With the conclusion of the Paris Climate Summit, there's even more pressure on cities to find ways to cut energy use and emissions. Mississauga, Ontario, provides an inspiring example of how cities can contribute to those efforts. It's well on track to cut one of its biggest categories of energy consumption by more than half with its decision to convert 49,000 street lights to intelligent, adaptive LEDs.
And it’s saving power well beyond the simple fact that LEDs use less energy than high-pressure sodium lights. For the first time, the city has the ability to control and adjust each light, so they’re on only when they need to shine and not blasting the streets with more light than is needed.
Dramatic cost savings achieved
As of June 2015, with more than 40,000 street lights replaced, the city saved 13.1 million kWh of energy during the previous 12 months. City officials anticipate a 55% reduction in future energy consumption, as well as 50% reduction in maintenance. At this stage of installation, Mississauga has already cut energy use by 48%.
On the maintenance side, savings reflect the longevity of LED lights, which have a life expectancy of 20 years — four times as long as traditional street lights. Energy-wise, some savings stem from the efficient LED technology, and some come from Mississauga’s adaptive lighting controls system from Elster, which is a Council Associate Partner.
The Elster Lighting Intelligence solution (or ELI) allows the city to remotely turn lights on and off, and operators can dim the lights too, which leads to additional savings. That’s because its old street lights were designed for their end-of-life strength, taking into account lamp lumen depreciation — the inevitable decrease in light output — as well as luminaire dirt depreciation, or the reduction in discernable light that occurs when lamps collect grime. This means running lights at full strength in early years results in over-lighting conditions and additional costs. In Mississauga, system operators now run the newly installed lights at 65% of their full-load value to eliminate that unnecessary and wasteful lighting.
Real savings with real consumption measurement
Once you start dimming lights, how does Enersource bill the city? In Mississauga, city lights weren’t metered. Billing was based on a calculation reflecting the light’s wattage and ballast, which is the device regulating the voltage and current that powers the lamp.
The Elster Lighting Intelligence system is able to measure voltage, current power factor and time – data points that can be used to calculate actual kilowatt hours used by the various luminaires. Because that approach wasn’t approved by Canadian regulatory bodies, Enersource questioned its accuracy.
To resolve this problem, Mississauga again reached out to Elster Solutions to install revenue-grade meters at various nodes throughout the lighting system network and gain accurate billing data off specific luminaires. The approach was designed to cover each type of luminaire used by the city. The utility uses and accepts AC data and reconciles it with the energy grade meters for billing purposes.
Not only did this technology deliver accurate billing data, it also enables the city to run lights at 65% in early years of operation.
The stand-alone ELI solution can easily extend beyond the lighting infrastructure to include additional complementary services, including 911-call location identification, evacuation route signaling, pole tilt alerts and service-door tampering alerts. Additionally, the network could accommodate other devices, such as sensors for sewer levels, air pollution and open parking spots.
Get Smart Street Lighting 101 …
Follow Mississauga’s lead. Street lights can be more than just street lights. In addition to helping you reach your energy conservation goals, they can serve as a platform for smart city services. Smart Street Lighting 101 is packed with useful information and brief case studies highlighting the benefits cities are accruing as they move to integrated street light networks that can serve as a backbone for other smart city applications and it’s free for Council members. Download your copy today.