From Measurement to Action

In 2024, industrial electricity consumption in Germany stood at approximately 217 TWh/year. Electric and electro-hydraulic drive systems account for a significant share—46%—of this grid-supplied electricity. Around 70% of that figure is attributable to motor-driven systems such as pumps, fans, and compressors, making them some of the most energy-intensive applications. At the same time, rising energy costs and regulatory requirements—such as the Energy Efficiency Act (EnEfG)—are intensifying the demand for energy-efficient retrofit solutions. Modern variable frequency drives, combined with high-efficiency motors, enable massive energy savings, particularly during partial-load operation. The ZVEI estimates an EU-wide energy-saving potential of 121.5 TWh/year through the use of energy-efficient drive technology.

In practice, it often turns out that the potential for savings lies not in the design of new systems, but in the existing machinery. A reliable data basis is crucial. Mitsubishi Electric therefore pursues an approach based on the systematic recording of load and energy profiles. The goal is to make real operating conditions visible and derive well-founded measures from them.

Clear patterns often emerge, especially in existing installations. Drive systems frequently run at partial load or idle for extended periods without any energy optimization. These operating conditions have a greater impact on efficiency than the nominal power rating of individual components.

Retrofitting as a technically and economically sound step

Electro-hydraulic systems offer some of the greatest potential for improving efficiency in existing installations, as they are often operated at constant speeds while actual power demand fluctuates significantly. In conventional systems, pumps frequently run at a constant speed, with flow rate regulated via valves. This results in substantial energy losses, particularly during partial-load or idling phases. Retrofitting with variable frequency drives (VFDs) allows the motor speed to be adjusted according to demand, ensuring the pump delivers only the power actually required. This significantly reduces energy consumption, as power draw in pump systems depends heavily on rotational speed.

Additionally, high-efficiency motors—such as synchronous reluctance motors—can be used in the electric drive system. These reduce losses within the motor itself and, when combined with VFDs, achieve high levels of efficiency, reaching the highest international energy efficiency class (IE5) for electric motors.

This retrofit approach creates a two-stage effect: speed control accounts for the largest share of process energy savings, while the motor component is further optimized through more efficient technology.

Peak load reduction and energy recovery

Beyond direct energy savings, there are additional operational benefits. Using modern variable frequency drives from Mitsubishi Electric makes it possible to reduce peak loads and recover energy generated during braking processes.

These functions have a direct impact on grid stability and the supplementary energy supply for production processes via regenerative energy. Fieldbus connectivity and integration into an energy management system allow for the systematic recording and evaluation of energy consumption, as well as continuous improvement of energy efficiency in accordance with EN 50001.

The combination of measurement, analysis, and targeted modernization makes it possible to meet regulatory requirements—such as those set out in the Energy Efficiency Act—while simultaneously making operations more efficient.

Author: Thomas Droth, Head of Industry Solutions