Silver Spring Networks (SSNI) has been saying for some time that its smart meter networks can be used to link all kinds of “smart city” devices, including streetlights. On Thursday, it announced its first project on that front -- a 75,000-streetlight deployment with long-time customer Florida Power & Light that connects to, and enhances, the network it’s already deployed for FPL’s 4.5 million smart meters.
The deployment in the Miami-Dade County region isn’t the first smart streetlight project for Silver Spring -- the Redwood City, Calif.-based company is networking about 20,000 streetlights in Copenhagen, and is doing a pilot project in Paris. Nor is it the first such project of its kind in North America -- grid networking vendors including Echelon, Sensus and others have been deploying digital sensor and control networks for years now.
But it is the single largest public lighting network to be deployed in North America, and notably, the first to ride on the same network used for smart metering, according to Sterling Hughes, Silver Spring’s senior director of advanced technology.
That means that each networked light will serve a dual purpose for the utility, he said -- first, to remotely control lighting, detect outages and diagnose what parts are needed to replace them, and second, to extend and strengthen the wireless mesh network they connect to.
“To them, a street light is just another sensor on the network,” he said. FPL manages about 500,000 streetlights across its service territory, and they run on the same grid infrastructure that powers homes and businesses, making them useful sources of data pertaining to outages and restorations.
Beyond that, “the lighting serves as a perfect canopy to strengthen the network,” he said. That’s an important consideration for a mesh-based wireless topology, in which each node in the system serves as a link to every other node as they move data from endpoints to the collectors that connect to utility control centers. FPL has been using its Silver Spring network to connect distribution automation systems, detect outages and analyze data streams for grid health insight, and is looking at specific network improvements to come as part of its addition of 75,000 street light nodes, Hughes said.
Putting together a network node that can figure out what's wrong with an HID lighting ballast system at the same time it helps grid operators triangulate faulty transformers isn't a simple task. "You’d be amazed how much engineering and sensoring goes into lights," he said. Silver Spring is leaning on the help of a number of smart lighting technology providers it has partnered with over the past year or so to do this kind of work. It's also tapping the capabilities of its SilverLink Sensor Network, which allows its networking nodes to be programmed as "virtual sensors" to parse and prioritize certain data for different operations, he said.
This combination of lighting maintenance and operational improvements and smart grid network enhancements put FPL’s new project in a different category than most of the other smart streetlight projects we’ve seen deployed to date. One key difference is that FPL’s project doesn’t include changing over streetlights to LEDs, Hughes said.
Almost every “smart” streetlight project to date has been driven by the business case of LED replacement, which pays off in lower energy consumption, longer lifespan and reduced maintenance costs. Having digitally controllable LEDs in place has, in turn, justified the expense of wirelessly connecting them, as has been the case in Silver Spring’s projects in Copenhagen and Paris.
“LEDs definitely provide a kicker on the business case,” Hughes said, while networking non-LED streetlights hasn’t penciled out on its own in most cases. But with Silver Spring’s smart meter network in place, “adding one more application onto that network doesn’t add a ton of costs” for FPL.
Hughes estimated that Silver Spring’s U.S. utility customers collectively own, manage or operate about 6 million streetlights, in conjunction with city and county governments. Now we’ll see if any of them see the same value in leaping from smart meters to streetlights.