Applying energy efficiency concepts to electric motors and electrical installations

Energy efficiency has been defined as the “first fuel of a sustainable, global energy system” by the International Energy Agency (IEA). It is a cost-effective means for supporting the growing demand for energy while simultaneously limiting negative consequences to the environment. Yet, it is often an overlooked source for energy.

Aspects of energy efficiency
Aspects of energy efficiency as defined in Guide 118

The IEC defines energy efficiency as the ratio between output performance compared with the input of energy. It consists of the following: using less energy for the same performance, using the same energy for better performance, or improving the conversion of energy into electricity.

Many energy efficient technologies and solutions are readily available. Investments and a commitment towards energy efficiency abound, yet a number of barriers inhibits the deployment of energy efficiency solutions. Lack of awareness of saving potential, a focus on devices rather than systems which leads to a lower return on investment and a preference for lower cost rather than life-cycle gains are some of the barriers that impede harvesting the full potential of energy efficiency.

Standardization can offer solutions to help overcome these barriers by, for example, providing definitions and measurements of performance, disseminating and promoting energy efficiency technologies and establishing minimum energy performance requirements.

The IEC has set up the Advisory Committee on Energy Efficiency (ACEE) to help IEC technical committees adopt energy efficient solutions in their standardisation activity and support energy efficient technologies through their standards. According to ACEE Chair Philippe Vollet, “our first mission is to coordinate activities related to energy efficiency and provide guidance to technical committees”.

IEC ACEE has developed two guides, Guide 118 and Guide 119, which can be used by IEC technical committees to harmonize energy efficiency standardization and adopt a systems approach.

Understanding Guide 118

Guide 118 seeks to harmonize the energy efficiency standardization and raise awareness that IEC publications can impact energy performance in both positive and negative ways. It also provides a definition to the different aspects of energy efficiency that technical committees can address when planning their work in this area so as to support the energy efficiency improvement process.

Guide 118, together with Guide 119, promotes the use of a systems approach when addressing energy efficiency aspects in the context of standardization. In addition, IEC ACEE has published two practical case studies on how the concepts found in Guide 118 can be applied to low-voltage electrical installations and to electrical motors.

Low-voltage electrical installations

The case study on low-voltage electrical installations shows how international standards can be used to support the energy efficiency market and national energy efficiency policies. It is based on IEC 60364-8-1 which gives guidance on the design and assessment of low-voltage electrical installations based on the concepts found in IEC Guide 118. It is defined as a Group Energy Efficiency publication as per IEC Guide 119.

According to Jacques Peronnet, member of IEC ACEE and Chair of IEC TC 64, “IEC 60364-8-1 provides a method to assess the energy efficiency of an electrical installation based on parameters that influence efficiency. It is relevant for both new and existing buildings and can be used for industrial, commercial and residential premises.”

Defining the boundaries

Boundaries need to be defined in order to understand what will be addressed in the optimization of energy usage. Circuits that are designed for energy optimization are known as meshes and generally refer to a zone in the building such as the floor or a room and a type of usage such as lighting or HVAC. Meshes are optimized to ensure the lowest energy consumption and cost in comparison with another solution.

Design principles and driving parameters

The optimization of electrical energy usage can be aided by the appropriate design and consideration given to the external factors that impact energy usage in a building.

Design aspects such as the availability of local energy generation and storage as well as the arrangement of circuits need to be considered. The external driving parameters include factors that have an impact on energy usage such as building occupancy, the seasons of year - such as winter or summer when electricity demands are higher - and the cost of the electricity.

Measurements are needed to assess the efficiency of a building and provide awareness about consumption. Examples of measurement tools include billing and energy usage analysis such as power meters.

As noted by Peronnet, “Buildings represent 40% of global energy demands of which a significant part is supplied by electricity. Finding ways to make energy usage more efficient can contribute greatly to a huge energy saving.”

Electric motors

Increasing the efficiency of electric motors can be an affordable means to reduce energy consumption and, given their widespread use, also have a considerable impact. According to Franco Bua, member of ACEE, “Electric motor systems represent more than 50% of the global electricity used, of which the large majority of electric motors are used in machines, pumps, fans, compressors, conveyor belts, etc. It is a genuine opportunity to increase energy efficiency”.

The IEC ACEE case study on electric motors is based upon Guide 118 and the standards developed by IEC TC 2: Rotary machinery, that specifically address energy efficiency. These standards address some of the energy efficiency aspects outlined in Guide 118 by providing a definition of the product scope, a scheme for energy performance classification, a method for measuring energy performance and guidelines for the selection and application of energy efficient motors.

Defining the boundaries

When defining the boundaries defining the scope of energy efficiency considerations, IEC 60034-1 and IEC 60034-30-1 can be used. While IEC 60034-1 provides general rating and performance definitions for motors, IEC 60034-30-1 defines the energy efficiency classes for motors known as the IE code. Together, these two standards enable the comparison between different motor technologies regarding their energy efficiency potential.

As noted by Bua, “Boundaries are key to energy efficiency since they define what will be the focus. However, many boundaries are possible, and the case study considers three possibilities”.

Measurement and improvement

Test methods are available in IEC 60034-2-1 to measure the energy efficiency of a motor. As a result, it is possible to set minimum energy performance requirements that can be compared and assessed as well as to compare industry products based on their energy efficiency.

IEC TS 60034-31 provides guidelines with information on various technologies that can be used to support and improve energy efficiency.

Supporting regulation

Because of their energy saving potential, electric motors have been a key focus for national energy efficiency policies. International standards have been an effective means to support national policies for minimum energy performance requirements for motors. As noted by Maarten van Werkhoven, member of ACEE, “A good set of standards will help regulators establish good energy efficiency regulations”.

The list of countries regulating the minimum energy performance requirements of motors is growing. According to Van Werkhoven, “Over time, we have witnessed not only an increase in the number of countries regulating motors but also an increase in ambition in their scope and efficiency requirements”.