Success Stories-How Submeters Reduce Energy Use & Lower Operating Costs.

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Submeters are helping facility personnel to succeed at using energy more efficiently and effectively toward the goal of lower operating costs. Engineering firms and others serving the facility sector can positively impact their own bottom lines through an appreciation of submeter functionality, capability and application. The following success stories illustrate how building professionals across the facility landscape are making that happen.

Since their introduction to the market in the early 1980s, submeters have grown dramatically in functionality and usefulness, providing great value to facility owners and operators as "front-line" energy data gathering tools in an era of rising utility costs and tightening budgets. Today submeters are coming out of the electrical room and into building lobbies and other public spaces to give users, tenants, employees and others visibility on actual energy usage and its impacts in terms of CO2 emissions, kWh dollars and other parameters easily understood by laymen.

Submeters are helping facility personnel to succeed at using energy more efficiently and effectively toward the goal of lower operating costs. Engineering firms and others serving the facility sector can positively impact their own bottom lines through an appreciation of submeter functionality, capability and application. The following success stories illustrate how building professionals across the facility landscape are making that happen.

Submeters at a Glance

The level of profiling needed by today's high-volume energy consumers is simply unobtainable using the standard utility meter found at the main electrical service entrance. That's why more facilities than ever are using submeters as first-level data-gathering tools to literally save thousands of dollars in reduced energy costs. As metering devices with monitoring capability, submeters are installed on the facility side of the master meter to provide any or all of the following:

  • Usage analysis and peak demand identification
  • Time-of-use metering of electricity, gas, water, steam, BTUs and other energy sources
  • Cost allocation for tenant billing
  • Measurement and Verification (M & V) and benchmarking for energy initiatives, including LEED Energy & Atmosphere (EA) and Water Efficiency (WE) credits
  • Load comparisons
  • Threshold alarming and notification
  • Multi-site load aggregation and real-time historical monitoring of energy consumption patterns for negotiating lower energy rates, and more.

Of the three main submeter types shown in the chart, the first two-feed-through and current transformer (CT)-based-are socket-type meters. CT-style socket meters are used with loads of 400A and above. In commercial applications, they may be specified but will take up a lot of space in the electrical room due to the need for CT cabinets and the meter bases. The extra space requirement cuts into the available rental space, which is undesirable in the commercial marketplace. Another major disadvantage in many jurisdictions-socket meters are not UL listed. The third type is the electronic submeter, a non-socket device that provides clear advantages over the previous two, as shown in the chart to the left.

Measurement & Verification

As noted, 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 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.
Key Role of Submeters in the Facility "Greening" Process

Manufacturers like E-Mon have responded to the "green challenge" by developing advanced hardware and software tools that specifically address the M&V needs of LEED v3 and other green building energy initiatives now dotting the facility landscape. Certified to ANSI C12.1 & C12.16 national accuracy standards, advanced E-Mon D-Mon submeters offer a number of important functions for new construction or retrofit applications, including:

  • Scrolling LCD display of kilowatt-hour (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 (BAS) communications
  • Optional integration with automatic meter reading (AMR) system for billing and analysis
  • Optional displays of energy usage and carbon footprint data via user-friendly meter dashboards accessible from standard web browsers
  • Compatibility with pulse-output utility meters, including electricity, water, gas, BTU, steam, etc.
Reducing Carbon Footprint

Department of Energy data reveals the average CO2 emissions 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 ejected into the atmosphere. So what can be done to reduce it?

Facilities can start by benchmarking how much CO2 they are generating. Metering technology has reached the point where users now have an easy way to see their own carbon footprint. These so-called "green submeters" come in sizes ranging from 100A to 3200A fro both 120/208V and 277/480V applications. Usually they can be installed anywhere and, because they use split-core current sensors to measure the equipment or circuits of interest, they are quickly and easily installed without powering down the load.

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 monitored. This eliminates having to power down the load and makes for a quicker, safer install.

