French Street Lighting System Cuts Energy Use by 35% with LONWORKS® Network
Sénart en Essonne, a fast-growing area 35 km south of Paris comprising four cities, has a street lighting network of about 3,500 streetlights. The town council wanted to reduce the area’s energy use by 35% to significantly contribute to its sustainable growth plan. The council also hoped to lower its operating budget and maintenance costs while increasing road safety.
The town council partnered with SPIE, one of France’s largest streetlight maintenance companies, to install an intelligent network based on Echelon’s LONWORKS technology and SPIE’s CityNetworks software. The system uses electronic dimmable smart ballasts to dim the lamps when appropriate, extend lamp lifetime, automatically identify lamp failures, and enable remote control in real time.
In an effort to reduce energy use in the four-city Sénart en Essonne area, the town council set an ambitious goal for its street lighting system: It aimed to save 35% on energy use each year, thereby reducing its annual carbon emissions by an average of 300 tons. The council also wanted to contain its operating budget and reduce its maintenance costs, while keeping the streets safe and easy to navigate.
To meet its goal, the council partnered with SPIE, one of the largest streetlight maintenance companies in France, with responsibility for roughly 500,000 streetlights throughout the country. SPIE worked with Echelon to propose a solution based on LONWORKS technology, an open, extensible architecture that lets control devices from multiple manufacturers interact with each other. The solution dims streetlights when there are fewer cars on the road, automatically identifies failed lamps, and enables real-time control to reduce onsite operations. It also increases light quality by using electronic dimmable ballasts that drive the lamps more efficiently and make them last longer.
Putting the Pieces Together
The streetlights are equipped with a Philips Starsense light controller that embeds an Echelon power line transceiver and drives an electronic dimmable ballast and high-pressure sodium (HPS) lamps. The Starsense controller governs the operation of the ballast and also identifies failures, triggers alarms, and takes real-time measurements of energy use, number of hours burned, voltage, current, power factor, and power usage. The streetlights are connected to Echelon SmartServer systems, which send On, Off, and Dimming commands to the controllers over the existing power line cables. The SmartServers then send this data via a GPRS network to the central CityNetworks monitoring software, which is hosted by SPIE.
The CityNetworks software gives SPIE an overall view of the streetlight system and makes it easy to manage its operation. The software automatically aggregates and records data from many SmartServers, without manual intervention. The system’s On/Off commands are based on the SmartServer’s astronomical clock, and the dimming commands follow scenarios that are easily programmed into the CityNetworks software.
Reaping the Benefits
Automatic dimming makes it possible to vary light brightness according to time of day. During rush hour, for example, the streetlights are set to an 80% brightness level, but are dimmed to 60% otherwise. In some areas, the lamps are dimmed to as low as 40% between 11 p.m. and 5 a.m., with no discernible impact on visibility. When a lamp fails, maintenance operators can be notified by an alarm on their cell phone or via e-mail. Operators can check status by accessing the CityNetworks Web portal, which is available anytime, anywhere, via a secured access network. Using the portal, operators can diagnose failures and compile lists of older lamps in the surrounding area, so multiple lamps can be replaced on a single service run. The Web Portal also lets operators control the lamps remotely, and lets them perform efficiency checks to monitor energy and CO2 savings.
Remote operation and automatic failure detection have helped SPIE reduce costs in several ways. Before the new system was installed, it could take up to 15 days to identify a lamp outage. Now, failures are identified almost instantly. And since maintenance teams no longer need to patrol for outages at night, they spend less time driving, need fewer cars, and emit less CO2. Customer service is less expensive, too, since SPIE now receives fewer calls from citizens reporting lamp outages.
“Our maintenance teams anticipate problems and diagnose them before citizens even know about them,” says Daniel Labanowski, Director of Business Development at SPIE. The system is designed for flexibility and supports hardware components from many different manufacturers. The council isn’t obligated to use a single brand of smart controllers or smart ballasts; it can choose from a number of solutions. That way, the system can continue to grow by adding the most cost-effective components.
Labanowski calls the system a model for others municipalities to follow.
“With this solution, the Sénart en Essonne area has met its goal of reducing energy costs by 35% a year,” he says. “It is a template for other cities looking for ways to support sustainable development.”
Town Council of Sénart en Essonne
Sénart en Essonne, France
• Energy use has been reduced by 35%.
• Lower operating and maintenance costs.
• Increased lighting quality and efficiency.
• The streetlight network can be leveraged as a communication network to collect data from environmental sensors and support other M2M applications.
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