Electric motors and drives are electrical components utilised in fans to turbines, from heating, ventilation and air conditioning systems to irrigation systems. These components are important because they are used to determine and adjust the speed at which electric devices operate. They account for approximately 28 per cent of the total electricity consumption in the country. Further, around 70 per cent of industrial electricity consumption and 38-40 per cent of commercial consumption is attributable to motors and drives.
According to some studies, the energy cost of running an electric motor over 10 years is at least 30 times the original purchase cost of the motor. Hence, it is vital for organisations and households to focus on purchasing efficient motors and replacing ageing motors and drives, from a techno-economic perspective.
Emerging technology trends
Motor manufacturers are leveraging new-age advanced technologies to meet industries’ requirements in terms of digitalisation. The new generation of motors and drives incorporate features such as data analytics, internet of things (IoT) and real-time monitoring, which help in more efficient utilisation of motors. They can send data directly to the IoT platform and suggest a variety of solutions, depending on the situation.
Additionally, embedding motor performance sensors could improve the motor performance tremendously at a low cost and with limited downtime. To keep motors running optimally, plant managers can install retrofit sensors. With important metrics such as vibration and temperature monitored in real time, built-in predictive maintenance analytics will identify future problems, ahead of failure. With sensor-based applications, motor data is extracted and sent to a smartphone or tablet.
In general, there are several other components that are operating alongside motors at the same time. Motor current signature analysis, temperature and vibration monitoring can be combined to deliver real-time performance metrics. This can provide instantaneous and short-period performance comparisons to flag predictive and preventive maintenance needs. Real-time monitoring provides unequivocal information on the functioning of these systems and identifies inconsistencies to determine electrical and mechanical faults.
For instance, in Brazil, one manufacturing plant implemented this technology on motors driving four identical air recirculating machines. When the maintenance team received an alert that one had higher vibration levels than the acceptable threshold, their heightened vigilance enabled them to solve the problem.
Energy efficient solutions
Another energy efficient strategy to augment efficiency of IE3 or sub-IE3 motors is to install variable speed drives (VSDs) in motors. VSDs adjust the speed of an electric motor, based on the application requirements. Without this control, the system simply brakes when less force is required, expelling the wasted energy as heat. Therefore, VSDs save energy with every rotation. According to industry estimates, using a VSD to slow down a fan or pump motor from 100 per cent to 80 per cent can save as much as 50 per cent on energy use. In a fan application for instance, VSDs reduce the airflow as per requirements, rather than simply cutting off the airflow, while remaining at maximum capacity. The most common area for installing VSDs in industrial motors are pumps, fans and compressors, where there is infrequent and partial usage of motors depending on time, temperature and output requirement.
Further, plants and industrial units can improve the efficiency of infrequently/ partially working motors by installing soft starters. These devices temporarily reduce the load and torque in the power train and the electric current surge of the motor during start-up. Similarly, for machine equipment, a slower start uses less energy and results in less mechanical stress on the motor and shaft. Over the lifespan of the motor, a soft starter provides cost savings attributed to reduced energy costs, coupled with lower maintenance costs.
In recent years, companies have launched the IE5 grade of motors, which incorporate synchronous reluctance technology, to improve efficiency and operational performance. The rotor in a synchronous reluctance motor has no magnets or windings and suffers virtually no power losses. And because there are no magnetic forces in the rotor, maintenance is as straightforward as with induction motors. These motors combine the performance of permanent magnet motors with low operations and maintenance (O&M) cost of induction magnets, to maximise efficiency and minimise downtime. Additionally, the absence of magnetic force in the motor helps reduce temperature in the motor, thereby prolonging the lifetime of the motor and improving its reliability.
Indian market
According to the Indian Electrical and Electronics Manufacturers’ Association, the market size of motors and AC generators is estimated at about Rs 65.39 billion as of 2020-21.
In April-September 2021, India imported motors and AC generators worth Rs 22.97 billion, 60 per cent more than in the same period in the previous year. At the same time, the country exported motors and AC generators worth Rs 17.83 billion, about 43 per cent more than in the same period in the previous year.