Submeters are useful for raising awareness of both electrical consumption and carbon footprint. meters from E-Mon and other suppliers now come with rolling displays that show kilowatt-hours used, real-time kilowatt load, the estimated total amount of CO2 generated to provide electricity and the projected hourly CO2 emissions based on actual load. Another benefit that meters provide is to let users see their total electrical energy cost to date and their projected hourly cost based on actual load. Software automatically graphs CO2 emissions in parallel to demand (kW) figures, while also providing the data in tabular format where the peak CO2 load and the total CO2 emissions are displayed.

Submetering the Industrial Environment

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 submeters 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 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

An Alliance to Save Energy study reports that the connection between energy choices and cost is not always made. In the study's example, "compressed air leaks are often overlooked because 'air is free,' although this conclusion ignores the fact that five horsepower of electricity is consumed to generate one horsepower of compressed air. Steam system management is susceptible to similar thinking. Plant operators who assume that scrap rates are of no importance 'because scrap can be melted down and used again' are not considering the excess energy consumption that this practice requires."

Success Story - New Hampshire Foundry Submeters Energy Use, Avoids Plant Closure

A New Hampshire valve foundry was collocated with its sister division. Both divisions shared the combined energy costs, but one business unit was experiencing unusually high costs compared to other corporate facilities that manufactured the same products with similar equipment. As a result, the corporate office made preliminary plans to shut down the division and move the manufacturing operation to an area of the country with lower electrical tariffs. In an attempt to solve the problem without having to relocate the business, managers installed E-Mon D-Mon submeters to isolate the energy usage of the two divisions and to measure usage of specific equipment and processes.

Managers found that the division paying for 60 percent of the electricity bill was actually using less than 41 percent of the complex's total energy. The submeters also showed that a heat-treating process used once a week was causing a 175kW spike in energy usage. The division worked with the corporate accounting department to re-allocate its percentage of the energy bill and move its heat-treating process to a day when overall demand was lower. Thanks to submetering, the division saved $2,100 per month just by eliminating this spike in electricity, with the result that energy allocation was reduced by $324,000 per year and closure plans were cancelled.

Commercial and Multi-Tenant Facilities

Managers of multi-tenant facilities must keep tenants happy while showing the property owner that building efficiency, occupancy rates and profitability are all in line. Without submetering, building managers usually allocate energy costs and Common Area Management (CAM) charges to tenants on a cost-per-square-foot basis. In these situations, submeters and energy intelligence software can be installed to monitor actual electrical consumption by both tenants and common areas, track energy use and help facility managers analyze the data to identify areas for cost savings.

Beyond cost savings, the benefits of submeters and energy intelligence software include accurate allocation and increased tenant satisfaction. Building managers gain the ability to allocate and recoup costs based on actual usage, which helps tenants to control their own energy usage and costs. Providing solutions for tenants to control their utility costs helps keep them as satisfied, long term tenants.

Success Story - Electric Submeters Help Mountain Resort Save Energy, Cut Operating Costs

California's Mammoth Mountain Ski Area (MMSA) is one of the world's top resorts, hosting three large day lodges, 29 lifts, three gondolas, four hotels, three restaurants and scores of other 45,000-180,000 square foot buildings and structures spread over 3,200 acres.

As Mono County's leading power user, MMSA conscientiously tracks electrical consumption and demand to save and use energy more efficiently and to lower operating costs. To that end, MMSA installed an electrical submetering system from E-Mon to convert the RS-485 meter output to a 10Mbps data stream for download to the host computer via the facility's existing Ethernet backbone. This allows management to import the meter data into the E-Mon Energy automatic meter reading (AMR) software to create graphs and reports for charting energy usage/demand, cost allocation by tenant or department, billing or other functions.

The system has also shown its value for measuring and verifying energy savings and for identifying previously invisible conservation opportunities. Now in its eighth year of operation, system results have been very positive. "We now understand where, why and how much electricity is being used," said the energy manager, who pointed out that the real savings came from the ability to "drill down into the buildings to see what equipment is on and at what time, and to review the results from changes and additions to the building control system."

One of several submetered facilities at the resort, Canyon Lodge uses an E-Mon D-Mon Class 3000 submeter to monitor the facility's 480V, 1200A service. And results have been dramatic. "Over the last four years we've reduced the electrical costs in this 100,000 square-foot building by $72,000 per year, which we track with the E-Mon system." said the energy manager. The value of submeters in helping to conserve energy on the mountain is beyond question-overall electrical usage is down by more than nine percent, which at that scale of operation, translates to a substantial reduction in overhead cost.

