Today's commercial, institutional and industrial facilities are facing mounting pressure to operate more efficiently, cost-effectively and with less downtime. For this reason, automatic meter reading systems are gaining use for proactively managing energy demand and consumption, as well as diagnosing potentially serious problems before they happen. This white paper presents an overview of submetering for the green facility environment with an eye to how facility operators can improve their bottom lines through submeter-based cost allocation and other energy management strategies.
Building operators across the facility landscape are turning to advanced metering solutions to obtain the type of sophisticated energy data that the master utility meter at the main service entrance simply cannot provide. As first-level data gathering tools in the facility load-profiling process, submeters provide high-accuracy 15- or 30-minute snapshots of energy use (kWh) and demand (kW)-at the enterprise level all they way down to a specific circuit or item of equipment.
Submeters are an easily installed, versatile and scalable solution for obtaining the degree of energy intelligence granularity needed to optimize today's facility operations-no matter what type of facility is being monitored. Installed on the "facility side" of the traditional glass covered utility meter, submeters have proven themselves to be effective tools for monitoring, diagnosing and preventing bottom line-impacting problems associated with the facility's energy envelope. When combined with energy intelligence software, submeters provide insight on a building's flow and consumption of electricity. In today's increasingly cost-conscious commercial and institutional facility environment, obtaining such knowledge is more important than ever.
Energy intelligence software systems such as E-Mon Energy™ from E-Mon, generate energy usage graphs and profiles for demand analysis and power-reduction consideration in selectable 5-, 15-, 30- or 60-minute sampling rates. Itemized electrical bills for departmental allocation and usage verification are also easily created. Another useful function is determining the coincidental peak demand date and time for multiple facilities or loads. The software will read meters either on-site or off-site (via cellular or telephone modem, intranet, Internet and/or remote computers).
Role of Submeters in the Facility "Greening" Process
Submeter manufacturers like E-Mon have responded to the "green challenge" by developing next-generation hardware and software tools that specifically address the measurement and verification (M & V) needs of LEED v3 and other green building energy initiatives dominating the sustainable facility market. Certified to ANSI C12.1 & C12.16 national accuracy standards, advanced submeters typically offer a number of important functions for new construction or retrofit applications, including:
- Scrolling LCD display of kilowatt-hours (kWh) usage
- kWh in dollars
- Current demand load (kW)
- Cost per hour, based on current load
- Estimated CO2 emissions in pounds, based on DoE standards
- Estimated hourly CO2 emissions based on current load
- Net metering, including utility-delivered vs. user-received power and net usage
- Compatibility with BACnet, LonWorks, Modbus, Ethernet, RF and other popular building automation system communications
- Optionally integrate with automatic meter reading (AMR) system for billing and analysis
- Optionally view energy usage and carbon footprint data via easy-to-understand dashboards accessible from any standard web browser
- Compatibility with pulse-output utility meters, including water, gas, BTU, steam, etc.
Submetering Strategies for Energy Efficiency and Cost Reduction
A key advantage of the electronic submeter is its 0-2V split-core current sensor that is installed non-invasively around the electrical feed being metered. This eliminates having to power down the load and makes for a quicker, safer installation.
In today’s volatile energy market, there’s no shortage of reasons to submeter, and all of them are good. Following is a representative sample of typical energy management applications in which submetering and AMR software solutions are especially effective for optimizing energy usage and controlling costs, including:
Aggregation—the forming of a mutual interest group to negotiate lower power rates based on volume. Commercial property management companies, large multi-site industrial facilities, school districts and other volume energy users are likely candidates for aggregating energy use in deregulated jurisdictions.
Billing—providing revenue-grade accuracy, advanced submeters provide the raw data needed by property managers to provide complete, accurate accounts of submetered tenant spaces, common areas and other metered entities. Energy intelligence software seamlessly converts the raw meter data into user-defined billing statements that provide all the necessary detail to eliminate tenant disputes through fair and accurate billing of actual consumption.
