Energy management: crunching the numbers
Reducing energy usage is an ongoing practice, requiring education and continuing efforts by everyone in the organization.
May 13, 2013
There are many paths toward reducing energy and utility usage at plants—some are obvious, but some are not and require the help of consultants and suppliers. Any energy strategy, however, will need to get everyone involved from top down and bottom up. Expecting day-to-day savings on energy and utility usage is not a one-time event based on an audit and follow-up fixes. It’s a practice that needs to be followed every day and must include senior management, operations, engineering, maintenance and all employees.
“The biggest problem in the industry is that the manufacturer does not know where energy is used and lost,” says Niels Andersen, Invensys vice president, manufacturing consulting. “WAGES+R [water, compressed air, gas, electric, steam, refrigeration] is generally looked on as a fixed cost and allocated as overhead when [the processor] receives the monthly bill.” Energy use varies on the products being made, and some losses are “completely insane,” such as leaking underground water pipes and compressors that run on the days when there is no production. The right place to start (even before doing an energy audit) is to install the appropriate instrumentation to monitor energy usage per unit produced, adds Andersen. “We call this energy intensity. The energy consumption information must be collected for the equipment that is used for production during the time when a specific product is produced.”
“GE has found that energy treasure hunts are good places to start when looking at the systemic energy losses that happen inside plants as they age,” says Katie Beissel, GE Intelligent Platforms global industry manager—food and beverage. “This is most effective when done as a team involving not only energy experts, but also HVAC, motor and other experts to lend their expertise to the audit providing the most holistic evaluation.” Companies should assemble an internal team with domain experts for a multiple-day review of the plant during its normal stages—rest, startup and normal running.
When a processor is ready to do an audit with the help of an outside consultant, consideration needs to be given to the type of audit. There are two main types of energy audits—high-level audits or feasibility studies that focus on identifying energy-savings opportunities throughout an entire facility or more focused “investment-grade” audits that drill into specific equipment or measures and provide detailed recommendations, according to Chris Covell, SmartWatt Energy president. Feasibility studies are a great first step because they can point facilities’ personnel in the right direction, ensuring they prioritize projects appropriately. Investment-grade audits are necessary once those projects have been identified and prioritized, and the processor has moved into an upgrade phase.
An energy audit should include an engineer with specific expertise in a given area, says Kevin Frantz, Stellar Refrigeration Contracting automation manager. For example, a refrigeration engineer should look at the machine room for optimization. An energy audit should always start with looking at utility bills for the last two to three years and identifying seasonal cyclic loads. Processors should scrutinize utility bills over these years and develop a spreadsheet as part of any baseline study.
“The auditor must know where the opportunities are to quantify and take advantage of them along with how to incorporate and implement a system to monitor, trend/record and control while not disturbing or impacting the operational process of the facility,” says Alex Daneman, Hench Control, Inc. president and CEO. The audit must take into account the refrigeration equipment and design; operational process and requirements; electrical and mechanical compatibility; and hardware and software functionality and capabilities, adds Daneman.
Some processors may already have an energy management system (EMS) in place, but that doesn’t mean it’s working up to snuff or doesn’t need to be checked. “Improper setup or installation of EMSs can also affect usage,” warns John Wallace, director of product management, Emerson Climate Technologies. “Modern EMSs can monitor operating conditions and automatically respond to changes in a manner that minimizes energy use.” If older EMSs have had their settings or parameters modified after installation, refrigeration, HVAC and lighting systems could be using more energy than necessary. Therefore, Wallace says a well-designed audit should ensure any EMS equipment settings are checked as well as some of the more obvious energy leaks.
Finding/tracking energy leaks
Energy can be lost in any number of ways. Geoffrey Clippinger, Siemens industry manager, lists a few in the following categories:
- Poorly maintained equipment
- Use of outdated equipment that performs at a lower level than current industry standards
- Poorly designed processes
- Processes operating at suboptimal settings
- Lost opportunities to recoup energy
- Lack of sufficient management practices and/or monitoring systems.
Energy leaks are ubiquitous and often not taken seriously. Consider the underground water pipe leak. It has a way of mushrooming into a bigger energy loss problem than it first seems. If the flow or pressure appears less at the user end, the natural thing to do is increase the pressure. So, more electrical energy is wasted pumping more water into the ground. If the processor is paying for water, that bill goes up and so does the sewage bill, if the sewage bill is based on incoming water used. Other than digging up the pipe, professionals may spot water leaks with sonic equipment. The use of flow meters at both ends also could certainly indicate if there is a leak.
Fortunately, gas and steam leaks are often easier to find. “Handheld IR thermometers and ultrasound devices that ‘listen’ to air or gas leaks are powerful tools when maintaining distribution systems for compressed gases and steam,” says Cassie Karas Zwart, global program manager, water and energy solutions, Sealed Air. “Leaks often go unnoticed and have traditionally not been a production priority. They are easy to identify.” Quantifying the value of leaks like this frequently has a sobering effect on the processor.