Success Story - Luxury Condos Use Submeters To Allocate Electric Bills and Lower Energy Costs

Esplanade Place, a 12-story luxury condominium building overlooking downtown Phoenix, Arizona, provides the equivalent of four- and five-star hotel amenities to its residents. At the time of construction, E-Mon D-Mon advanced meters were installed in all 56 residential units to facilitate pro-rata energy cost allocation and monitor energy consumption in real-time on a daily basis.

To improve residential tenant billing for energy use, Esplanade facility managers installed CAT5 cabling to network the meters to a central computer from which billing could easily be managed, using E-Mon Energy, E-Mon's meter reading and energy analysis software. Three additional advanced meters were installed and monitored to improve access to energy use information for common areas, the pool and cooling towers.

Although there was no monitoring history for the common areas, the new meters, automatic meter reading (AMR) system and software made it very easy to se where and how much energy was being consumed in the various areas of the property. With this new information, some opportunities for conservation and cost savings were identified.

During the project, managers not only replaced hundreds of 60W incandescent bulbs in common areas, but also staggered the timing of the lights to reduce the amount of load placed on the electrical system at one time. In one two-day period during the summer, for example, facility managers watched as energy usage for the building dropped from 225 kWh to 135 kWh-a 40% reduction. The cost of energy for these common areas and amenities dropped dramatically from more than $1,000 per month to about $400.

Institutional & Government Users

The U.S. Department of Energy estimates a 20 percent savings when a building or energy manager becomes conscious of the facility's energy use through a monitoring device such as a submeter. The savings can be attributed to the manager allocating energy costs to tenants as well as identifying and eliminating areas of operational inefficiency.

Whether the facility is institutional, educational, healthcare or government-owned, a primary concern is identifying and allocating energy costs for various tenants, departments or users. In these settings, facilities can range from housing or administration buildings to food services and buildings with outside tenants. If submeters are already monitoring tenants' energy use, managers can utilize this existing equipment and install energy intelligence software to identify usage patterns and pinpoint possible inefficiencies, in addition to creating tenants' monthly bills.

Today's healthcare facility uses 2.7 times the energy of an equivalent-size office building. 24/7 operation and other unique needs make healthcare facilities ideal candidates for submetering to measure and verify compliance with energy management initiatives.

Compliance with EPACT 2005 and EISA 2007 regulations and green building initiatives are particularly challenging for government facilities as each complex is unique. Government facilities and complexes run the full range of building types including offices, single and multi-facility dwellings, plant/industrial facilities, medical buildings and educational centers. Key government sector submetering uses include:

  • EPACT/2005/EISA 2007 Compliance
  • Measurement & Verification (M & V)
  • Tenant Billing/Cost Allocation
  • Support Energy Reduction of 30%
  • Carbon Footprint Analysis

Drilling down, EPACT 2005 and EISA 2007 contain several requirements that are supported by submetering:

  • Section 102: Federal buildings must reduce energy use by 20% by 2015
  • Section 103: All federal buildings must be metered by 2012
  • Section 1251: Net Metering
  • Section 1331: Support for $1.80 Federal tax deduction
  • Provide equivalent metering of gas and steam by 2016

Leveraging the granular energy data provided by submeters allows government facilities to allocate actual costs back to users, tenants, cost centers or departments, analyze and verify usage reductions related to green building initiatives and support federal and local requirements for overall energy reduction.

Success Story-Energy Savings "Take Off" After Air Force Base Submeters Electrical

As the only active U.S. Air Force installation in the greater Los Angeles area, Los Angeles Air Force Base (LAAFB) in downtown El Segundo, California provides a sprawling, 150-acre expanse of R&D laboratories, government offices and other facilities at several area locations.

As one of the area's largest consumers of electrical power, LAAFB decided to install energy submeters behind the master electrical meter at the main service in order to obtain a clearer picture of how their energy dollars were being spent. The project involved installing 36 E-Mon D-Mon meters at the service entrances of 14 main buildings. Interval Data Recorders (IDR) were used to collect the raw meter data from the submeters and relay it to the energy manager's computer for analysis and reporting.

