E-Mon White Paper

The myriad of commercial and public-sector energy policies, while at times complicated,provides fertile ground for submeters as energy profilers and program verification tools.This white paper briefly overviews the main policies now in effect, with an eye to their potential for submeter usage.

In response to rising energy costs and tightening budgets, the last few years have seen a raft of new public and private-sector energy policy initiatives designed to micro-manage existing resources, reduce greenhouse gases and encourage, whenever possible, the move toward renewable, non-fossil fuel energy sources. Although similarities exist in many of these programs, the common thread in all of them is the clear need for advanced submetering hardware and automatic meter reading (AMR) software solutions to cost-effectively benchmark, measure and verify compliance with whatever program guidelines the facility is pursuing.

Submeters at a Glance

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, 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 below, 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 below.

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