Find facility efficiency first
The impact of rising energy prices is being felt in every corner office and boardroom.
The impact of rising energy prices is being felt in every corner office and boardroom. A recent Duke University study ranked high energy costs as the number one concern among U.S. executives %%MDASSML%% ahead of even healthcare costs and rising interest rates. Yet, remarkably, the same study revealed that only a minority of companies have made any attempt to improve the efficiency of their facilities.
Better energy management can, however, carry a sizable payoff. According to the Energy Cost Saving Council, aging buildings and out-of-date technologies coupled with sky-rocketing energy costs are creating tremendous economic opportunities to invest in energy management upgrades. With advances in energy efficiency over the last 10 to 20 years, there is dramatic room for savings in almost every area with a swift return on investment.
The first step toward realizing those savings is developing a comprehensive and integrated energy management plan. That plan will provide the blueprint for better controlling a plant’s energy use and ultimately improving its bottom line.
Begin with a complete energy audit
The first and most important step toward developing an energy management plan and reducing energy consumption is gaining a clear understanding of your existing use patterns and the technologies involved. That information can be captured only through a comprehensive energy audit.
During an energy audit, experts in energy efficiency typically identify the sources of energy use and prioritize them according to the greatest to least cost-effective opportunities for energy savings. However, additional savings can be generated by establishing energy use patterns in comparison to similar facilities in the region; evaluating peak demands and utility contracts; and unearthing potential maintenance issues, equipment efficiency levels and power quality problems.
By monitoring and analyzing energy use, companies improve internal awareness of how much and for what purposes energy is being consumed. That provides an opportunity to track needs and allocate resources in the most efficient way possible while avoiding negative impacts on productivity.
The role of monitoring
Accurate front-end energy use data is critical to understanding where the greatest potential savings lie and what progress has been made since system or process changes have been implemented. To capture the energy use data, facilities must rely on power monitoring systems.
Today’s electrical manufacturers offer a wide variety of option-rich and customizable power monitoring solutions. Circuit monitors can accurately measure electricity display inputs from other utilities, including gas, compressed air, water and steam. Users can track a variety of energy use metrics and use interval data information to create diagnostic reports or generate alarms notifying the facility manager of potential issues.
Through customizable reporting capabilities, advanced power monitoring systems allow users to derive electrical efficiency by measuring energy use against virtually any variable that’s important to them. A manufacturing plant may track the total kilowatt hours and benchmark that data against outside or inside temperature, time of day, production levels, time of year, square footage or any other quantifiable value.
While power meters on their own don’t reduce electrical consumption, their payback has been well documented. A study by the Energy Cost Savings Council revealed that meters and monitors have an average payback period of less than six months and an average return on investment of 200%.
Identify, fix the basics
Following a comprehensive analysis of plant equipment, processes and its electrical infrastructure, very often the initial recommendations in an energy management plan includes improvements to the most basic electrical issues. Finding lower consumption devices, improving power quality and ensuring power reliability are commonly the first issues addressed.
Low consumption devices %%MDASSML%% Once it is understood where and how the power within a plant is being used, the next step is to evaluate and potentially upgrade equipment with the greatest potential for savings. Often times energy efficient lighting upgrades are among the first projects undertaken, largely because of their quick return on investment. According to the Energy Cost Savings Council, energy efficient lighting generates an average project payback period of 2.2 years and a 45% return on investment, which is often a better payback than other energy-saving building system technologies.
For example, by replacing high-pressure sodium lights with T8 fluorescent fixtures, manufacturers can cut their consumption in half. A 400-W lamp can be replaced by a 200-W lamp, while improving the illumination quality in the process. In fact, high-output fluorescent lighting has lower lumen depreciation rates, better dimming options, virtually instant start-up, better color rendition and lower glare than conventional HID fixtures.
Lighting is just one area often considered to reduce consumption levels within a facility. High-efficiency transformers and HVAC systems, along with improved building insulation in major heat loss areas can be some of the most basic and therefore among the first step towards reducing energy consumption.
Power reliability %%MDASSML%% Power reliability also remains a vital concern among industrial manufacturers. The opportunity costs from an electrical supply disruption can run from tens of thousands to millions of dollars, due to lost production time and equipment damage.
