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SMART UTILITIES: COMMONWEALTH EDISON Leading and Driving the Industry with Best Practices


By John D. Villani, PE, CCP, CEM, LEED AP
Grumman/Butkus Associates

In an era of overstated energy savings and green-washing energy project results, here is one service provider’s retro-commissioning perspective on a true industry leading energy savings program. For the past decade, Commonwealth Edison (ComEd) has been driving and pushing the energy efficiency industry to deliver verified energy savings through a portfolio of energy savings programs and offerings.  Over this time we have seen the programs grow and respond to Owners’ and industry needs, becoming more stringent and robust to deliver data-driven “real” verified energy savings.

Best Practices. ComEd runs one of (if not the) strongest retro-commissioning (RCx) programs in the country.  The program typically funds the entire retro-commissioning service provider’s fee from planning through verification.  This makes for a very easy win with Owners and service providers.  The program is simply structured to only ask the Owner to commit to fixing the issues that are found and scoped through the RCx program.

Keeping it real. ComEd requires Owners to spend a certain amount of money on repairs and upgrades that are identified through the RCx process.  From our experience, we have found that clients are very engaged in the process; we find energy savings opportunities that will cost more than 3 times the ComEd minimum spend commitment amount, AND that Owners typically spend double the prescribed minimum spend amount.  For large facilities, 400,000 Sq.Ft and up, this typically translates to Owners spending $50,000 to $60,000 on repairs and improvements that deliver a simple payback of less than 1.5 years.  From our [Grumman/Butkus] RCx project tracking analysis for participating in the ComEd program, we have compiled the following data:

  • # of projects completed = 43
  • Average building size = 742,210 Sq.Ft.
  • Average kWh Saved = 722,710 kWh
  • Average % kWh Saved (from entire bill) = 5.7%
  • Average Therms Saved = 48,180 Therms
  • % Therms Saved (from entire bill) = 7.3%

Verified RCx energy savings is an essential part of the program.  ComEd’s program manager, Nexant, provides technical and energy engineering reviews throughout the entire RCx process.  Nexant’s work includes reviewing the two-week minimum pre and post measure implementation trending data to confirm the actual data and results.  Navigant, the utility commission’s third party independent verifier, conducts a second level of review. This level of scrutiny is beneficial across all projects and service providers since lessons learned from each project and how savings are calculated can be shared.  Navigant also conducts an energy engineering review of selected projects’ verification reports.  All this scrutiny assures both the Owners and utility that the savings are real, and it’s a great feedback mechanism to the providers of what really works to drive savings results.

Energy Savings Strategies: A Favorite Story

Here’s a favorite story from a Navigant third party review and the depth and detail of analysis on these projects. On a healthcare project with very large air handling units ranging from 60,000 to 100,000 cfm, we deployed two significant energy savings strategies: (1) discharge air temperature (DAT) reset AND (2) static pressure reset based on heating and cooling terminal box demand.  Navigant appropriately picked up that these two measures will fight each other and that as you raise the DAT more air will be required to satisfy the space cooling loads.  However, in our verification report we were not claiming this and were showing both an increased DAT setpoint AND reduced operating static pressures.  The reviewer disagreed with our savings and said this was not possible.

Keeping it real: When we reviewed this with Navigant our first question was, “how many months of data do you want?”  We have been trending the DAT and static pressure for these systems since the start of the project.  What we found was this: these systems were both delivering overcooled air AND running at too high a static pressure (typically around 6” of static pressure).  The terminal VAV boxes were compensating by having mostly closed damper positions and utilizing reheat to meet the space setpoints.  We also attribute the system’s ability to operate satisfactorily at lower static pressures to the high-rise building’s 30-year-old HVAC systems having significant duct leakage throughout the very large main duct risers and distribution ductwork.  After static pressure reset was deployed, we found most systems operated at a reduced static pressure of around 4.5”.  We were also able to raise the DAT from 2 to 5 degrees most of the cooling season.

The end of the story is that while Navigant correctly identified two measures that typically fight each other, through the robust RCx program ComEd runs, we (the service provider) were able to have the engineering time to apply in-depth trending and verification methodology which was then used to demonstrate to Navigant the proof of real energy savings.

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