Acuity Brands Lighting
Since adopting a greenhouse gas emission reduction policy in 201…
Converting energy savings to cost savings
To fully realize savings, the city also invested in Acuity’s ROAM wireless network to control and monitor the lights. Nodes, or sensors, on each LED light communicate with each other in a wireless mesh network, meaning multiple sensors transmit data so a failure of one link won’t compromise the entire system. The built-in redundancy improves reliability, especially in harsh weather.
Information about each streetlight, including energy consumption, is sent via Ethernet or cellular connection to a network operations center, which stores and manages data from the entire system. For West Richland, it was cheaper and more secure to use Acuity’s server than to install one in-house.
In addition to a one-time setup fee for providing and hosting the data server, the city has an ongoing service contract with Acuity for server maintenance and support. The vendor also trains public works and Benton REA staff who will use a web-based portal to access the ROAM Concierge software suite.
Woodruff can now check the status of streetlights without waiting for residents to report outages, generate work orders, set on/off and dimming schedules, and monitor energy use down to the individual fixture.
Spending to save (energy)
Although replacing all of West Richland’s 1,097 streetlight fixtures with LEDs made long-term financial sense, the project came with a hefty pricetag. However, the energy-saving measure was eligible for a series of grants and incentives. Read More
“Adding ROAM controls essentially creates one giant meter,” says Feiten. “But no matter how much energy the city saved, it will not have resulted in any cost savings without Benton REA agreeing to use the system’s metering capability.” Convincing the utility to switch from an unmetered flat rate tariff to usage-based billing was key.
Acuity Brands’ technical staff walked through the ROAM system with Benton REA representatives, emphasizing its +/- 0.5% metering accuracy and safeguards to prevent data loss in a power outage. Although the utility had never used streetlight data for metering or billing, it embraced the plan to save energy and improve safety for its member-owners: the citizens of West Richland.
“Giving Benton REA access to the ROAM data for metering and billing means we pay for the energy we use, not an estimated amount,” says Woodruff. The city is moving to a consumption-based tariff at $0.072 kilowatt hours, reducing the average cost per kilowatt hour by more than 26%.
Woodruff also expects to save money on maintenance. Although the city is now responsible for maintaining the lights, previously maintained by Benton REA, the luminaires are warranted for 10 years with a useful life of 100,000 hours, or more than 20 years of dusk to dawn operation. This can be extended even further with dimming strategies.
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