Overall, demand for motors and drives will grow substantially in 2021-22, given that it was impacted in the previous year due to the pandemic-induced recession. Additionally, sector experts expect that a significant proportion of the growth will be driven by a revival of the overall demand in the market and increase in demand for pumping motors and IE3 motors, owing to regulations.
In India, most of the motors are energy intensive and quite inefficient, leading to issues such as elevated operational costs and high emissions from industries and power plants. It is estimated that 90 per cent of the currently installed motors are at the IE1 and sub-IE1 levels. In addition, these motors encounter frequent failures and require regular expenditure on their upkeep and maintenance, as most of them have been running for 15 years or more. The use of inefficient motors significantly increases the O&M costs of industrial units.
It is estimated that nearly 2 million motors are manufactured in India each year and most of them are IE1 grade. In order to control this trend, the Department for the Promotion of Industry and Internal Trade issued a quality control order on August 1, 2018, mandating all imported and domestically manufactured motors to conform to the revised standards specified by the Bureau of Indian Standards. As per the order, motors need to conform to a base standard of IE2 three-phase motors at a minimum.
Furthermore, it is noteworthy that upgrading an IE1/IE2 motor to an IE3 motor pays back for itself through energy savings and decline in downtime and maintenance costs in three years. Hence, in order to promote the adoption of energy efficient motors in industries, Energy Efficiency Services Limited (EESL), a public sector company, launched the National Motor Replacement Programme, with the specific objective of funding the voluntary replacement of inefficient motors with IE3 motors. The programme targets the replacement of 120,000 motors in the first phase, with an aggregate annual energy savings potential of more than 5 billion kWh. The demand reduced by HEMs will be equivalent to 600 MW.
ESCO model
National Motor Replacement Programme, aims to create infrastructure to accelerate the adoption of HEMs, specifically IE3 efficiency class, through an innovative financing business model.
In general, most customers interested in IE3-grade motors are unwilling to purchase them because of their high upfront and interest costs and scepticism over the quality of higher-grade motors. Moreover, efficient equipment, after discounting for its high upfront capital costs, tends to yield benefits over a decade or so, which leads most buyers to prefer electrical equipment with lower upfront costs, despite the higher lifetime costs.
EESL’s unique energy service company (ESCO) business model ensures a successful transition to more efficient motors and electrical equipment with its self-sustaining and virtuous financial cycle. By engineering a financially viable model, EESL strives to drive the adoption of efficient components. It allays consumer concerns about quality and performance by providing guarantees.
In line with the deemed savings method, consumers will pay a certain percentage of the amount they saved on electricity bills by utilising these energy efficient motors. These energy savings are then monetised, of which a certain portion is repaid to the ESCO as EMI and the remaining is retained by the buyer. In this case, 20,139 kWh of energy savings translate into Rs 140,972 of monetary savings in electricity bills annually. The buyer of the motor pays 58.83 per cent of the energy savings (equal to Rs 82,933) as EMI to the ESCO, while retaining Rs 58,040. This process of repayment of a portion of the monetised energy savings is done for three years, after which the buyer can claim the full amount. This is a win-win proposition for all parties involved.
During 2020-21, EESL signed agreements with over 30 major industries to replace over 1,200 IE3 motors, enabling energy savings of 416,535 kWh and an emission reduction of 4,240 tCO2 annually.
Conclusion
Although motors and drives account for a major portion of the electricity consumption, consumers continue to use sub-IE2 motors, owing to their low upfront cost of installation. Nonetheless, these ageing motors and drives are expensive, after factoring in the opportunity cost of downtime coupled with the huge energy consumption incurred by its continued usage over a lifetime. Hence, it is incumbent upon the government, users, manufacturers and financial institutions to collaborate and develop policies enabling the adoption of efficient motors, given that they reduce energy costs as well as maintenance costs to an unprecedented degree.