Pictures of the Future    Spring 2006

Energy Misers

Worldwide, there are approximately 20 million industrial motors—with vast potential for saving energy. Siemens is developing solutions to protect the environment and reduce costs.

They move escalators and ventilators, trains and paper machines. Without electric motors, our high-tech world would stand still. But all of this takes a lot of electricity. In 2004, industrial electricity consumption in Europe alone was around 950 TWh—which is approximately equivalent to the output of 400 fossil-fueled generating units with a carbon dioxide output (CO₂) of 418 mill. t. Drive technology accounts for two-thirds of this amount.

Rising energy prices are forcing industry to optimize processes, while concerns about the environment are reflected in a growing determination to meet the obligations of the Kyoto Protocol. Between 2008 and 2012, the EU intends to reduce CO₂ emissions by 8 % (as compared to 1990). That means that when it comes to electric drive technology, emissions should be reduced from 270 mill. t (in 2000) to 240 million by 2010. The EU member countries must implement these EU guidelines in national laws by 2007.

The potential is there—"especially for auxiliary processes that do not serve production directly," explains Dr. Peter Zwanziger, who focuses on the topic of saving energy at Siemens Automation and Drives (A&D). "Such processes include, for example, the preparation and transport of auxiliary materials, air conditioning and waste removal." The largest industrial consumers are compressors, conveyor belts, and mixing and milling systems, as well as pumps for heating, ventilation and air conditioning. In the paper industry, for example, a medium-sized operation will have more than 3,000 motors running 24/7.

Quick Amortization. The technology for saving already exists. According to the German umbrella organization for the electrical industry, frequency converters alone account for about 90 % of the energy savings potential. The rest can be achieved with energy-saving motors. However, high acquisition costs frighten off many managers—which is a paradox, given a service life of ten years. After all, when you have 2,000 hours of operation annually, the purchase price accounts for less than 3 % of total costs. Energy costs, by contrast, account for over 95 %.

Decision-makers at Volkswagen have understood this fact. For over two years now, they have consistently been replacing defective standard motors with Siemens motors of the highest efficiency class (EFF1). "Energy costs accumulated over a motor’s service life far outweigh the price of the motor itself," reports André Prätzel of VW Plant Service. Even with low industrial energy prices, the additional costs of a high-efficiency motor are amortized after 12 to 18 months (see box), which explains why VW is using only EFF1 motors for newly installed systems.

The latest generation of energy-saving motors from Siemens A&D can reduce power loss—the power converted into heat—by up to 45 % as compared to conventional electric motors. For a 1.1 kW motor, that increases its efficiency from 77 to 84 %. A&D achieves this by paying plenty of attention to the ventilation, housing and motor winding. This includes a higher percentage of active materials, such as aluminum, copper and electric sheets.

"We’re working on optimizing the winding system by using a modified manufacturing process," explains A&D Product Manager Fred Hochbrückner. "The armature—that is, the rotating part of the motor—also offers savings potential. Here copper instead of aluminum is a very promising material because it has a lower loss resistance. Thus we can build motors more compactly with the same output. We are nearly ready for mass production," he says. In addition, an improved ventilation system dissipates more heat. The lower thermal load increases the life span of the motor, and the lubricant remains effective longer. This is an important aspect for customers. Less maintenance is needed, and the system enjoys more up-time.

"The exchange of drive components and the use of frequency converters are important. But systematic energy optimization produces even better results," says Michael Schweinle of Siemens Industrial Solutions and Services (I&S). With this in mind, I&S offers a three-level concept for optimizing existing systems that ranges from the calculation of the theoretical savings potential and energy analysis to the optimization concept and its implementation. "The costs, including motors and frequency converters, are amortized by the energy savings after 24 months at most," explains Schweinle, referring to a pilot project at a box manufacturer.

But costs aren’t the only element in the foreground. "For Siemens, CO₂ reduction is part of its social responsibility," says A&D expert Zwanziger. That’s why the company is a partner in the EU’s voluntary Motor Challenge Program. Participating companies are obligated to save energy or to actively support increased energy consciousness and promote highly efficient technologies. A&D and I&S have committed themselves to an action plan for energy-saving solutions and agreed on it with the EU Commission. Everybody will profit: the drive operators, the drive technology manufacturers, and ultimately the environment and the people.
                                                                                                       Evdoxia Tsakiridou