In the operation of electrical drive systems there is enormous potential for savings. With efficient motors, suitable converters, and modern IIoT applications, considerable savings can be achieved in terms of CO2 emissions, the use of resources, and lifecycle costs. Nevertheless, around 80% of the energy consumption in today’s existing systems is from medium-sized electric motors, the energy efficiency of which usually fail to meet current standards, and which are often completely oversized for the respective application. As the cost of energy consumption for a motor over its entire service life add up to 97% of the total costs, the desire for the most efficient solutions possible is as much a matter of economic reason as ecological responsibility.
Electric drives are ubiquitous, especially in industry and building technology, for example in pumps, compressors and air conditioning systems, in cranes, elevators, and conveyor belts. Industry accounts for over a third of the world’s electrical energy consumption, and around 70% of this is due to electrical drives. Buildings account for around 30% of the world’s electrical energy requirements, of which 38% are used to operate electric motors. And demand is increasing: forecasts predict that today’s global economic output will double by 2050. As a result, the demand for electric drive systems continues to rise significantly – and at the same time enables great savings potential through efficient and intelligent system solutions even for the simple drive-train. The most recent studies assume that on average, up to 30% energy costs can be saved when both purchasing and operating new electric drives.
Siemens is meeting its responsibility for greater energy efficiency by continuously improving its products and system solutions – with the clear goal of using less energy and so generating fewer CO2 emissions.
Hand in hand: climate protection and economic growth
With the Paris Climate Protection Agreement, 196 countries committed to limit global warming to well below 2°C. At the same time, megatrends such as urbanization, mobility, and automation are increasing mankind’s energy needs. Therefore, regulations to increase energy efficiency now play a central role in the implementation of the Paris Agreement. Worldwide, regulations are in force in the EU, China, and the USA, among others, which specifically focus on the great potential of efficient technologies for electric motors. In the EU alone, new ErP directives provide for a savings target of 40 million tons of CO2 by 2030 through the mandatory use of efficient technologies. China has set itself the goal of reducing its energy consumption cumulatively by 13.5% and CO2 emissions by 18% relative to gross national product by 2025.
Around 75% of the existing electric motors are currently installed in pump, fan, and compressor systems, which largely correspond to old efficiency standards such as IE1 or IE2. Regulations are being passed worldwide that now provide for a minimum efficiency class of IE3 for new systems. A look at the current Siemens motor portfolio shows, however, that the next efficiency class IE4 (‘Super Premium Efficiency’) is technically already widely available and in use. This enables a further noticeable reduction in motor losses compared to the intended legal IE3 standard. Depending on the upgrade scenario, energy efficiency potential of up to 6% can be achieved on average just by simply replacing the motor. The potential of regulated drives compared to unregulated fixed-speed uses is in many cases much higher. Depending on the application, up to 30% can be shaved off and high efficiency gains can be achieved even with low load fluctuations.
The key to greater energy efficiency lies in the overall system
Even if these individual measures can achieve significant positive effects, optimizing the overall system across all areas naturally offers the highest potential. By integrating the measures mentioned – increase in engine efficiency, use of variable-speed control, an overall system view based on modern digital system components and tools, plus use of electrically-buffered energy in the motor network – savings of up to 60% can be achieved on average.
There is potential for savings of up to 60% in the entire drive system thanks to energy-efficient components and optimization solutions
The networked system approach and the consistent analysis of system data represent the greatest impact on raising energy efficiency to a truly sustainable level. This goes hand in hand with considerable savings in CO2 emissions, the use of resources, and a serious reduction in lifecycle costs. Investments in more efficiency and productivity go together with greater ecological and economic sustainability.
In line with this system concept, the Siemens portfolio with efficient SIMOTICS motors, high-performance SINAMICS converters and perfectly matched digitization solutions is also geared towards optimizing the overall energy efficiency of new systems. And existing applications can also be designed to be energy efficient with limited effort using appropriate retrofit solutions.
Perfect match: the right drive-train for every application
Modern frequency converters and highly efficient motors can save up to 30% energy in typical industrial applications such as pumps, fans, or compressors compared to unregulated old systems. As shown in the following example, this value can be increased to 45% by including the drive-train, here a pump. The converter ensures that the drive system runs energy-efficiently even in partial load operation by adapting the speed and torque to the load requirements of the respective system. This means that no more than the required performance for the specific application is ever called up.