Cost Allocation—individually metering common areas provides the data needed to recover and allocate these costs to event sponsors, tenants, departments or other budgetary entities. In the manufacturing setting, monitoring energy use of production, as well as non-production departments, allows businesses to drill down on to find how, when and where energy is being used.
Whether designed or retrofitted, submeters are installed on the "building side" of the main utility meter to measure energy usage from the enterprise level all the way down to a single device or circuit. Sold through distribution, today's submeters are easily interfaced with water, gas and other pulse-output utility meters to provide a total facility energy snapshot.
Submetering in the Educational Setting
In the educational setting, metering each department lets users take advantage of energy-saving opportunities which may be as simple as turning off lights or computers when rooms are not in use. When department budgets include energy use, users will be incentivized to reduce overall energy use. Monitoring energy usage of individual departments allows the tenant to allocate energy costs to specific departments within their own business, ensuring accurate budgeting and increased energy efficiency.
Demand Side Management—DSM consumer strategies are designed to reduce electrical demand and/or use. Factors involved in DSM include load management, load profiling and load shedding to shift usage and demand to off-peak periods. Utilities charge high demand (kW) rates for the entire month or longer, even if the demand only occurs once for a 15-30 minute period during that month. The key to avoiding higher charges is to identify usage peaks and take steps to reduce them.
Submeters can be used to profile individual or aggregated loads to pinpoint peak usage areas or equipment that is performing outside normal limits. This allows manufacturers to employ load controlling devices to set high/low thresholds, control loads and reduce energy costs. Large commercial and industrial users that purchase power by the hour using either forecast pricing or time-of-use (TOU) pricing will find TOU-capable meters and interval data recorders (IDR) of particular value for profiling demand and consumption at user-specified time intervals.
Net Metering—Net metering is an electricity policy designed for consumers operating small, renewable energy facilities, such as wind or solar power. Net metering gives the system operator a retail credit for at least a portion of the electricity that is generated and imported back onto the grid. Under EPAct 2005 Sec. 1251, all public electric utilities are required to make net metering available upon request to their customers. Typically of interest to larger industrial concerns with on-site cogeneration for example, net metering capability is available as an option to E-Mon’s Green Class Meter.
Measurement and Verification (M&V) —submeters are particularly useful in the facility M&V role. Since they may be installed virtually anywhere, submeters are ideal for monitoring individual items of equipment or circuits of interest. For example, individual submeters can be installed at the point of load to monitor chillers, HVAC, air handlers, pumps and so forth. Operational inefficiencies may thus be identified to reveal, for example, if two or more large loads are coming on at the same time, causing demand spikes.
Diagnostic functions also include the ability to identify equipment that may be close to failure, as indicated by a larger than normal current draw with no corresponding productivity output. Early identification of a potential problem allows facility engineers to schedule preventative maintenance before a costly failure occurs. Other key M&V capabilities enabled by submeters include:
- Load control options to automatically shed user-specified loads to avoid costly demand charges
- Tracking usage of lighting circuits before and after a retrofit to verify energy and dollar savings
- Verify a manufacturer’s stated efficiency claim on newly installed equipment
- Validate that the energy efficiency goals of building design are being met on an on-going basis for building commissioning and LEED certification
- “Shadow” the utility meter to provide a real-time snapshot of energy usage to allow budgeting for monthly energy charges before the utility bills for them
Submeters Facilitate LEED Certification for Health Care Facilities
According to industry estimates, overall facility operating costs are 10% higher than just five years ago, with combined utility costs up some 20% over the last two years alone. Interestingly, electrical usage during the latter period fell almost 13%, most likely in response to continuing rate hikes and other factors driving in-creased awareness and implementation of enterprise-level energy management systems (EEMS), equipment efficiency upgrades, utility energy initiatives and other cost-saving measures.
This trend especially impacts healthcare facilities which, according to the U.S. Energy Information Administration, use 2.7 times more energy than typical office buildings (Figure 4). Against this, overlay the DoE’s own analysis of energy use in the healthcare sector, in which $5.3 billion is spent every year, second only to the food service industry in terms of energy consumption.
