CLTC - ALCS Bench Testing - System Self Energy Metering

Advanced Lighting Control System (ALCS) Bench Testing Phase II aims to revisit and refine the technology validation program developed in Phase I. The goal of this study is to assess whether current commercially-available ALCS can accurately report connected load energy use consistent with current utility requirements, such as revenue-grade labeling. If ALCS could replace expensive third-party metering equipment, and utilities pursued a pay-per-performance measure, the availability and use of energy consumption information could save an average of 2 – 5% over the system's life, based conservatively on an American Council for an Energy-Efficient Economy (ACEEE) meta review of energy-saving technologies. In addition, energy use information obtained via ALCS could be monetized in various research and development and ET projects, or utility programs. Phase II found the most promising lighting systems with energy monitoring capabilities, and tested them under various conditions influenced by today’s prevalent lighting technology. The project team conducted a market assessment, refined and expanded on the test methodology proposed in Phase I, and tested three ALCS and one revenue-grade system. The research team found System 1 was the most accurate device of the three ALCS, with an average error of 2.31% in the relevant tests. For System 1, we tested three individual load controllers with energy monitoring, and there was good agreement among the units in nearly all the tests. System 1 was the most user friendly for recording and extracting energy use data. In 75% of the tests, System 2 was more accurate than System 1, but it failed to consistently record data in higher amperage tests across acquired units. Due to a loging error, multiple tests conducted near the three units’ maximum current range had a chance of failure. The resulting reported value would have been significantly lower than the expected value. This error occurred on multiple units, and repeatedly occurred on retests for select units, making the system inconsistent. These errors caused the system to have an average percent error of 8.56% across all three units. In addition, System 2 was the most challenging to record and extract energy use information, because a Building Management System (BMS) was necessary, along with extensive code work. Finally, System 3 performed the worst, and failed to meet the manufacturer’s accuracy claims in 95% of test scenarios. Measured values were well over the reference values, and consistency between the two acquired units was low. Technicians could not find fault in installation or commissioning; however, System 3 offered a straightforward recording and extraction process, although it requires an SQL database set up on a dedicated computer. When testing the revenue-grade system under a subset of test conditions, the system performed better than all three ALCS systems. The revenue-grade meter did not struggle with complex lighting-specific waveforms, and accuracy between waveforms was maintained more consistently compared to the ALCS systems. The tests averaged a 0.43% error, with a standard deviation of 0.0002 across waveforms. In contrast, System 2 resulted in an average error of 0.77% and a standard deviation of 0.0046, under the same conditions. Testing determined the three ALCS all performed worse than a revenue-grade meter. However, some ALCS-integrated meters proved consistent among devices, and some could presumably meet a sub-2% error when compared to a reference, if improvements were made to the device software.  Integrated ALCS solutions are more straightforward than revenue-grade systems and lighting controllers. ALCS systems also offered more integrated controls and data displays than the revenue-grade system, and were easier to integrate with BMS or other control systems. With respect to cost, buying and installing an ALCS load controller with an integrated meter is significantly less expensive than purchasing and installing a revenue-grade meter. Additional costs associated with upgrading a lighting controller to ALCS-integrated meter products range from $50-$100 based on selected systems, while revenue-grade systems cost around $300-$800. Based on per-circuit metering needs, ALCS-integrated meters are 57.2% to 82.4% less expensive than revenue-grade meters. CLTC believes it is feasible to implement various pay-per-performance measures centered on the use of energy data recorded by ALCS-integrated meters. However, current systems do not meet the required accuracy, consistency, or reliability of revenue-grade systems. Yet overall, integrated ALCS solution installations are more straightforward than revenue-grade systems paired with a basic lighting controllers. Furthermore, the tested ALCS systems offered more integrated control and data display than the selected revenue-grade systems, and were easier to integrate with BMS and higher-level controllers.