Most existing systems installed today for pumps generally correspond to efficiency class IE1 or IE2. The performance of these motors is usually regulated by throttling, which produces a high level of waste heat and so high energy losses. In many countries, such systems will soon no longer achieve approval. This is easy to understand, as using a converter-controlled synchronous reluctance motor according to the IE4 standard can achieve energy savings of over 46% and 62 t CO2 per year, as the following example calculation shows.
Example calculation with Siemens SinaSave: otor of efficiency class IE2 with throttle control compared to a synchronous reluctance machine (IE4) and SINAMICS G120 converter:
The speed-controlled IE4 drive achieves savings of up to 98 MWh and 62 t CO2 per year compared to the existing system
Good connection: digital process optimization
The more specific and diverse the applications and components become, the more complex the overall system can become. Therefore, especially in an industrial environment, approaches are needed that take the system with its interactions and synergy effects into account in detail and always optimally align it. The basis for this is provided by intelligent sensors and analysis tools that monitor, harmonize, and improve all process flows as part of a higher-level system approach. Smart sensors such as SIMOTICS CONNECT 400 enable the analysis of the connected electric motors at the motor level for the first time. Modern converters usually do not need any additional external sensors at all, as they are either equipped accordingly themselves or can directly evaluate and forward specific system parameters. At the digitization level, suitable tools such as SIDRIVE IQ Fleet or Analyze MyDrives then enable the data obtained to be evaluated, including visualizations, simulations, and recommendations for action.
Already in the planning phase, incorrect planning and oversizing can be identified through virtual simulations of the components in the drive-train. During operation, the connectivity enables the operating data to be read out and analyzed using cloud- and industrial-edge-applications. In production, digitization solutions in the drive-train help with the early detection of product problems and the avoidance of consequential errors. Indirect effects that are not related to the drive can also be identified via the data acquisition of the drive components. In this way, the entire operation in the network system can be continuously optimized – in an uncomplicated way and without expert knowledge.
Digital tools offer options for reducing CO2 emissions throughout the drive-train – while reducing life cycle costs at the same time
Evaluations during operation show that the use of intelligent sensors and data analysis applications in complex processes can save up to 10% process energy. With the help of Predictive Maintenance Services, i.e. applications for predictive maintenance, it has been possible to increase the service life of components by up to 30% and to increase their productivity as part of an IIoT network by 8-12%.
With energy performance contracting for drive applications, the savings in energy costs can in turn be used directly to refinance the optimization measures. The projects at Siemens are carried out according to a four-stage process, which reduces the investment risk for users to a minimum with binding savings promises. The investments are self-financing from the energy cost savings achieved – without restricting cash flow or using additional credit.
With Energy Performance Contracting, increases in efficiency are converted into a direct return on investment and so ensure economic success
Dual benefit: simply reuse energy
An essential component in increasing energy efficiency in the overall system is the use of energy storage. For example, Erfeba lngo Kneer GmbH is setting new standards in terms of energy efficiency with the innovative energy storage of its high-bay storage system: the storage and retrieval system from Erfeba is fully equipped with controlled electrical SINAMICS S120 drives from Siemens. Generator-based operation enables the drives to repeatedly convert and utilize the kinetic energy of acceleration and braking processes during storage and retrieval of the cassettes: like a mountain railway with a gondola moving up and down – only far more flexible. In the specific example, the energy requirement of the system could be reduced by 64% and the connection value by 60%.
The modular Siemens drive portfolio in the high-bay warehouse of Erfeba Ingo Kneer GmbH achieves a significant increase in productivity and energy efficiency
Even beyond storage and conveyor technology, the use of energy storage and energy networks results in enormous energy-saving potential for all industries and applications in which large masses are moved in opposite directions with electric motors. In the paper industry, for example, the unwinder’s braking energy is converted into kinetic energy for drives.
A look at the overall system is therefore worthwhile for all industries in which electric drive solutions are used: not only to optimize the electric drive alone, but above all to effectively use the synergies between the components and so achieve the greatest benefit for environmental protection and entrepreneurial success. The motors, converters, and digitization portfolio from Siemens already offers the right solutions for current and future energy-efficiency standards – and so the possibility of setting up or converting the entire drive-train for every application in a climate-friendly, future-oriented manner.