“One of the common losses is energy stored in water,” says Ryan Beat, SSOE Group, electrical engineering. Water heated to process temperatures (120°F or above) tends to get sent down the drain or put in a holding tank without much thought to the heat energy contained in the water. Also, notwithstanding defective steam traps, some processors overcompensate problems with increasing steam pressure to the point where relief valves send it into the atmosphere, which is a clear waste of energy. Balancing the thermal load and using excess steam to heat water for boiler feedwater and plant hot water systems help ensure the energy is used in the most efficient manner.
Beat points out some other energy-saving tips—some should be well known by now. In many instances, processors operate pumps and fans with no speed controls. But often, these devices do not need to be full-throttled and can be scaled back with variable frequency drives (VFDs), saving energy. Centralizing HVAC controls and monitoring conditions allow facilities to make forward-looking decisions regarding HVAC usage. Cutting back on outside air can cut expenses as well.
“Compressed air that is used for cleaning/equipment blowdown or electrical panel cooling is a constant source of energy loss at a facility,” adds Beat. “Leaky valves, pipes and regulators let valuable compressed air escape without providing any production value to a facility.”
Hardware: Get the big picture first
Getting the big picture first is probably the place to start, because hardware is already taking a snapshot of the utilities. “An approach I recommend is to go top down,” says Arun Sinha, Opto 22 director of business development. “Start with energy and power (and possibly gas and water) at the building or facility mains supply. Monitor this usage for some time, and study consumption and demand as related to macro parameters such as weather, occupancy, plant operations, baseline, etc. Even at this level, anomalies, problems and surprises will surface.” Then, make corrections and adjustments, most of which will be behavioral. From there, apply monitoring to subpanels, then to individual process machinery, manufacturing equipment and those devices associated with HVAC. After a period of monitoring, the next stage would be to implement some controls. The ideal type of equipment for this process is an appliance that can be deployed easily and inexpensively to monitor energy and power—and is fully compatible to exchange data with a traditional process control I/O system.
Energy in the form of heat can be monitored with RTDs and thermocouples, says SSOE’s Beat. The volume of the media that the energy is stored in (e.g., tank or vessel) must also be measured. A good way to accomplish this is with a flow meter. Wiring the temperature and flow to a data collection center or a PLC as 4-20 mA analog inputs provides valuable data.
While tracking flow, temperature and pressure is important, appliance-like devices can be used to monitor and calculate the key performance indicators (KPIs) that are relevant for the evaluation of the efficiency of different applications and processes, according to Kathrin Günther, Endress+Hauser global head of energy solutions. Some of these KPIs include the coefficient of performance of a cooling system, steam boiler efficiency or the efficiency of filters in a compressed air system. These devices provide real-time data visualization, display KPIs in several graphical formats and transfer data via digital outputs to various network architectures.
Appliances like energy meters provide an enormous wealth of energy data but are often underutilized. “Because the vast majority of these meters aren’t networked together—or to anything for that matter—most of this data vanishes into an un-actionable black hole,” says Robb Dussault, Schneider Electric offer manager for industrial energy management solutions. He suggests putting in visualization systems and networking these meters together (assuming they have network options) into an existing Ethernet network, which will provide a picture of energy usage at different points.
One area that contributes significantly to high electrical energy bills is demand. Many companies do not realize they have a demand charge or even what that is, although it may make up to 30 to 50 percent of their electricity bill, says Sinha. Reducing peak demand at least somewhat is typically fairly easy, and even a small reduction can significantly reduce costs.
Jake Nixon, process improvement & project engineer at Mission Produce, explains why his company implemented an automated demand-response system in its Oxnard facility to get control of peak demands (or events) from processing equipment. It wasn’t as though he hadn’t tried to improve energy usage by manual control methods. “I was certain we could control the necessary actions manually—until we actually tried it,” says Nixon. “It took too much time, and we couldn’t fine-tune adjustments. Since we weren’t willing to risk production, we had to find a better solution.”
The Spara Demand Manager system, supplied by Powerit Solutions, reduces energy costs by decreasing a facility’s peak demand, which lowers utility bill demand charges. The system uses timed measures to reduce peaks or shift them to non-peak rate hours. Nixon has seen up to a 33 percent decrease in Mission Produce’s energy bill even while production has increased. Mission was able to shed 500 kW for demand response and realized an ROI of 20 months. Spara DM was designed to integrate with existing monitoring and automation systems (like those from Opto 22 and Schneider Electric) to enable energy management controls and extend existing infrastructure.