When planning and implementing electrical upgrades that improve efficiency, ensure that all changes help to maintain or improve the overall level of reliability. Avoid introducing new potential points of failure into a system, which, while improving efficiency, could compromise reliability.
When considering power reliability, some of the most common solutions are automatic transfer or switching systems. Many facilities now install two electrical feeds from the utility or have on-site secondary power to run the plant in case of a utility failure. Stand-by generators with automatic throw-over systems and uninterruptible power supplies have also seen major technological advancements in recent years.
Power quality %%MDASSML%% Of course, power reliability can mean more than just a steady supply of electricity from the utility. It also means running equipment with high-quality power %%MDASSML%% free of spikes, sags, swells, harmonics or other anomalies that can damage equipment or cause it to fail prematurely.
Power quality is an important consideration for many industrial facilities. Poor power quality can be generated by multiple sources, including the electrical utility, nearby businesses or equipment within the plant. For example, drives used with the HVAC system or motors within the production process can commonly produce harmonics, which can potentially damage other sensitive electrical equipment on the power line.
Harmonics can also contribute to poor power factor within a plant. Power factor issues are common within facilities that carry significant loads from motors, welders and arc furnaces. These inductive loads reduce the plant’s power factor, and expose the manufacturer utility imposed penalties, which result in higher energy. Common remedies for harmonics or poor power factor often include 18-pulse drives or power factor capacitors.
Automate key processes
Exploring new ways to automate processes within the plant is also a key element of any energy analysis. To be effective, energy experts conducting the analysis must have a keen understanding of how the facility operates, the challenges that are commonly faced and the intended outcome. By fully understanding the major processes within a facility, they can help identify how energy and staffing efficiencies can be achieved through better automation technology.
Lighting control %%MDASSML%% Schedule-based lighting control systems are a common recommendation following energy audits of large manufacturing facilities. By pre-programming the lighting schedule into a central controller, branch circuits are automatically turned on or off, conserving electricity in the process. Many lighting control systems use controllers that fit into the lighting panelboard and feature an integrated Web server. Control can then be facilitated through a Web browser using any PC connected to the Internet.
Such systems can be set up to alert facility managers of alarms via e-mail, pager or cellular phone, and also generate custom reports for the building owner showing energy use profiles. Those reports are crucial when it comes to identifying lighting energy use trends and measuring savings.
Other lighting control technologies, such as motion detectors or ambient light-level sensors, can also play an important role in reducing consumption in office areas, conference rooms and restrooms. These additional input devices are programmed to override a schedule-based system and only initiate lighting when needed.
Improved motor control %%MDASSML%% In industrial environments, motors consume the majority of the overall electrical load. Finding new ways to manage and reduce their consumption can pay major dividends for manufacturers.
The installation of variable frequency drives and/or advanced motor control centers help to automate and better control motors used in the manufacturing process. Without VFDs or motor control centers, operators are often limited to the simple options of on or off when it comes to controlling production motors.
With improved motor control, the VFDs can be pre-programmed to run the motors at only a percentage of the maximum speed, saving energy in the process. What’s more, the VFDs or advanced motor control centers can communicate with the plant’s data network, and automatically increase or decrease motor speed depending on present conditions.
VFDs are also critical to reducing energy consumption within a facility’s HVAC system. In most facilities, the HVAC system only needs to work at full capacity on the 10 or so hottest days and the 10 or so coldest days of the year. On the other 345 days, the HVAC system may operate at reduced capacity by using a variable air volume system with a VFD to automatically match air flow to actual heating and cooling demands.
Continuous improvement for electrical systems
While power monitoring is an important front-end step for establishing benchmarks and identifying the areas with the greatest potential for improvement, it’s also important when it comes to maintaining and continually improving an electrical system.
When used in collaboration with sophisticated energy management software, power monitors allow facility managers to trend electrical use data and examine how process or equipment changes within a facility have impacted the overall operation, and potentially identify new ways in which greater efficiencies can be achieved.
