Energy management: What’s next for manufacturing?
Small changes in how energy is managed in manufacturing can add up to millions of dollars in energy-consumption savings. See below for four tips for saving energy in motion-control applications.
Every company can be an energy company. Restaurants need energy resources to power the ovens and refrigerators that prepare our food. Service stations use electricity to run the tools that service our vehicles. And of course, food and automotive manufacturers use water, air, gas, electricity, and steam (WAGES) to produce the goods of daily life.
According to the Energy Information Administration’s 2011 International Energy Outlook, industrial energy consumption will grow by approximately 50% over the next two decades, from 191 quadrillion Btu in 2008 to 288 quadrillion Btu in 2035. As energy use continues to climb, energy costs are on the same upward trajectory with 63% of manufacturing plants reporting higher utility and energy costs in the past year, according to the 2011 MPI Manufacturing Study. One-fifth of plants saw energy costs rise by more than 10%.
To address these challenges, most industrial companies are starting to track energy consumption in some capacity, whether at a site-wide level or down to specific production lines. By monitoring consumption, these companies can make operational changes to reduce energy consumption and costs, such as scheduling production more intelligently, reducing clean-in-place operations, or sequencing asset start-ups to reduce the impact of peak loading. Access to historical data also permits management personnel to address power-quality issues whether intermittent or persistent, such as voltage sags or harmonics, thereby saving thousands of dollars in damaged machines or poor-quality product coming from those machines, and avoiding penalty fees associated with power-factor problems on the energy grid.
While this type of data monitoring and analysis is critical to improve (you can’t improve what you can’t measure), many companies are starting to ask, “What’s next?” Once the data is collected and the low-hanging fruit addressed, what else can an industrial energy consumer do to continue minimizing consumption and maximizing efficiencies?
Beyond collecting energy-consumption data about machine requirements and product consumption, savvy, energy-conscious companies proactively respond to internal and external conditions, synchronizing real-time energy usage with production processes.
For example, few facilities operate “lights out” (that is, running without any human intervention), but thousands of plants rely heavily on automated equipment and processes. Many production environments couldn’t exist any other way. Yet automation often requires equipment to follow strict scheduling and routines, with few changes to accommodate different parts or products. During one shift, production modifications only may occur to resolve abnormal conditions that threaten product quality or plant safety (for example, when equipment stops and maintenance intervenes).
Regardless of where a company might be on the journey toward a more energy-efficient production infrastructure, every industrial consumer of water, air, gas, electricity, and steam (WAGES) resources can improve.
Automation can assume a new critical role in improving operations, influencing safety and overall equipment effectiveness (OEE, quality, yield, and uptime), and affecting energy consumption. Making WAGES information visible via internal dashboards keeps managers and workforces focused on capturing further energy-management improvements and accrues significant cost, compliance, and performance benefits. Without regular measurements, reviews, and revisions—systematic PDCA (plan, do, check, adjust)—efforts to continuously improve lose organizational benefit.
Visible and actionable WAGES data provides a PDCA cycle that allows the workforce to constantly see and resolve issues. It’s especially important to secure ongoing gains because improved management of energy consumption won’t necessarily deliver substantial improvements immediately. Energy management is a marathon, rather than a sprint, with savings measured in hour-to-hour and day-to-day increments: When and why did a machine exceed typical energy draw? Why did an equipment changeover cause start-up surges? Why did a component change extend the production cycle into a peak-draw period?
Visibility is the only practical way to track conditions (successes and failures) and gauge the effectiveness of practices, processes, devices, and equipment in minimizing energy consumption. But unlike PDCA cycles based on human observation and intervention—involving managers and team members that perform the activities of plan, do, check, and adjust—the key to energy improvement lies within the streams of data running to, through, and from equipment. Process automation supercharges PDCA energy management.
Save motion: Four energy tips
To enable this, industrial technologies like variable-frequency drives (VFDs) and servo and linear-motion devices are necessary to transfer energy intelligence into energy-usage action. VFDs, as an alternative to fixed-speed controllers and throttling devices, improve operating performance, control capability, and energy savings in four main ways:
1. Avoid peak demand charges: Ramp motors up to speed gradually during times of peak demand.
2. Optimize power in relation to load: Use the precise (not excess) amount of energy required by the equipment to fulfill demand.
3. Generate energy: Many VFDs are capable of regenerating power, which can be routed back to the system or sold to utilities.
4. Optimize performance: Intelligent motor controls integrate advanced networking and diagnostic capabilities to optimize performance, increase productivity, and reduce energy use.
In addition, Allen Avery writes in an ARC Advisory Group report: “A willingness to apply state-of-the-art information and automation technologies can have a major impact on the success of energy-management programs. Applications such as advanced process control, energy-management software packages, and decision support can be used to optimize processes and coordinate energy-management activities across functional areas in the plant. Judging from our survey, leaders [a benchmark set of high-performing companies] are more likely to apply new technologies to the problem of energy management and to invest in technology upgrades such as boiler control systems, digital control systems, and intelligent field devices. They are also more likely to leverage information technology to collect, manage, and analyze energy-management information. Leaders also try to envision ways to fundamentally change the process itself to reduce energy consumption, and are more willing to put their R&D departments to work on the problem.”
Automated data collection and management, along with use of motor controls and VFDs, allow manufacturers to make incremental changes in how processes and equipment operate—slowly ramping up machines—with all these small changes adding up to millions of dollars in energy-consumption savings.
Regardless of where a company might be on the journey toward a more energy-efficient production infrastructure, every industrial consumer of WAGES resources has an opportunity to improve.
- Mary Burgoon is market development manager, sustainable production, power generation and energy management, Rockwell Automation. Edited by Mark T. Hoske, content manager, CFE Media, Control Engineering and Plant Engineering, firstname.lastname@example.org.