Electric motors and drives are electrical components utilised in fans to turbines, from heating, ventilation and air conditioning systeÂms to irrigation systems. These components are imÂportant because they are used to deÂtermine and adÂjust the speed at which electric devicÂes operate. They account for approximately 28 per cent of the total electricity consumption in the country. Further, arouÂnd 70 per cent of industrial electricity consumption and 38-40 per cent of commercial consumption is attÂriÂbutable 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 foÂcus on purchasing efficient motors and replacing ageing motors and drives, frÂom a techno-economic perspective.
Emerging technology trends
Motor manufacturers are leveraging new-age advanced technologies to meet inÂdustries’ requirements in terms of diÂgiÂtalisation. The new generation of moÂtors and drives incorporate features such as data analytics, internet of things (IoT) and real-time monitoring, which help in more efficient utilisation of moÂtors. They can send data directly to the IoT platform and suggest a variety of solÂutions, 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 moÂtors 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, moÂÂtor data is extracted and sent to a smartphone or tablet.
In general, there are several other components that are operating alongside moÂtors at the same time. Motor current signature analysis, temperature and vibration monitoring can be combined to deÂliver real-time performance metrics. This can provide instantaneous and short-period performance comparisons to flag predictive and preventive maintenance needs. Real-time monitoring provides unÂequivocal 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 maintenanÂce team received an alert that one had hiÂgher 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 esÂtimates, 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 reÂquirements, rather than simply cutting off the airflow, while remaining at maximum capacity. The most common area for installing VSDs in industrial moÂtors are pumps, fans and compressors, where there is infrequent and partial usÂage 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 proÂvides cost savings attributed to reÂduÂcÂed energy costs, coupled with lower maÂinÂtenance costs.
In recent years, companies have launchÂed the IE5 grade of motors, which incorporate synchronous reluctance technology, to improve efficiency and operatiÂonal performance. The rotor in a synchÂronous reluctance motor has no magnets or windings and suffers virtually no poÂwer losses. And because there are no maÂgneÂtic forces in the rotor, maintenanÂce is as straightforward as with induction motoÂrs. These motors combine the performaÂnce of permanent magnet moÂtors with low operations and maintenance (O&M) cost of induction magnets, to maximise efficiency and minimise downtime. Additionally, the absence of maÂgnetic force in the motor helps reduÂce temperature in the motor, thereby proÂlonging 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 imÂported 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, abÂout 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 deÂmand in the market and increase in deÂmand for pumping motors and IE3 moÂtors, owing to regulations.
In India, most of the motors are energy intensive and quite inefficient, leading to issues such as elevated operational coÂsts 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 expeÂnditure on their upkeep and maintenÂaÂnce, as most of them have been running for 15 years or more. The use of inÂeffiÂcient motors significantly increases the O&M costs of industrial units.
It is estimated that nearly 2 million moÂtors are manufactured in India each year and most of them are IE1 grade. In order to control this trend, the DepartÂmeÂnt 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 InÂdian Standards. As per the order, motors need to conform to a base standard of IE2 three-phase moÂtors at a minimum.
Furthermore, it is noteworthy that upÂgraÂding an IE1/IE2 motor to an IE3 moÂtor 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 efÂficient motors in industries, Energy Efficiency Services Limited (EESL), a puÂblic sector company, launched the NatioÂnal Motor Replacement ProgramÂme, 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 enÂergy savings potential of more than 5 billion kWh. The demand reduced by HEMs will be equivalent to 600 MW.
ESCO model
National Motor Replacement ProgÂramÂme, aims to create infrastructure to acÂcelerate the adoption of HEMs, specifically IE3 efficiency class, through an inÂnovative financing business model.
In general, most customers interested in IE3-grade motors are unwilling to purchase them because of their high upÂfront and interest costs and scepticiÂsm over the quality of higher-grade moÂtors. MoreÂover, efficient equipment, afÂter discounting for its high upfront capital costs, teÂnds to yield benefits over a decaÂde or so, which leads most buyers to prefÂer electrical equipment with lower upÂfront costs, despite the higher lifetime costs.
EESL’s unique energy service company (ESCO) business model ensures a successful transition to more efficient moÂtoÂrs and electrical equipment with its self-sustaining and virtuous financial cycle. By engineering a financially viable model, EESL strives to drive the adoptiÂon of efficient components. It allays coÂnÂsumer concerns about quality and performance by providing guarantees.
In line with the deÂemed savings meÂthÂod, consumers will pay a certain percentage of the amÂoÂunt they saved on electricity bills by utÂiÂlising these energy efficient motors. These energy savings are then monetisÂed, of which a certain portion is reÂpaid 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 (eqÂual 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 yeÂars, after which the buyer can claÂim the full amount. This is a win-win proÂposition for all parties involved.
During 2020-21, EESL signed agreements with over 30 major industries to replace over 1,200 IE3 motors, enabling energy saÂvings 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 upÂfront cost of installation. NoneÂtheless, these ageing moÂtors and drives are exÂpensive, after facÂÂtoring in the opportunity cost of downÂtime coupled with the huge energy consumption incurred by its continued usage over a lifetime. HenÂce, it is incumbent upon the governmeÂnt, users, manufacturers and financial institutions to collaborate and develop policies enabÂling the adoption of efficient motors, given that they reduce enÂergy costs as well as maintenance cosÂts to an unpreÂcedented degree.