AC Drives Reduce Energy Costs and Help Process Improvement

​Naresh Kumar Surepelly and Rajabahadur V. Arcot 

Discrete and process industries widely use AC motors.  Besides the emphasis on speed control and energy costs, issues such as greater reliability, soft-starts, higher power factors, improved efficiency, and monitoring the health of motors have also become very important challenges for industrial companies.  AC drives play a vital role in overcoming some of these challenges, especially in lowering energy costs and achieving process improvement. 

Currently, India’s total installed power generating capacity is over 180,000 MW, and over 40 percent of energy is consumed by industries.  The country’s demand for electric power outstrips supply by about 10 percent, and almost one third of the country’s population has no access to electricity.  Additionally, rising energy and natural gas prices, environmental concerns, and such others compel industries and the State to manage the use of energy efficiently.  Energy management has become very critical as it lowers productivity and slows down the country’s economic growth.  Recently, the State has introduced new policy initiatives to manage energy efficiently, which include mandatory measures, guidelines, and market driven mechanisms. Many industrial companies are vigorously working to reduce their energy costs in compliance with the State’s mandatory stipulations.  Adoption of AC drives helps industrial companies to drastically reduce their energy costs. 

AC drives offer many benefits to industrial companies; the most important benefit is adapting the motor speed to the actual need, thus reducing energy consumption and CO2 emissions.  Industries, such as cement, chemical & petrochemical, electric power, metals & mining, water & wastewater, marine, and oil & gas are highly energy intensive and should deploy energy-conserving devices, such as AC drives that save significant energy by efficiently controlling the speed of electric motors based on the actual need.  Uses of AC drives in industries span various control applications, which include fans and pumps, grinding mills, kilns, crushers, conveyors, mine hoists, compressors, extruders, mixers, test benches and blowers.  

Energy-saving opportunities for using AC drives in industrial applications are abundant.  In fan/pump applications, which are pervasive in the manufacturing and infrastructure industries, induction motors dominate and therefore are excellent candidates to benefit from AC drives.  

Especially, the electric power industry in general will also become more efficient with the use of AC drives.  Approximately 9 percent of the overall total capacity of a power generation plant is lost or consumed within the power generation plant itself.  When energy guzzlers, such as forced draft, induced draft, and primary fans, along with boiler feed water pumps, all utilize AC drives, it will increase the saleable electric power, and thereby increase electric power companies’ profit margins.  

Apart from helping users reduce energy costs and gain competitiveness, the application of AC drives also results in process controllability improvement, such as reliable product quality, improved speed control, process improvement, and reliable start under all conditions.  These factors help in reducing the total cost of ownership (TCO).  Additionally, the average selling prices (ASP) of AC drives have decreased compared to the previous years.  With all these benefits, the use of AC drives clearly increases the return on investment and reduces the payback period.  

Some AC drives suppliers in India are offering AC drives to industrial companies on energy performance contracting (EPC) basis.  EPC allows industrial companies to pay the suppliers based on their energy savings on a contractual basis.  Currently, along with EPC a few suppliers are also offering free energy audits, guaranteed energy savings, and such others.   In order to compete and emerge successful the other suppliers will also adopt strategies, such as energy performance contracting (EPC).  

The industries which use large sized AC motors, such as cement & glass, electric power generation, metals & mining, oil & gas and others get excellent energy saving benefits from the use of medium voltage AC drives.  Similarly, the industries which use low power AC motors, such as building automation, food & beverage, textile, and machinery industries get excellent energy saving benefits from the use of low power AC drives.

ARC believes that AC drives suppliers should create awareness about the energy saving potential and process improvement benefits of using AC drives.  End users would benefit if suppliers are persuaded to undertake performance commitments in deployment of MV AC drives. Recently, ARC published a market outlook study on LP AC drives in India, and another well-researched study on the market for MV AC drives will be published soon.  These studies give an overview of the scope, market share, factors contributing and constraining growth, forecast trends and profile leading suppliers of LP and MV AC drives in India. 

We welcome your views on this subject. For indepth information about AC drives do contact us for the market outlook studies. Please write to nsurepelly@arcweb.com or raja@arcweb.com.