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One of the 15,000 new LED and LightGrid-equipped street lamps that are being installed in San Diego.

When the City of San Diego decided to upgrade its street lighting, its main focus was on technology that performed well; but as its research progressed, the city of 1.4-million found it could install money-saving street lights that had the potential to do more than illuminate.

In January 2014, San Diego became the first U.S. city to use GE's LightGrid™ Outdoor Wireless Control System, using long-life LED (light-emitting diodes) lamps. By June, all 3,600 stylish street lights were working in San Diego's downtown. Within two years, 15,000 more will be installed throughout the city.

"The lights and adaptive controls together provide the opportunity to save so much energy," says Lorie Cosio-Azar, energy and sustainability manager for San Diego's Environmental Services Department. Cosio-Azar predicts that the city's bill for street lighting will drop by 30 per cent, about $255,000 in annual savings, realizing about a 10-year return-on-investment.

Less electricity is used due to LightGrid's wireless control system which gives usage readings for each light pole with a much higher accuracy than the typical rate of within 2 per cent. Because of this, the city will pay for the electricity it actually uses, not the higher flat-rate tariff it had been paying.

Worldwide, lighting accounts for about 20 per cent of all electricity use. For the average city, street lights − typically high-pressure sodium (HPS) lights −  account for 25 percent of a city's energy consumption, often its largest single energy expense.

How it works

On top of each LED light fixture is the LightGrid node, with a GPS chip that collects data and sends it to a wireless gateway. That gateway "speaks" with the node and transfers data about specific streetlight use and performance. The data is delivered via a cellular or Ethernet network to a server, so that usage data for every fixture can be viewed online by city staff.

A LightGrid node that collects usage data that can be viewed in real time by city staff, resulting in quicker maintenance and lower energy bills. (COURTESY GE)


Installation is easy. The one-piece node connects to the external socket of the LED light and doesn't require internal fixture changes. "The installer only has to turn it on and the light finds the network," says Rick Freeman, an electrical engineer and GE's Cleveland-based CEO, Intelligent Cities.

The lamps can be put on a dimming schedule, shedding less light in the middle of night or in low traffic areas. The ability to dim lights can result in energy savings of 40 to 75 percent, Freeman says. Alternatively, the light intensity can be quickly boosted in certain situations such as emergencies. In San Diego, for example, during special events like marathons, the street lights were turned up, Cosio-Azar says.

The broad-spectrum light from LEDs produces much better colour rendering, including in dim conditions, than HPS lights. Those not wanting bright light shining into their room at night can put in a request. "It's very customized. I've had residents call me to turn them down at night. They love it," says Cosio-Azar.

Another benefit is that maintenance workers don't have to drive around randomly looking for non-working lights. Office staff can see online which lights are not functioning and create an efficient fix-it plan. "It's an incredible maintenance tool," Cosio-Azar says. "And you know where all your light fixtures are."

And because of the lights' design, there's a drop in the amount of light that rises into the night sky, a major source of light pollution. "We've had a 90 percent reduction in uplighting," Cosio-Azar reports.

Brighter future

Freeman predicts that GE's LED lights, combined with the LightGrid software, will be in place by 2020 in many North American cities. Down the road, further capabilities, beyond saving energy and maintenance costs, will be integrated into the fixtures. Additional sensors will become available, including those able to measure factors such as particulate matter, noise, humidity and temperature. Poles could also be outfitted with components to extend wireless service.  Even downward-facing cameras can be tagged onto the poles. Data collected would address traffic, parking and environmental concerns.

"It allows for collection of real life information about things important to citizens," Freeman says. The location of light poles could become some of the most valuable real estate owned by cities, he adds.

In San Diego, Cosio-Azar says the city is ready to boost the use of LightGrid, but for now, "It feels really great to have this system. It's not just street lights. It's transforming light as we know it."


For more innovation insights, visit www.gereports.ca


This content was produced by The Globe and Mail's advertising department, in consultation with GE. The Globe's editorial department was not involved in its creation.

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