Energy and Cost Savings

Real-time monitoring for efficiency, safety and predictive maintenance of motors and drives

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.

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