Technical Article

Interview: Prof. Dr. Bruno Burger, Fraunhofer ISE - Current developments and challenges of the energy transition

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We at Kyon Energy had the opportunity in an interview with Mr. Professor Bruno Burger to talk about the current developments and challenges of the energy transition. He is a senior scientist at the Fraunhofer Institute for Solar Energy Systems (ISE), energy expert and initiator of Energy Charts.

Kyon Energy: What is the current annual demand for electrical energy in Germany and how has it changed in recent years?
Prof. Dr. Bruno Burger: In 2022, we had a gross electricity consumption of 550 TWh. The table below shows changes in consumption over the last thirty years.

Where do you think it will develop over the next few years - especially as the electrification of the heating and mobility sector progresses?‍

Sector coupling will increase electricity consumption, partly because we electrify sectors such as transport and heating. Electricity generation must also increase accordingly. Fraunhofer ISE predicts that almost 1,400 TWh of electricity will be in use by 2045 (see figure).

By 2030, Germany has set itself the goal of obtaining 80% of its electricity consumption from renewable energy sources and gradually shutting down power plants with non-renewable primary energy sources. The share of renewables is currently around 50%. Do you see the government's objective as realistic?
Federal Government's goals are realistic and are also very consistent with our calculations.

How do you rate the current progress of the energy transition?
After losing almost 10 years due to the electricity price brake from Ministers Altmaier and Rösler, we have a lot of catching up to do. The current government is doing everything it can to ensure that the energy transition progresses as quickly as possible. Many steps have already been set for this in 2022. 2023 must now show that the goals are achievable. The expansion of renewable energies is likely to progress faster than the expansion of networks.

In your opinion, what are the biggest challenges that this necessary conversion of the electricity infrastructure must overcome?
The biggest challenge is not technology. We've already come a long way there. I see the challenge in involving the entire population in the energy transition and motivating them to do so. The current dispute in politics shows that the population and also politicians are sometimes no longer able to keep up with the planned pace.

How can the integration of renewable energy into the existing power grid be improved?
We need more power lines from north to south. Unfortunately, Bavaria had blocked this expansion for a long time. But now we need to move forward. In the grid, we need short-term storage (battery storage) in order to be able to store the midday peak of solar power generation. In addition, more data and measurement values are required to optimize network operation. For times with high shares of renewable energy but low transport capacities, we also need a way to limit electricity flows abroad.

In your opinion, what needs to change so that we can master the energy revolution?
We need a clear commitment from all parties to the energy transition. The constant discussions about imports of hydrogen and e-fuels are paralyzing us and keeping us from working.

In recent weeks, the Federal Government has once again focused more on expanding renewables and wants to press ahead with this more intensively. How much installed PV and wind power do we need in Germany to reach the 80% target?
The federal government wants 215 GW solar, 115 GW wind onshore and 30 GW wind offshore installed by 2030. This is in line very well with our calculations.

What expansion rates do we have to meet annually for this?
The expansion rates of solar energy are being increased to 22 gigawatts (GW) per year. The output of onshore wind energy is expected to increase by up to 10 GW per year. (BMWK)

A lot of electricity from renewable power plants is already being curbed today, as the grids are unable to absorb locally. In addition, above a certain installed PV and wind capacity, there will be more and more times when renewable electricity covers the entire load in Germany. What role do you attribute to battery storage systems here?
Battery storage systems are very important for the short term balance between generation and consumption. That is why we must significantly expand it by 2030.

In your estimation, what storage capacity is necessary to be able to achieve the 80% target? (Based on stationary large storage systems)According to our calculations, we need 250 GWh of battery storage by 2030. Of these, around 150 GWh are mobile batteries and around 100 GWh are stationary batteries.

What measures should politics and industry take to further promote the expansion of renewable energy and the use of battery storage systems?
For now, all hurdles that have been built up over the last ten years must be dismantled again. This process is already going very well. The governing political parties must make a clear commitment to renewable energies and not repeatedly steer the discussion towards old technologies (nuclear energy, combustion engines) or new technologies that are not yet available (SMR, nuclear fusion). These discussions cost a lot of energy, unsettle citizens and slow down the energy revolution.

There is a lot of talk in politics about the use of "green hydrogen." This is to be produced with electrolysis plants and later converted back into electricity using fuel cells or in gas turbines. What do you think of this approach? Is implementation by 2030 realistic?
According to our calculations, we must focus on expanding wind, solar, batteries and grids by 2030. Only then will we have sufficient surpluses for electrolysis to produce renewable (green) hydrogen. However, we will first use this as an important raw material in industry. Only from around 2040 will we have enough hydrogen for reconversion into electricity. By the way, I don't participate in the color theory of hydrogen. It is only used for concealment. Green hydrogen is renewable hydrogen and blue hydrogen is fossil hydrogen. The color blue absolutely does not match the fossil origin of the natural gas from which hydrogen is to be produced.

From our point of view, the efficiencies for this type of electricity storage are too poor to temporarily store short-term generation peaks and return them to the grid a few hours later. We are therefore of the opinion that greater flexibility of the load and more highly efficient short-term storage systems are necessary. What do you think of this topic?
Yes, we agree. Short-term storage systems are important first. They store solar power for us from noon into the evening hours and wind power from the night for the morning hours. At the moment, the increase in battery storage is increasing very quickly. If things continue at this rate, the capacity of the battery storage systems will be greater than the output of the pumped storage systems in just two years.

What role does the research and development work of the Fraunhofer Institute ISE play in implementing the energy transition and what projects are you currently carrying out?
Fraunhofer ISE is working on many different technologies for the energy transition, including the development of solar cells and solar modules, inverters, charging infrastructure for electric cars, control and control technology, power grids, heating concepts and heat pumps, building technology, solar thermal power plants, battery technologies, fuel cells and electrolysis, system simulations, and much more. We also support industry in decarbonization, both in heat and in the electricity sector.

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