Submetering for Real-World Energy Savings

Since the industry's first solid-state electronic kWh submeters were manufactured and marketed by E-Mon in the early 1980s, almost half a million E-Mon D-Mon submeters have been installed worldwide for a broad range of energy monitoring and management applications in skyscrapers, shopping centers, airports, factories, office buildings, apartment complexes, industrial, governmental and educational facilities.

Whether designed in or retrofitted, E-Mon D-Mon submeters and E-Mon Energy software systems provide a total energy profile that can shave significant dollars off the facility operating budget.

Monitoring Individual Electrical Usage

As a highly accurate and scalable way to gauge actual power consumption (kWh) and demand (kW), electric submeters provide an extremely cost-effective way to fairly and accurately profile and manage precious energy resources with a level of granularity unmatched by the master utility meter at the main electrical service entrance. Typical uses include:

• Cost allocation for tenant and departmental billing;
• Usage analysis and peak demand identification;
• Common Area Management;
• Interval data recording in 15- or 30-min time slices;
• Time-of-use metering of electricity, gas, water, steam, BTUs and other energy sources;
• Measurement, verification 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.

Advanced Metering Increases Value for the User

In the past, meter data was personally gathered by onsite "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 to drill down even deeper into the facility energy envelope in an attempt to get a handle on operating costs.

Manufacturers like E-Mon have responded to the challenge by introducing improved metering products with new communications options like wireless mesh networking and compatibility with Modbus, BACnet, LonWorks, IP and other protocols that continue to drive the technology toward greater sophistication and value for the user.

E-Mon's Green Class submeters provide a scrolling LCD display of CO2 emissions, kWh and other sophisticated energy measurements that can help users gain green facility certification points under the LEED rating system.

Submeters Drive Real-World Facility Savings

Submeters are making valuable, quantifiable contributions to bottom lines across the facility landscape. In San Francisco, for example, about half of the 52-story Bank of America Building was submetered after energy managers learned that tenants' 3kW/sq. ft. energy allowance was being exceeded by as much as 300%. More than 120 submeters were installed with the result that the assistant chief engineer estimated that the property owner was able to recover about $1M in excess energy usage in the first year of operation alone. He further stated that the cost of the submetering hardware and software in this application resulted in an ROI of days, not years, complemented by energy usage and cost savings of 30% per year. As a result of this experience, this leading nationwide property management company is evaluating submeters for its other properties around the country.

Another example, Los Angeles Air Force Base, is running 36 E-Mon D-Mon submeters in 14 buildings on the 150-acre base. As a result of submetering, the base energy manager estimates that energy consumption has decreased more than 27% from his earlier base line. Also, base utility expenses dropped 23% during a time when rates actually increased 4.5%. As a result of the energy manager's submetering-based conservation successes, he received the Air Force Materiel Command's Energy Award for that year.

In Washington, D.C., the Smithsonian Institution's Energy Management Group estimates that the 11 museum facilities in the Capitol Mall were able to bill back $1.7M of their 2003 energy costs to lease tenants that otherwise would have been paid with Federal tax dollars. The lead technician estimated that the figure would rise to $2M the following year due to rising utility rates and the opening of a new facility. According to this Energy Management Group technician, the $100K investment in metering hardware and software was paid for only three months after the first quarterly utility billing cycle.

Submetering the Bottom Line

Metering provides the raw material for energy profiling, but data collection is only the front end of the process. 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 practical value. For almost 30 years, E-Mon's full line of submetering hardware and software systems have helped facility owners and operators work smarter, not harder, to acquire, analyze and convert even the most sophisticated energy profile data into useful information for cutting costs, using precious energy resources more efficiently and improving the facility's bottom line.

The old energy adage - "you can't manage what you don't measure" - is particularly appropriate to today's energy-conscious facility and is also an extremely effective door-opener for any contractor desiring to promote the easily demonstrated benefits of submetering to his valued customers.