For example, while advanced control and real-time process optimization solutions often include energy consumption as variables for optimization, if the process units themselves were not designed to optimize energy efficiency, much opportunity for saving energy is lost.
Furthermore, automation suppliers are just now beginning to explore the potential energy savings that can be realized by integrating plant electrical control and process control systems. And enterprise solution suppliers have only recently begun to explore how their production management and enterprise asset management (EAM) solutions can be extended to help users measure and manage energy consumption.
As a result, energy management and energy-efficiency initiatives are often incomplete and insufficiently coordinated. This can be very costly for manufacturers, and will only increase as both energy costs and costs associated with carbon emissions rise.
According to an ongoing ARC Advisory Group survey, many end-users have implemented “homegrown” EMS solutions. Clearly, compared to commercial solutions based on industry standards and designed to be both easily configurable and scalable, homegrown solutions tend to be more costly, if not impossible, to support over time. Not surprisingly, most homegrown solutions never grow beyond being point solutions. This situation is regrettable because energy is the second largest expense for industry, and end-users end up paying too much for their often-ineffective homegrown solutions.
Most energy-intensive operations experience considerable variability in energy consumption due to changing operating conditions, equipment degradation, fluctuating market demand and inefficient control strategies. As a result, plants typically use more energy than necessary, yet are unable to improve efficiency because they lack real-time performance information.
The ultimate energy efficiency of the production and energy generation processes begins with conceptual equipment and process design. Heat recovery and heat integration at the equipment-, plant-, and site-wide levels should be taken into account, along with product packaging and recycling. Energy-efficient equipment, such as variable speed drives and more efficient pumps and motors, can reduce energy consumption to a significant degree over the long-term plant lifecycle.
Monitor and optimize
In daily operations, energy usage should be monitored, and for complex processes, optimized in close to real time. In this domain, process operations and control are intimately connected. Most energy-intensive operations, such as those found in a refinery or chemical plant, experience considerable variability in the consumption of energy due to changing operating conditions, equipment degradation and fluctuating market conditions, plus poorly tuned control loops, inappropriate control strategies and/or lack of process optimization. When real-time information is not available, or if control applications are not easily maintainable or adaptable, plants use more energy than necessary.
Users need an adaptive implementation framework for energy management that coordinates initiatives in different domains across different time scales, with a strategy, a management system and competence centers for sharing best practices.
Florian Güldner, [email protected], is Automation Analyst; David Humphrey, [email protected], is Director of Research, Europe; and Valentijn de Leeuw, [email protected], is Director of Consulting; at ARC Advisory Group Inc., in Dedham, Mass.
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