This blog series will look at motor drives from many different angles - from architectures to power management, from connectivity to cybersecurity, and much more in between. We are starting from the top down and this first blog looks at how making motors more energy efficient can play a significant role in reducing the harmful emissions which are contributing to climate change.
The Paris Agreement in 2015 set out a plan to limit global warming to 1.5°C by 2050. Meeting the 1.5°C target in 2050 requires an approximately 70% reduction in CO2 emissions from 2018 levels. The current trajectory of global warming has the potential to cause major economic, societal, and environmental disruptions. The world has already warmed by 1.1°C and experts say that it is likely to breach 1.5°C in the 2030s.
Figure 1 outlines a path to the 1.5°C target by reducing CO2 emissions to under 10 Gt CO2, as covered in World Energy Outlook 2019 [1]. In that report, the International Energy Agency (IEA) looks at two scenarios for the trajectory of global emissions. The first is the Stated Policies Scenario, which estimates emissions based on publicly announced government policies. The second is the Sustainable Development Scenario, which looks at additional paths to mitigating emissions. The largest opportunity to reduce CO2 emissions as part of the IEA’s Sustainable Development Scenario is gains in energy efficiency, accounting for 37% of the Sustainable Development Scenario’s reductions when compared to the Stated Policies scenario With 25% of CO2 emissions coming from industry in 2022 [2], accelerating industrial energy efficiency investments will be an important part of the path to net zero emissions in 2050.
Figure 1: Path to CO2 emissions reductions [1]
Why Industrial Motors Matter
The global electricity supply in 2022 was 28,642 terawatt-hours, contributing 13.2 Gt of carbon emissions [3]. Industry consumes an estimated 30% of global electricity and within industry, electric motors make up approximately 70% of electricity consumption [1]. Clearly, the efficiency of these components is a potentially critical contribution to the efficiency savings identified in Figure 1. The most basic and lowest efficiency motion solutions are based on direct AC grid-connected 3-phase motors that use switchgear to provide on/off control and basic protection. These motion solutions run at a relatively fixed speed, independent of any load variation. Adjustments in output variables (such as fluid flow in pumps and fans) are implemented with mechanical controls such as throttles, dampers, and valves, whereas significant speed changes are implemented with gears.
Figure 2: The part played by Industrial Motors in global energy usage
The addition of a rectifier, DC bus, and a 3-phase inverter stage, as illustrated in Figure 3(b) creates an inverter with variable frequency and a variable voltage output that is applied to the motor to enable variable speed control. This inverter driven motor significantly reduces system energy consumption by running the motor at the optimum speed for the load and application. Examples include higher efficiency pumps and fans. When added to the existing motor of a pump, fan, or compressor, an inverter can potentially reduce power consumption between 25% and 60%, depending on the motor and application[4,5]. For higher performance motion control applications, a VSD (Figure 3(c)) enables accurate torque, velocity, and position control.
Figure 3: (a) Grid-connected AC motor (b) Inverter fed motor (c) Variable speed motor drive
It is estimated that only about 1-in-6 of all deployed motors in the industry are inverter driven or connected to a VSD[6]. By moving more deployed motion assets from grid-connected motors to inverter-driven or VSDs, it is possible to significantly reduce the energy consumption and CO. These reductions in energy consumption would enable more sustainable manufacturing with reduced CO2 emissions. It has been estimated that if all deployed motor driven systems were operated at maximum efficiency, it would reduce global electricity demand by 10% and remove 2490 Mt of CO2 emission in 2030 [7].
Motor Efficiency Standards
To accelerate the deployment of higher efficiency motor driven systems, the International Electrotechnical Commission (IEC) has contributed to the definition of energy efficient electric motor standards. This includes the IEC 60034-2-1 test standard for electric motors and the IEC 60034-30-1 classification scheme comprised of four levels of motor efficiency (IE1 through IE4), with the IE5 level due to be introduced in the future. The higher-level standards can be achieved either through more efficient motor design or through the addition of an inverter or VSD to a standard motor design. As the efficiency classes become more stringent, meeting them by improved motor design alone is becoming more and more challenging, and costly. Alongside the additional benefits provided by variable speed control in the application, the case for VSD-attach to most industrial motors is becoming more compelling.
The next blog in this series will highlight the other trends in industrial automation – apart from energy efficiency – that have been driving the evolution of motion control away from simpler grid-connected machines to highly controllable multi-axis VSD-based systems.
References
[1] World Energy Outlook 2019. International Energy Agency, 2019.
[2] World Energy Outlook 2022, International Energy Agency.
[2] Electricity Market Report 2023. International Energy Agency, February 2023.
[4] Achieving the Paris Agreement: The vital role of high-efficiency motors and drives in reducing energy consumption. ABB, 2021.
[5] Applications of variable speed drive (VSD) in electrical motors energy savings. R. Saidur, S. Mekhilef, M.B. Ali, A. Safari, H.A. Mohammed, Renewable and Sustainable Energy Reviews, Jan 2012.
[6] U.S. Industrial and Commercial Motor System Market Assessment Report, Volume 1. Lawrence Berkeley National Laboratory, January 2021
[7] Energy-Efficiency Policy Opportunities for Electric Motor-Driven Systems. International Energy Agency 2011.
Top Comments