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Energy reporting is critical to connected lighting systems, for the simple reason that you can’t effectively manage what you can’t measure. One of the key reasons that electric utilities and energy service companies (ESCOs) have not invested more in lighting controls is uncertainty about the level of energy savings that will be achieved. To reduce that uncertainty, they sometimes resort to manual measurement and verification of lighting energy savings, which can push project costs much higher and even undermine cost-effectiveness. Data-driven energy management can significantly reduce energy consumption and enable new market opportunities, such as pay-for-performance energy efficiency initiatives; energy billing for devices currently under flat-rate tariffs; verified delivery of utility-incented energy transactions (e.g., peak and other demand response); lower-cost, more-accurate energy-savings validation for service-based business models; and self-characterization of available (i.e., marketable) “building energy services.”

If connected lighting products have the capability to self-measure and report energy use, they can reduce the cost of energy savings measurement. Utilities could offer incentives to customers based on actual savings instead of estimated savings, and ESCOs could recover payments from customers based on actual savings. Both ESCOs and utilities could offer a more convincing business case to their customers and incur substantially lower costs to collect and analyze energy use data from lighting control projects. The availability of energy use data from luminaires with integrated energy measurement and reporting capability creates opportunities for other energy-management processes. Further, the opportunity to facilitate and develop transactive energy markets with such data could be exploited. A variety of market actors may be interested, including building owners looking to realize the value of available — and perhaps marketable — building energy services.

TEST METHODS

DOE is utilizing its connected lighting test bed (CLTB) to develop test methods and setups for characterizing energy reporting accuracy. At present, DOE has completed a V1 device-level test method and setup and is working on a V1.5 minor update, as well as a V0 system-level test method and setup. The results of these efforts are currently being shared with appropriate industry consortia and standards development organizations, and a first use of the device-level test method and setup to characterize connected devices and connected lighting systems installed in the CLTB is under development. Industry stakeholders experienced in the development and use of such test setups and methods, and willing to provide DOE with feedback and/or suggestions for improvement, are encouraged to request access to the most current version by sending an email to DOE.SSL.UPDATES@ee.doe.gov with their contact information.

STUDIES

A first series of studies focus on power over Ethernet (PoE) connected lighting systems. These systems typically promise enhanced energy management capability, an important component of which is the accurate characterization of energy use.  However, it is often unclear which system component(s) are responsible for this characterization, making it difficult to evaluate the accuracy of energy use reporting and isolate sources of error. 

This first study describes and analyzes the various ways that PoE systems can be architected and report energy consumption. A follow-up study will test a variety of PoE connected lighting systems to evaluate energy use reporting accuracy and isolate sources of error.

A related study examines energy losses in PoE cabling, exploring the impact of cable characteristics and installation techniques, and verifying the usefulness of emerging industry recommended practices.

DOE is also currently working with prominent electric utilities to analyze the energy-reporting accuracy of outdoor lighting controllers. Many utilities bill for energy using a flat-rate tariff system and have difficulty vetting the accuracy of commercially available products — a challenge that’s exacerbated by the lack of dedicated industry standards and test procedures, and that further impedes utilities and municipalities from adopting more energy-saving connected lighting systems. DOE plans to compare the results from multiple test and measurement setups and offer recommendations for device manufacturers, test labs, and standards developers.

STANDARDS AND SPECIFICATIONS SUPPORT

In tandem with these efforts, DOE provides technical support for the ANSI C136–Standards for Roadway and Area Lighting Equipment committee, with a new focus on draft standards describing both energy reporting accuracy test setups and methods, as well as one or more classes of performance. Test and measurement experience is needed to drive the development of such standards. DOE is currently developing a test setup capable of characterizing energy reporting accuracy, with the intent of implementing draft test methods to characterize the performance of commercially available connected lighting devices that report energy consumption, and providing feedback to the ANSI C136 committee.

DOE also provides technical support and leadership for the Energy Prediction and Reporting working group in the recently formed ANSI C137–Standards for Lighting Systems committee, which is exploring the energy reporting needs for various existing and emerging use cases – including, for example, the support of electric utility pay-for-performance incentive programs and the validation of energy service company (ESCO) project objectives. As part of this effort, the ANSI committee has developed a survey to gather detailed information from users who might implement these use cases, in order to develop performance criteria that meet their needs. Use cases currently being explored include:

  1. Energy performance verification for contracted services
  2. Energy performance verification for utility energy efficiency programs
  3. System energy management (e.g., by a building energy or property manager)
  4. Indoor or outdoor electrical distribution system performance verification and/or predictive failure diagnosis
  5. Lighting device and/or system performance verification and/or failure diagnosis
  6. Energy performance verification for codes, standards, and certification programs (e.g., ASHRAE 90.1, ASHRAE 189.1, ASHRAE 100, IECC, LEED, California Title 20/24).

Energy data users who are interested in participating in the survey should send an email to DOE.SSL.UPDATES@ee.doe.gov with their contact information.