Implementing a demand-response system, however, requires some homework. For example, will a process be compatible with demand management or when load shedding is needed? The process requires careful integration into the automation system to enable controlled shutdown and startup of processes when preset energy conditions are met, says Clippinger.
Tracking energy usage
Many packages are available to monitor energy usage. The key to selecting a package is choosing one that is scalable and low cost in its implementation and maintenance, suggests Beat. Bare-bones energy monitoring can be performed without the use of an energy monitoring package by using equipment already installed in a facility. For example, a PLC can take the energy content in BTUs per hour and then display it on an operator screen. The energy data can also be logged to a database for automatic recordkeeping and historical trending. Sending as much information as possible to the PLC makes it easier to spot areas of the plant that are not running efficiently. The PLC can take corrective action (e.g., cycling down equipment contributing to the problem or alerting an operator to make a decision) to alter the conditions that are causing a loss in efficiency. The ultimate goal, says Beat, is to have a fully automatic response, with the operator on hand to take manual control only when needed.
Basic functionality of EMS software, according to Günther, should include visualization and evaluation of process data, as well as energy analysis, cost analysis, reporting and deviation analysis. Energy and cost analysis should include all utility components (WAGES+R) and have the ability to do regression analysis. The software also should be able to do time-based comparisons, create budget plans and run profitability calculations.
More advanced systems provide the ability to sum multiple individual points and provide a “drill down view” (i.e., a graph that shows consumption for the complete plant and, with one click, can drill down to show a graph of the individual machines and how they contribute to the total energy consumption), according to Wallace. The systems also can provide the ability of incorporating external data (i.e., outside temperature or operating conditions) and normalize the energy consumption based on the data which can help identify drivers that affect energy consumption.
However, there is some discussion about the functionality of EMS software and its reach into process control systems. “Software—especially energy management dashboards—is a cornerstone of smart energy usage,” says Dussault. “That being said, it’s critical to make sure the software solution you implement is energy enabled. Although it is possible to take almost any SCADA or MES system and turn it into a sort of energy dashboard, don’t make this mistake. This could cost tons of hours of integration labor and enormous expenses in the form of software additions and expansions, as well as the risk of it not being compatible with future upgrades.”
“A dedicated energy management software package that focuses solely on meter reporting could be used,” says Michael Yammine, CTO/electrical engineer at Systems Group Technologies. “However, a complete automation suite consisting of HMI/SCADA, energy management, and fault detection and diagnostics functionality is better because it has the expanded benefit of not just recording aggregated use, but also correlating and displaying all process conditions that cause energy use. The ability to gain insight into the cause of energy use is critical to identifying opportunities for improvement.”
Automation systems can serve as a hub or repository of information that can be applied to energy management. “Automation system-based solutions, such as WinCC or PCS7, are strongly integrated with the automation of the plant,” says Clippinger. “Any measurement point within the system can be accessed as required for energy calculations. This can also be very advantageous where load management is a requirement.” IT-level or web-based systems (e.g., XHQ, Simatic IT MES or Win PM.Net) expand capabilities to interface with multiple systems besides EMSs and can offer enhanced reporting and management, but typically require more extensive integration efforts, according to Clippinger. This allows the dashboarding of KPIs, identification and financial quantification of loss opportunities, gap analysis, continuous improvement recommendations and other analytics across a multi-plant corporate system.
When a major North American brewer was confronted with rising energy costs, its six facilities with different ages and varying process control systems compounded the difficulty in determining how to cut the costs. There was only one advantage going for the brewer: It had GE’s Proficy Plant Applications software running in all six breweries, which provided a common platform for tracking recipe execution, key process parametric data and event data. By treating energy and water as elements of the bill-of-materials, the engineering team ensured all the conditions and events surrounding good or poor consumption profiles could be analyzed for opportunities to increase utility efficiency. Performing the analysis and subsequent tuning efforts with a complete production and quality tracking system ensured that energy reduction efforts didn’t compromise beer quality or flavor. The brewer has made significant strides in energy efficiency and cost, and is on pace to recover $10 million in energy costs over five years.
In the past several years, cloud-based “software as a service” (SaaS) energy monitoring software packages have emerged in the marketplace and may fit the needs for smaller and medium-size processors, according to Opto 22’s Sinha. A couple of examples are eSight Energy (www.esightenergy.com) and Pulse Energy (www.pulseenergy.com). These SaaS energy solutions have pre-built dashboards, analytics and easy-to-use reporting. “It is true, one could build these functions into a traditional process control HMI, but there would be time and effort associated with that,” says Sinha. “Further, at this point in time, my experience is that the energy discussion is often one that is occurring not with persons associated with the factory, process or plant floor, but with those persons responsible for financial aspects of the operation [P&L], sustainability, green initiatives, etc. The SaaS tools mentioned provide powerful information to these types of people, without requiring the specific technical skill set often associated with a traditional HMI.”
