked that Germany is the country in the world with the highest share (52%) of renewable energies in relation to fossil energy sources.

With 224 terawatt hours, Germany ranks third after China and the USA in the consumption and provision of renewable energy. And that's ahead of India and Brazil, which are much larger in terms of population and area.

For November 2020, Germany generated 54% of electricity from renewable sources. The annual average from December 2019 to November 2020 was 52.46%.

However, this is not a constant performance. The fluctuations range from November 2019 at 37% to the high of 61.7% in February 2020. This problem will become even worse in the near future with the further expansion of renewable energies.

With renewable energies, the national power grid is also changing. While power grids with central power generation have dominated so far, the trend is towards decentralized generation systems. This applies to production from renewable sources such as photovoltaic systems, solar thermal power plants, wind turbines and biogas plants.

“Electricity generation from solar and wind energy systems makes the supply system much more fragmented and weather-dependent than the operation of conventional power plants,” says Prof. Dr. Clemens Hoffmann, head of Fraunhofer IEE.

Suitable for:

• Artificial intelligence in the field of renewable energies

This leads to a much more complex structure, primarily in the area of ​​load control, voltage maintenance in the distribution network and maintaining network stability. In contrast to medium-sized to larger power plants, smaller, decentralized generation systems also feed directly into the lower voltage levels such as the low-voltage network or the medium-voltage network.

Due to the larger share of renewable energies, it becomes more important to align the fluctuations in energy production with the fluctuations in energy consumption by balancing them with energy storage systems.

Therefore, the possibility of storing electrical energy using energy storage or storage power plants will play an important role in the next few years.

In 2018, the capacity of energy storage was around 17 gigawatt hours. According to an estimate by Bloomberg New Energy Finance (bnef.com), the capacity will be over 2,800 GWh in around 20 years.

Large battery storage systems are already being used in Germany to stabilize the grid. In 2017 the capacity was around 250 megawatt hours.

In comparison, the capacity of home battery storage in Germany was 545 megawatt hours in 2017.

In order to successfully shape the energy transition, research in the field of energy storage is of great importance. The faster it is possible to store energy efficiently, the sooner fluctuations in the power grid can be balanced out and fossil fuels can be moved away from. In 2019, the federal government provided funding for electrochemical storage worth around nine million euros.

Suitable for:

• Who is driving investments in renewable energies?

While the market for solar modules is already highly competitive and you look at the capacity requirements of energy storage systems, you quickly notice that there is still a lot of market development potential here.

Only storage facilities that are eligible for KfW funding are taken into account here. Manufacturers whose storage systems are not eligible for KfW funding are not listed here. In 2017, SMA's share of the solar power storage market in Germany was around six percent. Sonnenbatterie: The company has been operating as Sonnen GmbH since November 2015.

According to a forecast, around 100,000 photovoltaic systems with solar power storage were installed in Germany in 2018. The number of systems installed is increasing significantly every year - in 2013, 5,000 solar power storage units were counted in this country.

Suitable for:

• Energy storage – Interesting figures, data and facts can be downloaded as a PDF at the end of this article

In an interview with Focus Online, Oliver Koch, CEO of Sonnen GmbH, describes the networking of batteries and the virtual power plant as the clean and decentralized energy system: “Households are replacing power plants and electricity is produced decentrally.” According to Mr. Koch, a zero-euro electricity bill is possible.

Mr. Koch recommends that plant operators for whom EEG funding will soon end should recalculate the matter and consider using the electricity they produce themselves in the future.

We also suggested this option in September: What to do? Funding for old photovoltaic systems is expiring

The Stadtwerke Tübingen shows that there is another way: They are offering operators of post-EEG systems six cents per kilowatt hour from 2021. Lechwerke AG recommends making technical adjustments to the solar system and consuming the solar power yourself in the future. With the right storage solution, the solar system should become even more efficient.

However, it is still unclear where the journey is headed. The draft amendment to the EEG contains an important change for post-EEG systems: a temporary exception for small PV systems with full feed-in is planned. There should be a transitional regulation for systems with an output of up to 100 kWp, which are allowed to continue feeding in their electricity until 2027. However, all of the electricity must be fed in. Own consumption is excluded.