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Submeters Facilitate Green Building Sustainability

Dec. 1, 2007
Recent industry studies show that green buildings will become a pervasive corporate trend within the next three years, and that over 60 percent of people

Recent industry studies show that “green buildings” will become a pervasive corporate trend within the next three years, and that over 60 percent of people surveyed already agree that green buildings do in fact lower facility operating costs. Late last year, the Building Owners and Managers Association (BOMA) and the U.S. Green Building Council signed a memorandum of intent to jointly “promote energy efficiency and environmentally responsible building operations and maintenance practices.” Add to this the EPACT 2005 mandate that all 500,000 Federal buildings must be metered or submetered by 2012, and it becomes even more obvious that tightening budgets, rising power costs and other operational issues have made energy resource management more important than ever for commercial building owners and operators.

Unfortunately, the level of profiling needed by 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. First introduced in the early 1980s, submeters are metering devices with monitoring capability that 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, verification and benchmarking for energy initiatives;

  • Load comparisons;

  • Threshold alarming and notification;

  • Multi-site load aggregation and real-time historical monitoring of energy consumption patterns for negotiating lower energy rates.

Submeters at a Glance

Of the three main submeter types shown in Table 1, the first two, feed-through and current transformer-based, are socket-style meters. The third type is the electronic submeter, a non-socket device that provides clear advantages over the previous two, as shown in Table 1.

Advanced Metering

Submeter manufacturers have responded to the need for more sophisticated energy profiles by developing products with advanced meter functions that far exceed the capability of the standard utility meter. Used in conjunction with automatic meter reading (AMR) software, submetering systems provide accurate and timely snapshots of a facility's energy use — from a single circuit or device all the way up to an entire building and beyond. Essential to support energy management initiatives, submeter-based AMR systems combine all of the facility's utility service data — including electric, gas, water and steam — into a single location to show — through a variety of communications options — how, when and where the facility is using energy.

In the past, meter data was personally gathered by on-site “sneaker reads.” Later, telephone modems greatly improved cost-efficiency and throughput. This was followed by sending data via Ethernet, wireless (RF) link, satellite, power line carrier (PLC) and other technologies. All of these methods are still in use to some extent. However, the data itself is more complex, and is now being used for load profiling, power quality monitoring, equipment diagnostics and a host of other functions. The availability of improved metering products with new communications options like wireless mesh networking and compatibility with Modbus, BACnet, LonWorks, IP and other protocols, continues to drive the technology toward greater sophistication and value for the user.

Submeters Take the Green Challenge

Building “green” generally refers to the practice of optimizing building efficiency by using less energy, water and materials, and by reducing the impact of buildings on health and the environment through better design, construction, operation, maintenance and other performance criteria over the building's life cycle. The terms “sustainable development” and “sustainability” are often mentioned in the context of green buildings, which are scored by a number of available benchmarking tools — the most widely accepted of which is the U.S. Green Building Council's Leadership in Energy & Environmental Design (LEED) rating system.

Building commissioning and LEED certification are based on accurate and reliable energy data. Submeter manufacturers have responded to the green challenge by developing next-generation hardware and software tools that specifically address the needs of the sustainability market by providing functionality that helps the using facility measure and verify compliance with LEED, EPACT, Renewable Energy, Demand Response and other major energy initiatives. Typical functions will include:

  • Scrolling LCD display of kilowatt (kWh) usage;

  • kWh in dollars;

  • Current demand load (kW);

  • Cost per hour, based on current load;

  • Estimated CO2 emissions in pounds, based on Department of Energy (DOE) standards;

  • Estimated hourly CO2 emissions based on current load;

  • Net metering, including utility-delivered vs. user-received power and net usage;

How Submeters Facilitate Green Buildings

Submeters can contribute directly to the certification of facilities under major energy initiative guidelines, including the Energy Policy Act of 2005 (EPACT) and LEED (Table 2). Specific compliance includes:

