Sector Coupling: The Next Step in the Green Energy Transition (“Energiewende”)

Viable concepts of the future necessitate a holistic approach to energy markets

Although many are unaware of this, in Germany the energy system transition to alternative energy sources “Energiewende” began as a solution to climate issues more than 30 years ago. For 20 of those years, Steinbeis Professor Dr. Zbigniew Antoni Styczynski has been working on this topic alongside, among others, his former professorial chair at Otto von Guericke University Magdeburg. The issue of climate change is returning with a vengeance to social and political debate and, says Styczynski, it’s high time to initiate a phase of “sector coupling.”

Prosperity index versus annual energy consumption per capita. Source: BP 2019


The energy transition extends over several phases, the last of which should lead to the complete replacement of fossil fuels. In Germany, options will therefore need to be found to answer increased demand for electricity and chemical energy carriers – green hydrogen – through imports from countries offering greater potential to generate wind and solar energy. By the time this phase finishes, the task of transforming energy provision – as an overall energy supply system – should also be completed.

The projected time needed for the energy transition – roughly 80 years – is comparable to the time it took to build the electricity supply system, which started with the first, simple systems in the 1880s and neared completion with the advanced systems introduced in the 1960s. This once again highlights the significance of current endeavors.

The current discussion in society is entirely necessary, and it is important that the energy transition is seen as a global challenge. In other words, all countries will have to pull in the same direction, even if their starting positions could scarcely be more divergent. In many countries, there are simply not sufficiently high living standards to even start thinking about the energy transition. The Human Development Index (HDI), a benchmark system widely used to gauge achievements in key areas, is based on three groups of indicators: life expectancy, education, and gross domestic product (GDP). These are broken down specifically into life expectancy at birth, adult literacy, mean years of schooling, and GDP per capita. The index is published along with a variety of additional economic, social, and political data in the annual reports of the United Nations Development Programme.

High levels of energy consumption do not equate to prosperity

“If you compare the HDI with energy consumption per capita, you see a direct correlation between the two values: High energy consumption – up to about 100 GJ per capita per year – is already linked to high HDI levels, but further rises in per capita energy consumption don’t necessarily equate to an increase in HDI,” explains Styczynski. For example, at 0.94 the HDI for Germany (maximum value 1.0) is significantly better than that for Saudi Arabia (0.83). But despite this, Saudi Arabia has more than twice the per capita energy consumption of Germany. Nevertheless, the countries with energy consumption levels below 100 GJ per capita are home to the vast majority of the global population. “That’s why it’s particularly important to push ahead with the green energy transition in the industrialized nations. After massive expansions in renewable energy generation, it’s time to initiate a phase of sector coupling,” asserts Styczynski.

The role of sector coupling in broadening horizons

Sector coupling is basically shorthand for the many things that need to happen throughout the economy in the coming years to make everything sustainable and resilient. As such, it points to the networking of different sectors of the energy industry based on the shared goal of slashing fossil fuel use. Now that the term “Energiewende” has become established as the German buzzword for “generating energy from renewables,” sector coupling can be understood as extending and transferring this concept to the entire energy industry.

As far as generating electricity is concerned, there can be no doubting that it is possible to base systems exclusively on renewable energy sources. There are already numerous examples showing that by cleverly managing electricity grids, it is possible to integrate renewables 100% into systems, without compromising grid stability and the reliability of electricity supplies. Given plans to phase out nuclear power by 2022 and the decision to phase out coal-fired power generation by 2035 at the latest, it is therefore time to think about all sectors of the energy market, and not just electricity. How will they operate if 100% of energy is supplied as renewable electricity? Or perhaps more importantly, is that even possible? Which other sources of primary energy will be needed to sustain advanced human travel and industrial infrastructures? To answer these and other questions, systematic studies are needed.

There are a large number of national research institutions that have already been conducting such studies for some time, including the German Academy of Science and Engineering (acatech) and the German Energy Agency (Dena). The German Association of Energy and Water Industries (BDEW) and international organizations such as Cigré (Conseil International des Grands Réseaux Électriques) and the European Network of Transmission System Operators for Electricity (ENTSO-E) focus on different points in their assessments, but clearly point to promising times ahead under a sustainable system. The studies also use mathematical modeling to validate the plausibility of their findings.

The green energy transition requires specialists

“One thing we’ve noticed in recent years is that many approaches to the energy transition are pretty much oven-ready right now, such as electric vehicles, but others, like the hydrogen economy, still require a lot of time and effort. Engineers and other specialists will be needed in these new areas, and in turn this will require new training formats and completely new degree disciplines,” says Styczynski, highlighting another aspect of the energy transition. For example, for many years training to work at power plants revolved heavily around the fundamentals of coal power generation and nuclear power plants. These days, such topics are only looked at briefly from a historical perspective. Instruction now focuses on systems powered by wind, photovoltaics, and biogas. To keep up the momentum of this development, Styczynski and his Steinbeis Enterprise, Power Systems and Renewable Energy Resources (ENRE), have devoted the past five years to training the next generation of specialists, also working alongside project partners on a number of specialist publications on the issues faced during the energy transition.

Zbigniew Antoni Styczynski is the author of several specialist books on the energy system transition (published by Springer Verlag). His most recent publication, part of a series on “Energy in Science, Technology, the Economy and Society,” is titled (German Edition 2021, English Edition announced for 2022):

Sector Coupling – The Energy-Sustainable Economy of the Future.

In this book, Styczynski & coauthors outline technical approaches and examine the debate currently witnessed in society from a technical standpoint with the aim of fostering a deeper understanding of the topic, not only among students but also in society in general.


Prof. Dr. Zbigniew Antoni Styczynski (author)
Steinbeis Entrepreneur
Power Systems and Renewable Energy Resources (Remseck am Neckar)