Energy Consumption Management
Engineers need to look at energy consumption management as a direct means to improve profitability and productivity, not simply as a cost cutting measure. The first step involves seeing energy in 3D.
As an operations manager, control engineer, or machine operator, you have always been measured by your ability to cut costs. You have made just about every money-saving effort possible to maximize throughput and minimize waste. With everything squeezed about as tight as it can be, where else can you turn to help improve profitability?
While energy use has the potential to be a new frontier in cost savings, it is one of the most elusive and hard-to-manage costs in manufacturing. Traditionally, industrial energy consumption was seen one-dimensionally as an unavoidable cost of doing business. But the fact is, managing energy is actually a three-dimensional challenge: less, cheaper, and optimal.
While some energy is used for facility operations such as heating, cooling, and lighting the building, the majority of energy coming into the plant is used to power machinery, convert raw materials into intermediate products, generate steam, or facilitate production. Through behavioral and programming changes, you can actually use less energy—for example, by using more efficient equipment, reusing waste heat in your processes, or scheduling production to minimize energy-intensive changeover procedures. You also can use cheaper energy by managing where, how, and when energy is used in order to harness it when it is least expensive, such as during off-peak times.
Finally, you can optimize energy use to achieve production goals in the least expensive, most profitable way while balancing the many variables inherent to manufacturing. This dimension will ultimately have the most impact on financial performance, because you can actively manage energy as one of many inputs to the overall production equation. Here's how.
The greenprint approach
The seven pillars of energy management outlined here can be leveraged independently or simultaneously to transform your energy management strategy into a holistic and strategic program. It is a blueprint — or as we call it, a greenprint — for using your existing automation and power control assets to begin saving energy more effectively, and investing it more intelligently.
Pillar 1: Facility monitoring. Before you can begin to manage your energy consumption, you have to gain visibility into your energy usage and quality patterns. Chances are you’re already measuring your energy consumption at some level. To expand that knowledge, an assessment of your manufacturing facility can help establish the scope of an energy savings effort, define key metrics, and help you get the necessary resources in place in order to take a holistic view of energy usage throughout the facility.
You also can monitor the facility’s metering infrastructure to collect data about all energy resources — water, air, gas, electricity, steam, or other sources — in relation to equipment usage and environmental conditions. This data can then be logged and time-stamped in an energy historian software program to establish trends, discrepancies, and benchmarks for improvement.
With this big picture view, you can identify and make operational changes to help reduce energy consumption and costs. These might include shedding loads or lowering power levels when the facility is approaching peak use. The information gathered at the facility monitoring level also can help you understand and manage power quality issues such as voltage sags or harmonics that can damage equipment and cause power factor problems on the electrical grid. As a result, you can better protect your equipment, and avoid incurring penalty fees from utility companies that might charge for correcting power factor issues.
Assessing and monitoring usage should be an ongoing effort in order to identify variables such as how seasons might affect production variables and whether previously implemented improvements are continuing to perform as planned.
Pillar 2: Production monitoring. To understand plant floor energy consumption, work with your automation solutions provider to identify useful data collection points across machines and lines, and program your information systems to store and analyze that data. Once a system is in place, you can separate plant floor consumption data from facility consumption data, and gain a clearer view of exactly how much of the company’s overall energy use is consumed by the manufacturing process versus operational functions such as data centers and HVAC.
By gaining a clearer understanding of energy consumption at the plant-floor level, you could modify your equipment effectiveness calculations to include energy efficiency as part of the equipment’s overall performance metrics and optimizing performance curves of output versus cost. Consumption data also can be applied to traditional Lean Six Sigma tools to optimize operations. For example, a North American packaging company used plant floor energy consumption data with traditional value stream mapping data to re-sequence production operations and reduce energy costs. The company saved $66,000 in one year by moving energy intense operations outside the demand window and storing lower cost energy for work in progress.
Pillar 3: Capturing energy on the production BOM. Once manufacturing energy consumption data is stored and analyzed in the information system, you can begin to see clear trends in how energy has been used in various historical events such as a specific product cycle or batch. You no longer have to guess what energy consumption will be for similar production runs in the future; you actually can begin to project it in advance. In doing so, you move to a new pillar of the energy management architecture in which energy requirements are included in resource planning and scheduling decisions in the same way that raw materials are considered an element on bills of material (BOM).
Empirically tying energy consumption requirements to the production BOM helps you make proactive production decisions and better manage energy investments in a way that will generate a greater return. For example, by knowing that certain batches require more energy, you can move those batches outside peak windows. In addition, the unit-level energy consumption information becomes valuable input to your company’s sustainability reporting mechanisms.
Pillar 4: Modeling. Once you know how much energy is required to run a specific production cycle, you can leverage production simulation software tools to input variables such as peak and off-peak energy costs, raw material costs, labor, and projected emissions, and pre-test “what-if” scenarios to see how production outputs and costs will change as a result of modifications.
Within this pillar, you can optimize all production assets and forecast the most economical way to manufacture your products, using energy as one of the variables. You also can forecast the full sequence of production scheduling to optimize overall production.
Pillar 5: Controlling. With all the manufacturing applications and automation solutions on the plant floor generating data, the next pillar in the energy management architecture is to drive all data sets into a common automated solution that can identify, model, visualize and present control options, or automatically control production changes. While this might be beyond the scope of your day-to-day tasks, the modeling capability would automatically implement decisions without unnecessary intervention on your part. These decisions can extend past simple plant floor production variables to include additional variables that you are not directly measuring, such as last-minute staffing changes or urgent orders placed by key customers on short notice.
Pillars 6 & 7: Responding and scorecarding. Once you are confident about the energy management activities within the plant, your company can make external market and regulatory influences part of its overarching energy management strategy. It will then be possible to shift the perspective outside the facility and begin to focus on how to make intelligent economic decisions based on altering energy consumption in response to market fluctuation and regulatory demands.
Phil Kaufman is business manager, power and energy management products; and Marcia Walker is program manager, sustainable production, for Rockwell Automation.
Greenprint white paper
The seven-pillar greenprint methodology is outlined in more detail in a white paper titled “Industrial Energy Optimization: Managing Energy Consumption for Higher Profitability” and is available as a free download on the Rockwell Automation Web site at: www.rockwellautomation.com/solutions/sustainability/ .