  • EPACT Section 103 — All Federal buildings must be metered by 2012

  • EPACT Section 1251 — Net Metering

  • EPACT Section 1331 — Support for $1.80 per square foot tax deduction

Distributor Sales Opportunities

As the primary electrical equipment supplier, growing green building construction — new and retrofit — provides a clear opportunity for the wholesaler to become an integral part of the process. Becoming knowledgeable about sustainable facilities, obtaining LEED accreditation, offering educational seminars and other measures, are only a few of the creative ways that distributors can differentiate themselves from the competition while providing real value to their customers. As word gets around that a certain distributor is “green savvy,” that wholesaler becomes the “go-to guy” for green building advice and equipment purchases.

Green knowledge provides a leg up in other ways, too. For example, the next time a contractor comes in to buy some energy-efficient T8 lighting, the green-savvy distributor may see an opportunity to also pitch submeters as a way for the contractor to get a few extra points toward that facility LEED rating or energy credit. The writing is on the wall — the world is going green. And submetering is just the ticket for sharing a little more of that “green” with the wholesaler's own bottom line.

Don Millstein is president and CEO of E-Mon, LLC, a leading manufacturer of electric submetering equipment, energy management software and services based in Langhorne, Pa. A member of the U.S. Green Building Council, the Alliance to Save Energy and the Federal Energy Management Program task force, Don can be reached at (215) 752-0601 or [email protected]. Web site:

Table 1. Non-socket-type electronic submeters are less expensive initially, quicker and easier to install and offer superior performance and options compared to other types.SpecificationsSubmeter TypeSocket Type Electromechanical/Solid StateElectronic Non-socketFeed-thru Current Transformer InstallationInstalled Cost (estimated) Stand alone, up to 320A, 3Ø $1,000 Not available $700 Stand alone, over 320A, 3Ø Not available $2,000-$5,000 $800 8-Meter Unit, 200A, 3Ø $16,000 Not available $5,500 Installation Time 2-3 hours 6-8 hours 1 hour Power Interruption 2-3 hours 6-8 hours None Amperage Limitation 320 Amp, Max. None None Space Requirements 2 square ft. 11.7 square ft. 0.25 square ft. Installation Location Utility room Utility room Anywhere FeaturesMultiple Meter Units (MMU) Yes Yes Yes Size of 8-Unit Cabinet 18.1 square feet 18.1 square feet 2 square feet Digital Readouts Optional/Yes Optional/Yes Standard Reset Capabilities No/Yes No/Yes Standard Multiple Load Monitoring No No Yes Subtractive Load Monitoring No No Yes Monitor Specific In-Panel Circuits No No Yes Amperage Modification in Field No w/CT change Yes Meter UL listed No No Yes EnhancementsDigital-to-Analog Profiles Yes Yes Yes Pulse Outputs Yes Yes Yes Timed Meeting Yes Yes Yes Software Monitoring Yes Yes Yes Upgradeable in the Field No No Yes Power Quality Functions Available Available Yes Net-Metering Capability Yes Yes Yes Form C Control Relay Output No No Yes Source: E-Mon, LLC Table 2. Submeters contribute directly toward points under several LEED green building certification categories.LEED Certification Category Credit Certification Points Applicable Energy & Atmosphere (EA) Guideline Core & Shell EA Credit 5.1 1 Measurement & Verification — Base Building Core & Shell EA Credit 5.2 1 Measurement & Verification — Tenant Submetering Existing Buildings EA Credits 3.3 1 Building Operations & Maintenance Existing Buildings EA Credit 5.1-5.3 1-3 Performance Measurement: Enhanced Metring Existing Buildings EA Credit 6 1 Documenting Sustainable Building Cost New Construction EA Prerequisite 2 — Minimum Energy Performance New Construction EA Credit 5 1 Measurement & Verification Commercial Interiors EA Credits 1 1 Optimize Energy Performance Commercial Interiors EA Credits 3 2 Energy Use, Measurement & Payment Accountability

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