Ongoing monitoring can also be a useful tool for improving maintenance and repair operations. Data trends can forecast and notify end users when discrete equipment parameters may be exceeded, allowing them to plan ahead instead of facing an unscheduled shutdown.
Today, advanced electrical distribution equipment such as switchgear, panelboards and molded case circuit breakers are IP-enabled for Ethernet connectivity, allowing facility managers to access information about individual pieces of equipment and overall energy use at any time and from anywhere.
Integrate multiple energy technologies
The steps involved in a complete energy analysis will likely vary depending on the facility’s age, the processes it employs and the industry in which it operates. One element, however, should remain constant across all large energy users: an effective energy management plan will adopt a multi-faceted approach that leverages multiple energy-saving technologies.
The most successful energy upgrades are those that adopt a whole-building approach, which leverages a combination of integrated building technologies, including lighting, HVAC, motors and drives, controls and automation systems. Companies that adopt a comprehensive approach see a cumulative effect on energy efficiency and realize a better return on their investment than those that upgrade a single, isolated building technology.
In the end, facilities that take a well-planned and integrated approach to controlling, managing and optimizing their power will find themselves with the tools to turn a costly utility expense into a competitive advantage.
Cassandra Quaintance is energy market segment manager for Schneider Electric’s North American Operating Division. She is responsible for defining the company marketing strategy for energy efficiency within the markets Schneider Electric serves in the U.S. Quaintance holds an MS degree in technology management from the University of Denver and a BS degree in mechanical engineering from the Colorado School of Mines.
Energy efficiency of power quality technologies
Dr. William (Bill) Brumsickle
Sr. Member, IEEE
Common goals for industrial plants are to increase productivity and reduce energy use. Over the last decade, plant engineers have come to understand that electric power quality has been a neglected process variable that explains much of their unscheduled downtime. Several power quality technologies are in use to improve productivity. But how these devices affect your energy bill is seldom considered.
The power quality issues that need fixing most are non-deterministic events such as voltage sags, and momentary interruptions caused by weather, animals and equipment failures on the utility grid. These events last only a few seconds and happen a few dozen times per year. They differ from minutes-long outages, which generally occur only every two to 10 years. Power quality events leave generators connected to the power grid, and generator power remains available %%MDASSML%% even though your voltage is reduced.
Power quality devices correct load voltage %%MDASSML%% either by boosting the utility voltage to the load, or by disconnecting from the utility and providing the load power from a stored energy source. In the first camp are constant voltage transformers (CVTs), dynamic voltage sag correctors and dynamic voltage restorers. In the second camp are Uninterruptible Power Supplies (UPSs). Power factor improvement devices and surge suppressors won’t help here.
Ferromagnetic transformers %%MDASSML%% also known as CVTs %%MDASSML%% work by continuously oscillating energy between the CVT’s transformer secondary and its load-side capacitor. Sloshing that energy back and forth creates heat. CVT efficiency is 70% to 80% in typical applications. CVTs are commonly installed with PLC panels, often in the hundreds or thousands. Taken together, they could burn a megawatt of wasted heat in a large plant.
The old favorite for power quality protection is the always-online, double-conversion UPS, with energy stored in batteries, rotating flywheels, superconductors or super capacitors. All energy storage has losses that must be recharged, as well as maintenance needs. But the online UPS has further losses through the double-conversion path. UPS efficiency is often less than 90% at full load %%MDASSML%% and gets much worse at light loads, as the Department of Energy has found. Lower energy efficiency means energy is lost as heat, warming the surrounding area. This often means that further cost and energy must be expended to remove waste heat.
Such losses are avoided in the newer dynamic sag correctors and restorers that use the utility grid itself to supply the correction power. These devices are normally in static bypass, with the line electronically connected to the load and correction circuits idled %%MDASSML%% a 98% to 99% efficient state. Only for those few seconds a year when correction is needed do these dynamic devices operate to boost the remaining utility voltage.
Across the country, these losses amount to hundreds of megawatts. Some utilities offer rebates on more efficient solutions. Power protection that reduces downtime without wasting energy is available, if you ask the right questions.
Dr. William (Bill) Brumsickle is the vice president of engineering at SoftSwitching Technologies and a senior member of IEEE.
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