ERP and MES connections
The most important task for the energy management system is to convert WAGES use data from an overhead fixed cost to a variable cost assigned to each unit produced, according to Invensys’s Andersen. Only when manufacturers understand where energy is being consumed and wasted can they begin to reduce losses. It is obvious this information can be integrated into ERP systems to ensure the standard cost per unit planned and produced is understood. However, it does generally not make sense to create the EMS within the ERP system as the amount of data and the detail of information are beyond the scope of ERP systems.
With energy monitoring integrated with process control and ERP, a food and beverage processor can close the loop between the equipment and process level controls and the ERP system, including those from multiple vendors and disparate existing systems, says GE’s Beissel. By integrating the ERP production schedule with the plant systems, processors gain insight into actual production costs by line and product.
It’s important to remember that an EMS normally doesn’t actively control the processes within a plant, says Clippinger. But an EMS and MES provide the right home system for recording energy data; they maintain detailed information the ERP system doesn’t need. Energy usage information, however, may be fed to the ERP system for billing verification and cost allocation.
Like HMI and process control systems, some EMS software can communicate with ERP systems through databases and user-configurable web services, according to Bruce DeLong, ICONICS business development manager. “Critical to improving energy use is the reassignment of energy from an overhead cost to a cost of goods or cost of manufacturing.” Thus, besides calculating cost of energy per unit, an ERP could calculate the energy cost per customer order.
For multinational processors, the integration of EMS data within an ERP system can also provide visualization of KPIs on higher levels, such as benchmarking plants and lines located in different countries around the world, says Günther.
“Effectiveness is measured through continuous improvement,” says Clippinger. “The user will define and measure energy-related KPIs, which can include use ratios and peak load events, for example. When the user drives data contextualization by linking energy data and order-product-machine data, [he/she] begins to understand quickly the opportunities to improve and, therefore, reduce costs.” However, there is one important point. “If the improvement measures are not kept in place, the user will see KPIs start to slip. An effective EMS assists the user in identifying the cause for the KPI to slip,” adds Clippinger.
How could a KPI slip? Dussault provides an example: “A conveyor belt could be optimized to run at a specific speed for ultimate efficiency. Let’s say a crisis causes a worker to override this setting to speed up for production, with the full intention of returning the belt to its optimized setting. Now, if that person goes off-shift during the crisis, it is quite possible to forget this change, and the belt risks running on manual override for months. Though it may not seem like it would affect much, imagine dozens of belts in this scenario, as well as any other tinkered-with processes. Your workers might not notice, but your energy bill will.”
As noted before, to measure effectiveness, a baseline is needed—even if it involves a new building expansion project. Stellar completed the construction of Bahamas Food Services (BFS) refrigerated distribution center in Nassau, Bahamas, doubling the refrigerated space—adding 56,000 sq. ft. and two new temperature zones. Considering the warm climate, the expanded facility is expected to operate with the new addition at pre-expansion energy levels. The expansion features pallet storage racks and LED light fixtures for energy savings. To obtain baseline data to measure future results, the engineering team installed energy monitoring controls six months prior to construction start.
“Stellar was very proactive in suggesting ways we could save more energy,” says Phill Duncombe of BFS. “Our electric bill is a major portion of our operating costs, so finding cost-effective ways to save energy is incredibly valuable.” BFS operates a highly energy-intensive facility on an island where power averages 38 cents per kWh—compared to six to 11 cents in the US.
For more information:
Niels Andersen, Invensys, 508-543-8750, email@example.com
Katie Beissel, GE Intelligent Platforms, 800-433-2682, firstname.lastname@example.org
Kevin Frantz, Stellar Automation, 904-260-2900, email@example.com
Alex Daneman, Hench Control, Inc., 510-741-8100, firstname.lastname@example.org
Ryan Beat, SSOE Group, 419-255-3830, email@example.com
John Wallace, Emerson Climate Technologies, 770-313-3011, firstname.lastname@example.org
Cassie Karas Zwart, Sealed Air, 404-870-6807, email@example.com
Chris Covell, SmartWatt Energy, 518-406-5079, firstname.lastname@example.org
Geoffrey Clippinger, Siemens Industry, 678-469-2238, email@example.com
Arun Sinha, Opto 22, 951-695-3000, firstname.lastname@example.org
Kathrin Günther, Endress+Hauser, +49 361 309 0, email@example.com
Michael Yammine, Systems Group Technologies, 567-208-4334, firstname.lastname@example.org
Robb Dussault, Schneider Electric, email@example.com
Bruce DeLong, ICONICS, 508-543-8600, firstname.lastname@example.org
Paul Van Every, Powerit Solutions, 866-499-3030, email@example.com