Fraunhofer | People in research 2022 - Prof. Dr.-Ing. Bruno Burger

“We have to leave the age of fossil fuels behind us once and for all and move to renewable energy supplies. There is no alternative.”

Prof. Dr.-Ing. Bruno Burger


Doctor of engineering 

Senior Scientist in the Power Electronics, Grids and Smart Systems section at the Fraunhofer Institute for Solar Energy Systems ISE in Freiburg

Honorary professor at the Institute of Electrical Engineering of the Karlsruhe Institute of Technology (KIT)

Making the most of the sun’s power

The scene is Germany, in fall 2022: Gas and electricity prices are skyrocketing, and the German federal government has declared a gas crisis and called on companies, institutions and citizens to adopt energy-saving measures. It was not until the start of 2023 that the German Federal Network Agency and the Federal Ministry for Economic Affairs and Climate Action (BMWK) sounded the all-clear: a severe gas shortage was no longer to be expected for winter 2022/23.

The 2022 energy crisis made Prof. Bruno Burger one of the most “in-demand” scientists at Fraunhofer. The “energy researcher,” as the media like to call him, developed the Energy-Charts platform to answer questions such as: What energy sources are used to produce electricity? What does electricity cost at specific times? How much electricity are we importing or exporting? The Energy-Charts track electricity generation data across Europe in real time, based on data sources such as the European Energy Exchange (EEX) in Leipzig and the European Power Exchange EPEX SPOT in Paris, which update their figures hourly. Everyone was looking to Prof. Burger’s Energy- Charts for information — from Germany’s Tagesschau news program and the Deutschlandfunk radio station through to YouTube channels and broadcaster ARD’s business magazine Plusminus.

Prof. Burger has dedicated the last 40 years of his life to renewable energy. Even in his university days back in 1988, he made his student apartment independent from conventional electricity suppliers by installing two solar modules, and built an inverter and a standalone power solution for the room he rented. He and the other three aspiring electrical engineers that shared his apartment looked on in awe as the electricity meter began to run backwards and they started to feed power into the grid. For his thesis on the world’s first transformerless inverter, Prof. Burger traveled back and forth by train and folding bike between the Karlsruhe Institute of Technology (KIT) and Fraunhofer ISE in Freiburg, lugging his instruments and equipment along with him. As part of his doctorate, he built a standalone power supply solution for the Höhengasthaus Teufelsmühle guest house in the Black Forest. Prof. Burger’s first job was at the Institut für Solare Energieversorgungstechnik ISET (institute for solar energy supply technology), which was affiliated with the University of Kassel and has since become the Fraunhofer Institute for Energy Economics and Energy System Technology IEE. He spent his time there working with the company SMA to develop the Sunny Island inverter — a device which is still in production today.

In 2001, Prof. Burger joined Fraunhofer ISE, which is where he started building the Energy- Charts data portal in 2010. His goal was to create a source of transparent, up-to-date and objective information on the energy transition. As the annual evaluation for 2022 showed, the portion of renewable energy in net electricity generation figures, i.e., the electricity mix that actually comes from a power outlet, reached 49.6 percent last year. Wind energy was the biggest electricity generator in 2022, followed by brown coal, solar power, black coal, natural gas, biomass, nuclear energy and hydrogen. The share of wind and solar power increased significantly. Nevertheless, it was only photovoltaics, which experienced an expansion that the sector had not seen since 2013 and increased its contribution to electricity generation by 19 percent, that reached the expansion goals the German federal government had set for renewable energy.

“Everyone has a part to play in the energytransition,” insists Prof. Burger. He and the around 1,400 other employees at Fraunhofer ISE are not giving up on their mission to push solar power’s potential right to its limits, as this source of energy is currently the cheapest way of generating electricity in many parts of the world.

More information


Net Electricity Generation in Germany in 2022

Significant increase in generation from wind and PV



The data platform of the Fraunhofer Institute for Solar Energy Systems ISE is the most comprehensive database for power generation in Germany. The Energy-Charts provide interactive graphics on: electricity production, power generation, emissions, climate data, spot market prices, energy transition...