“Energy-efficient companies will be more independent.”

“Energy-efficient companies will be more independent.”
Marginal Column
Prof. Dr. Alexander Sauer

Prof. Dr. Alexander Sauer
has been Head of the Institute for Energy Efficiency in Production (EEP) of the University of Stuttgart since 2015. Until 2006, he was Head of Department at the Aachen-based Laboratory for Machine Tools and Management (WZL) and managed the competence center Aachener Werkzeug und Formenbau. Professor Sauer then moved to an automotive supplier, where as a member of the Executive Board, he was responsible for the areas of production planning, logistics, maintenance and production worldwide. From 2011 to 2015, he was head of the applied manufacturing technology laboratory at the University of Applied Sciences Munich.

Copyright Photo: Prof. Dr. Alexander Sauer


November 2016


In this interview, Professor Alexander Sauer, Head of the Institute for Energy Efficiency in Production (EEP) at the University of Stuttgart, talks about energy-efficient production and explains how Industry 4.0 and smart grids can make factories more efficient in the future.

Professor Sauer, what does “energy efficiency in production” actually mean?

Efficiency is usually defined as the cost-benefit ratio. The smaller the quotient, the greater the efficiency. If I want to determine the energy efficiency in a factory, I first need to decide on the scope of the balance sheet: Will I be looking at a process, a line, or the entire factory? I then choose the evaluation parameter for the costs. The kilowatt-hour is of course the obvious choice, but we can also use a ton of CO2 or something else. By switching to a different energy company, it is possible to reduce costs or improve the CO2 balance without changing the amount of energy needed as measured in kilowatt-hours.

How does the scope of the balance sheet impact the possibilities to increase the efficiency?

If I apply the balance sheet to a manufacturing process that needs only electricity, the only way to be more efficient is to reduce the amount of electricity needed for each manufactured component. However, if I consider the factory as a whole, then the waste heat could be used for other processes, for example. Although I would not improve efficiency for that specific process, I would, however, reduce the energy requirements of the factory as a whole. In many cases, this is the recommended approach.

From your perspective, what role does energy efficiency play for industrial companies today?

Energy-intensive businesses have long been deeply involved with this issue. For companies with lower or medium energy consumption, it is often not a high priority. They usually only tend to have one or just a few gas or electricity meters and the consumption is not accurately documented. A detailed analysis of the actual consumption is the first step to improving energy efficiency. More and more companies will undertake this step in the near future.

How can Industry 4.0 help to improve energy efficiency in production in the future?

The better the individual manufacturing components are networked to each other, the easier it will be to coordinate them. In one project, we looked at when it is worthwhile for machine tools in Industry-4.0 production to go into stand-by mode and the warm-up phase was also taken into account. If such parameters are explored, new energy efficiency potential can be realized in networked manufacturing. Batches can thus be produced automatically so that a machine can be in operation for a certain time and then turn off, instead of working sporadically and remaining in operation the entire time.

How can energy efficiency already be taken into account when planning a new production facility?

Energy and utilities have always played a major role in energy-intensive companies in the basic chemicals, steel and glass industries. However, at most production facilities it’s more about logistics models when it comes to digital factory planning. In addition to this, a plan of the factory as an energy system must exist in future in order to take advantage of the cross-process energy efficiency potential. Ideally, this not only protects the environment, but also helps reduce energy costs. Relating to factory planning, the question currently being asked is whether it would not make sense to equip parts of the factory with DC instead of AC networks. The implementation is still a thing of the future, however it could provide benefits: Production facilities could manage with less power electronics and could process DC directly from photovoltaic systems or batteries that store recovered electricity. We are working intensively on this concept at EEP.

What role are smart grids, which are also finding their way into manufacturing, going to play in the future?

The idea of smart grids in production is to be able to specifically control energy requirements. Today, it is already in the interests of industrial enterprises to generate as few power fluctuations as possible. As soon as a company can actively level out its energy consumption, it can increase or decrease it in certain areas as needed. From heat storage to the activation of alternative energy sources, there are many ways to control energy requirements. In the future, this will help in two ways: In countries with a high proportion of volatile, renewable energy sources, factories will be able to respond better to over and undercapacities in the network. In regions with a more traditional energy grid, smart grids help to overcome power failures by enabling the factory to run for a while at a lower energy level and with its own energy sources such as a thermal power station.

In your opinion, what will be the main driving forces behind energy efficiency in the future?

On the one hand, there are the cost advantages, which can lie in the double-digit percentage range of energy costs, particularly when a company has not made much progress in this area to date. On the other hand, customers in the future will also be interested to learn how much energy was used to produce a certain product. The main driving forces, in my opinion, will definitely be social pressure and legal requirements. To achieve the emission targets agreed at the UN Climate Change Conference in Paris, it is not enough to focus solely on energy production. The legal requirements can only be met with a massive increase in energy efficiency. I therefore expect more regulations here in the coming years. One thing is certain: Energy prices are becoming more volatile. Energy-efficient companies will be much less affected by these price fluctuations and, as such, will be more independent. With industrial smart grids, companies can even use such fluctuations to their advantage.