Because of the energy requirements associated with supporting 24/7 operations and other unique needs, hospitals and other patient-care facilities clearly face a growing challenge in managing and controlling their energy use and demand without negatively impacting the quality and cost of their services. As a tool for measuring and verifying the facility’s energy footprint, submetering hardware and automatic meter reading (AMR) software systems offer an easily installed, readily available Rx for obtaining LEED certification points as shown in Table 1.
|LEED 2009 for Healthcare Submetering Chart
|Section Title & Credit
|Water Efficiency Credit 2
||Water Use Retention (M & V)
||Up to 2
||Provide for ongoing accountability of building water consumption over time.
|Energy & Atmosphere (EA) Prerequisite 1
||Fundamental Commissioning of Building Systems
||Verify project's energy-related systems are installed and calibrated according to project documentation.
|EA Prerequisite 2
||Minimum Energy Performance
||Establish building's minimum energy-efficiency level.
|EA Credit 1
||Optimize Energy Performance
||Up to 24
||Achieve higher energy-efficiency levels to reduce economic impact of higher energy use on environment.
|EA Credit 2
||Onsite Renewable Energy
||Up to 8
||Recognize increased levels of self-supplied on-site energy production reducing impacts of fossil fuel use.
|EA Credit 3
||Up to 2
||Begin commissioning process early in design phase, execute additional activities after performance verification is complete.
|EA Credit 5
||Measurement & Verification (M&V)
||Provide for on-going accountability of building energy consumption over time. Min 1 year post-occupancy.
|EA Credit 6
||Encourage development and use of grid-provided renewable energy sources on a net zero pollution basis.
|Regional Priority Credit 1
||Up to 4
||Provide an incentive for achieving credits that address geographically specific environmental priorities.
Energy Monitoring in the Educational Environment
To the energy management team at Kansas City's Rockhurst University, a key advantage of the E-Mon D-Mon submeter was its scrolling display that allows facility personnel to instantly verify that each building is operating within normal parameters. The submeter's profiling capability provides the energy data displayed by the building management system's energy monitoring software.
Meanwhile in the educational sector, rising costs, coupled with tighter operating budgets, are driving school facility managers to scrutinize their energy usage patterns, especially electricity which can account for up to 80 percent of the total energy costs of a facility. For this reason, many schools choose to submeter their electrical first, followed by gas, water, steam, BTUs or other utility services as budgets permit.
Once savings are realized, they typically remain in the facility budget to reinvest into additional energy savings programs and electrical upgrades. Growing numbers of institutions are discovering that, with the proper energy monitoring and management tools, operating costs can be effectively reduced—all without slashing programs, increasing tuition or cutting corners on educational quality.
As the data acquisition “front end” to the building management system, submeters can help schools identify savings opportunities that can help fund additional energy conservation measures or electrical upgrades. With educational facilities focusing more on energy and costs savings, monitoring of utility energy data and integrating it into the facility’s building management system is moving towards becoming a requirement rather than an option. The question then becomes: How can facility professionals meet this challenge in an era of tightening budgets and rising energy costs?
One answer is low-cost energy metering, which allows facility managers to profile energy usage in terms of con-sump ti on (kilowatt-hours or kWh) and demand (kilowatts or kW), as a first step in placing it under their control. Operating under the assumption that “you can’t save what you don't measure,” facilities around the country are turning to submeters as first-level data gathering tools to help them identify previously invisible savings opportunities.
Guidance for Electric Metering in Federal Buildings
The DOE’s Federal Energy Management Program (FEMP) conducted a number of metering workshops in the 2003-2005 time frame to help agencies understand and comply with the emerging federal guidelines. The results of those workshops were published in early 2006 as DOE/EE-0312, “Guidance for Electric Metering in Federal Buildings.” As the name suggests, DOE/EE-0312 is not a mandatory policy guideline, rather it provides a useful set of “serving suggestions” to help Federal facility managers design their own procedures and programs for complying with EPAct 2005. The 22-page document’s Executive Summary states up front that Section 103 of EPAct 2005 pertains to electric metering only and further defines what is meant by such terms as “buildings” and “maximum extent practicable.”