Less than three years after the E-Mon D-Mon submetering system was implemented at LAAFB, energy consumption decreased more than 27% from the previous year's established baseline. Utility costs decreased 23% from the established baseline during a period in which electricity rates actually increased by 4.5 percent. Overall Los Angeles Air Force Base is saving more than $1 million annually on its utilities, and is likely to save even more given the proliferation of energy initiatives impacting the government sector combined with steadily rising energy costs.

Energy Monitoring in the Educational Environment

Meanwhile in the education 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.

Despite tightening budgets, energy conservation and cost reduction are realistic goals that any K-12 facility, college or university can achieve using E-Mon's Green Class electric submeters. Designed for easy installation in new or retrofit applications, cost-effective Green Class meters are ideal for:

  • Event Allocation - energy usage of stadium and parking lighting, sound systems, vendors and more may be submetered to accurately allocate costs back to event sponsors
  • Leased Spaces - coffee shops, bookstores and other retail spaces use energy at different rates; Submeters are ideal for monitoring and generating accurate and fair energy statements based on individual use
  • Department Allocation - metering individual departments to include energy use is an effective way to increase energy awareness, lower usage and relieve department budgetary pressures
  • Student Housing - metering individual spaces increases energy responsibility through accountability
  • Equipment Maintenance - key items of equipment can be metered to profile energy usage, providing a diagnostic function that allows engineers to identify costly failures before they happen and to reduce downtime.

At the enterprise level, these devices can be used to assist in the development and verification of energy conservation initiatives, such as the U.S. Green Building Council's LEED Green Building Rating System that gives building owners and operators the tools they need to optimize building performance in a wide variety of parameters including energy management.

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 education quality.

Success Story - Submeters Verify Savings in College Energy Competition

CalPoly San Luis Obispo's "Green Campus Team" staged a five-week energy competition to see which residence unit at this central California college could save the most water, heat and electricity on a cost-per-student basis. To capture the energy parameters of interest in the nine-unit housing complex, Class 1000 E-Mon D-Mon electric submeters were installed in each building.

Submeter readings were taken three times per week, with usage data converted to an accurate cost-per-student figure. Deemed a resounding success, the energy competition that began in October 2009 resulted in a cost savings of almost $10,000 over the following five-week period. The competition measured a 15.7% reduction in total utility usage, which broke out to a savings of 14,619 gallons water, 117,325 MBTUs of heating and 76,874 kilowatt hours (kWh) of electrical consumption.

To track behavior patterns, CalPoly's Green Campus Team continues to read the E-Mon D-Mons after the competition ended. A follow-up survey revealed that 81% of residents altered their behavior to be more sustainable during the competition, and 78% said that they would continue to do so after the competition ended (by scannevin). Submetering itself may have a positive impact, since it has been demonstrated over the years that monitoring occupants' energy usage, in any facility setting, has a way of encouraging greater energy awareness and more sustainable behavior.

Dashboards Help Users Visualize Energy Reduction Measures

Submeters are useful for raising awareness of both electrical consumption and carbon footprint. Meters from E-Mon and other suppliers now come with rolling displays that show kilowatt-hours used, real-time kilowatt load, the estimated amount of CO2 generated to provide electricity and the projected hourly CO2 emissions based on actual load. Another benefit that meters provide is to let users see their total electrical energy cost to date and their projected hourly cost based on actual load. Software automatically graphs Co2 emissions in parallel to demand (kW) figures, while also providing the data in tabular format where the peak CO2 load and the total CO2 emissions are displayed.

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) sulphur 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 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 800A main distribution panel shown, the first dashboard displays the various metered parameters; the second 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 re-forestation needed to offset the panel's CO2 contribution!


The public and private-sector facility landscape is changing rapidly, driven by economic challenges and the need to save energy and cut operating costs. Engineering firms serving the building sector will see in the bewildering array of new energy initiatives opportunities for selling and installing the equipment that will help their customer meet the new requirements. Submeters are a perfect example of core equipment needed for the application. The old energy adage "you can't manage what you don't measure" is even more applicable in today's energy-conscious facility environment. It is also an extremely effective door-opener for any submetering sales pitch to your valued customer.

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