Increasingly companies today are finding energy savings opportunities based on submetering their facilities. Using this new visibility to current consumption, much of these savings are achieved through simple no-cost, behavior changes, i.e. turning off unneeded equipment. Submetering highlights that fact that these systems were running when they need not be.
Retailers, banks, groceries, and companies with multiple warehouses, buildings or stores require a submetering strategy to achieve additional energy savings beyond the traditional upgrades of lighting, motors, chillers and other systems.
What is submetering?
Submeters are physical metering devices that monitor electricity, gas, water, steam and other utilities. Utilities sell services and use utility grade meters to gather this information. Submeters mirror this data collection for companies that install them. Common applications monitor electricity usage and data are sent, typically every 15 minutes, to energy management software (sometimes through the building management system) for analysis. Using the analytic capability of the software, external consultants, vendors, on-staff personnel, or some combination identify savings opportunities.
A number of different companies such as Diehl, E-Mon and Rockwell Automation manufacture physical sensors, submeters and power monitors, and over a hundred companies sell energy management software.
A typical approach is to add a single submeter for each building or to the utility main meter. (A best practice is to use two submeters per building, one for electricity and one for HVAC, but this is not always cost justified.) More comprehensive submetering strategies deploy multiple submeters in a building and even hundreds for a large, complex manufacturing operation.
What are the benefits of submetering?
Traditional utility bill analysis uses information that is simply too dated (bills arrive 30 to 45 days after usage) and too aggregated (bills are for an entire month, not 15 minute interval). Submetering addresses this information gap, providing real-time, granular visibility of energy use that can be used to affect operations.
Submetering benefits include:
-Identification of unnecessary equipment running at night, off shift, or during the weekend
-Ability to get information back to operators and facility managers the same day and to provide operators with feedback the next day about implemented changes
-Comparison and benchmarking of usage across similar facilities (stores, warehouses, or buildings) and over time
-Detection of utility bill errors by comparing submeter usage with the actual utility bill
-Better management of electricity usage when a facility faces demand limited or peak usage pricing from the utility
Lessons from early adoptions
Early adopters of submetering have secured savings and now have a better view toward the benefits and costs of the projects. They also know where submetering doesn't work. Lessons include
-Be sure to budget for spare parts for submeters and for maintenance (do not believe vendor claims that physical meters are maintenance free)
-Budget for someone's time, on your staff or with a vendor, to analyze the data
-Document savings for senior management
-Do not rely on alarms, as facility engineers are inundated with alerts. Rather, use insights from submeter data analysis to identify specific, proposed work orders for investigation
-Use spot metering as a cost effective compliment to ongoing submetering
Companies seeking to take their energy management program to the next level need to evaluate submetering as part of their plan.
Learn about submetering at the Enterprise Smart Grid Conference, Nov 2nd
Attend this conference to hear case studies from Beacon Capital Partners (which has achieved LEED certification for over 18 million square feet of office space in its portfolio), Genzyme (which has facilities around the world), Harvard University (which operates dozens of buildings that are submetered), Staples, Boston Sand and Gravel, Datotel, and other firms that have implemented submetering.