DOE/EE-0312 also provides implementation timelines and useful appendices, including (1) a glossary of advanced metering terms and (2) the full text of Section 103: Energy Use Measurement and Accountability of EPAct 2005’s Federal Metering Requirements. Downloadable from the Internet at no charge, readers are encouraged to obtain a copy of DOE/EE-0312 for more details relative to:
- Definition of “Advanced Metering”
- Uses of Metered Data
- Metering Approaches and Technologies
- Metering Cost-Effectiveness
- Methods for Prioritizing Buildings for Metering Applications
- Methods of Financing
- Template for an Agency Metering Plan
- Performance Measures
- Site-Specific Factors and Other Considerations
Predictive Maintenance in the Industrial Environment
Extremely compact, advanced submeters are easily installed in virtually any desired location to monitor kW, kWh and a number of other parameters by department, product line or other circuit of interest.
Plant operators require accurate, real-time status feedback to evaluate the performance of pumps, compressors, heaters, chillers, conveyors and other electrically powered equipment. By installing energy intelligence software, managers now have insight into deteriorating or problematic equipment when a particular load increases more than normal. Other benefits for plant managers include accurate allocation of energy for product runs, production lines of equipment or departments.
Submeters provide plant managers with vital data on energy usage, power quality and peaks, or shifts in power supply, that can help them address these power trends with their utility provider. With regard to internal plant operations, submeter data can also be used for tracking and allocating energy consumption costs across departments and/or manufacturing lines.
Unfortunately, many plant operators only gain insight into their energy usage after a head-turning event, when consumption has increased or decreased during the month based on ebbs and flows in production. The Enterprise Energy Management System (EEMS) ties all of a facility’s energy usage data together, providing manufacturers with the details of their daily energy usage. Where making products is the first priority, saving money can be an easy second by employing sub-meters to:
- Chart energy usage
- Compare energy usage by day, week, month or year
- Monitor all utility services, including electricity, gas, water and steam
- Schedule energy data collections to occur automatically
- Evaluate, in real-time, the impact of critical load-shedding activities
- Determine specific processes that are not energy-efficient
- Identify poor performers by benchmarking energy levels at multiple facilities
Integrating Meters into Building Automation Systems
First introduced in 1987, the Building Automation and Control Network, or BACnet, has evolved into ANSI / ASHRAE Standard 135-1995. Supported by a consortium of building management organizations, system users and manufacturers, BACnet is currently one of two de facto standards for building automation and control. LonWorks, the other leading open-protocol industrial networking platform, enjoys an installed base of more than 60 million devices since the technology’s introduction in the 1980s. According to industry sources, LonWorks and BACnet share an approximately equal 40 percent share of total available market (TAM), with the remaining 20 percent of the building automation system market being made up of other protocols.
Submeter manufacturers like E-Mon have responded to these proliferating building automation system protocols by introducing low-cost interface devices that convert electrical submeter pulse-outputs into communications formats compatible with BACnet, LonWorks and others. E-Mon’s Class 5000 meter equipped with Option B, for example, converts up to 38 metering data parameters into the BACnet Master-Slave/Token-Passing (MS/TP) protocol, providing measurements such as:
- Energy and reactive energy, delivered and received (kWh)
- Real power (kW), total and by phase
- Reactive (kVAR) and apparent (kVA) power, total and by phase
- Power factor (percent), total and by phase
- Current (A), voltage (V) and phase angle (degrees) by phase
Such communications capability greatly extends the submeter’s value for building automation and controls applications by enabling input of an expanded range of electrical measurements into the facility’s measurement and control system. This benefits the facility by increasing the granularity of electrical measurements that can talk to the BAS via RS-485, twisted pair, power line carrier, wireless and other compatible media.
Other types of interfaces are available to extend wireless capability to the facility sector’s large installed base of legacy submeters, as well as gas and water for any multi-tenant residential, industrial, commercial or institutional metering application. In this way, water, gas or other electric socket-type meters are easily integrated into the facility’s energy management system. Equally suitable for new or retrofit installations, new wireless meter products provide an inexpensive path to monitor any commercial or industrial property using a complete, two-way wireless communication system with interval data collection. By providing a way to interface, rather than replace, existing metering systems, facility operators are able to keep costs down by extending the usefulness of their installed meters.
