What is the average cost of providing one cubic foot per minute (cfm) of compressed air?
We are glad that you are alert to compressed air energy costs. According to the Advanced Manufacturing Office in the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy (EERE), manufacturers spend over $5 billion per year on energy in compressed air systems, and, optimizing compressed air systems can improve energy efficiency 20%-50%.
A rough estimate of the cost of compressed air is one cent per operating hour per cubic foot of compressed air (see example calculation below). Details of the equipment involved, conditions under which it will be operating, and the cost of energy from the local utility can influence this amount.
Note that large manufacturing plants generally employ centrifugal compressors to meet their compressed air needs. These compressors commonly provide from 1,000 to 5,000 cfm of airflow with discharge pressures up to 125 pounds per square inch-gauge (psig). Centrifugal compressors have an operating power requirement of 16 to 20 kW per 100 cfm of plant air provided. "Plant air" that is used to drive various pneumatic tools is typically provided in the range of 100 to 125 psig.
If an average centrifugal compressor requires 18 kW/100 cfm, 0.18 kW of electrical demand is required to provide one cubic foot per minute of compressed air. At an industrial electrical rate of $0.05/kWh, the hourly energy cost for providing one cfm of delivered air is about 0.9 cents.
0.18 kW x 1 hour x $0.05/kWh = $0.009 or 0.9 cents per hour
The compressed air operating cost is dependent on compressor type and local energy rates. For instance, a double-acting reciprocating compressor typically requires 15 to 16 kW/100 cfm, while a single-stage lubricant-injected rotary screw compressor requires 18 to 19 kW/100 cfm. A lubricant-free rotary screw compressor typically requires 20 to 22 kW/100 cfm. Electricity prices can vary tremendously. Additionally, the cost of compressed air is impacted by air pressure, altitude, and the temperature of incoming air.
The Advanced Manufacturing Office in the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy (EERE) provides information on energy efficiency, environmental performance, and productivity. One of its goals is that industry gains easy access to near-term and long-term solutions for improving the performance of motor, steam, compressed air, and process heating systems. On-site assessments and many other tools are available.