Carbon Footprint Reduction
Department of Energy data reveals the average CO2 emission in the United States to be 1.37 pounds for every kilowatt-hour (kWh) of electricity generated. This takes into consideration all forms of generation from nuclear to coal-fired plants. To put it in everyday terms, using ten 100W electric light bulbs for one hour will cause 1.37 pounds of CO2 to be injected into the atmosphere.
In response, Internet-enabled energy monitoring and data presentment dashboards are gaining traction in the facility environment for displaying kWh, kW, peak demand, power factor and other energy measurements in real time, and historically, while also displaying the facility’s “carbon footprint.” This allows facility occupants to monitor their building’s carbon dioxide (CO2), sulfur dioxide (SO2) and nitrous oxide (NOx) emissions—while at the same time observing estimated energy conservation measures needed to compensate for the displayed levels.
The following screen captures below illustrate the sheer depth of energy information provided by a single submeter, in this case an E-Mon D-Mon Class 3000 device. For the 800 Amp main distribution panel shown below, the first meter dashboard displays the various metered parameters; the second dashboard shows the rest of the graph at the bottom of screen one, and the third dashboard displays the carbon footprint of the metered 800A panel over time, even extrapolating the data to an estimation of equivalent automobile miles driven and the amount of reforestation needed to offset the panel’s CO2 contribution!
By importing data from electric submeters and other metering devices into Web-based communications (Figure 8a-b), interval data may be cost-effectively collected, analyzed and displayed in near real-time to allow facility managers to shed load and perform other peak-shaving actions to lower their demand charges. Meter dashboards often include:
- Automobile-style gauges showing how power, fuel, energy budgets are being consumed on a real-time basis
- 24-hour load profiles for power, chilled water, steam or other building systems
- Historical comparisons of current usage versus previous time periods under similar conditions (time, day of week, temperature)
- Automated carbon foot-print calculations
- Tenant- or consumer-level information about energy use and efficiency efforts
Internet based meter dashboards like E-Mon's Web-Mon allow users to automatically integrate their distributed metering infrastructure into real-time meter dashboards via open-architecture Modbus IP-compatible LAN/WANs. Dashboards are available for single-facility (above) as well as multi-facility campus-style applications (below) to provide real-time and historical presentment of electricity, gas, water, steam BTU and other metered parameters.
Accurate, timely snapshots of energy usage and carbon footprint data are essential for supporting progressive energy management and green building initiatives. Meter dashboards like E-Mon’s Web-Mon are designed to provide users with a user-friendly web interface that allows them to view live energy data, charts and graphs via any standard internet Web browser without unnecessary features or costly custom programming. A built-in website right out of the box, Web-Mon requires no add-on software or programming to provide a “dashboard” display of various energy parameters of up to 24 meter inputs. Real-time meter data is displayed alongside historic readings from the previous seven, 30 and 365 days.
Can’t Manage What You Don’t Measure
Rising operating costs, coupled with tighter budgets, are driving facility operators to scrutinize energy consumption as never before. The type of energy data needed by today’s sophisticated facility manager is well beyond the capability of the master utility meter at the main service entrance. Utility meters provide a broad indication of consumption and demand, but true load profiling requires specific measurements taken at specified intervals to isolate the causes of load peaks—as a first step to eliminating them or moving them to off-peak hours when rates are lower.
As first-level data gathering tools in the facility load profiling process, submeters provide high-accuracy 15- or 30-minute snapshots of energy use and demand from the enterprise level all the way down to a specific circuit or item of equipment. Metering provides the raw material to manage energy, but data collection is only the beginning. Until the raw data is imported into software and manipulated for cost allocation, billing, load shedding, rate negotiations and a host of other uses, it has limited value.
Submetering hardware and software systems from E-Mon and others are designed to acquire, analyze and convert even the most sophisticated energy profile data into information you can use to save energy, allocate costs, use precious energy resources more efficiently and improve your facility’s bottom line.
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