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LED traffic signals
LED traffic signals such as this
one near the Capitol, save energy and money without sacrificing safety. (Photo by Morgan Ong)
The decade-long conversion of Sacramento-area traffic signals from incandescent lamps to light emitting diodes (LEDs) is saving SMUD 1.4 megawatts and should climb to 2 megawatts when all intersections have been converted.
Since the city of Sacramento converted its first two intersections to LEDs in 1994, more than 1,000 of the 1,300 intersections in Sacramento County have made the switch.
According to manufacturers, LED traffic lights last as long as 100,000 hours. In addition to longevity, a single LED traffic light uses just 12 watts to operate, compared to the 150 watts used by an incandescent bulb, which has a lifespan of 8,000 hours.
The savings in energy and maintenance costs are obvious. But that wasn't the case in 1993, when SMUD Commercial
Services asked one of its energy specialists, Stephen Stinson, to explore the new application.
"In the early '90s, a lot of jurisdictions were wary of the technology," Stinson said. "Would the LEDs be bright enough? At the time, a 12-inch LED bulb cost $350. Who could afford it?"
Stinson experienced a similar skepticism, but he began a dialogue with the traffic divisions of both the city and county. The turning point came in April 1995, when the city of Sacramento converted its first large intersection -- Pocket and Greenhaven roads -- to LEDs. The city's 30-day electric bill for that intersection dropped from $148 to $21.40.
The savings is much greater today -- $557,000 annually across the county.
Additional motivation came from financial incentives. The District offers local jurisdictions -- the city and county of Sacramento, the cities of Citrus Heights, Folsom and Elk Grove -- rebates of about $225 for each on-peak kilowatt that they reduce.
"The District created an environment that allowed us to do this," Stinson said. "The incentives were obviously important, but the education we provided and the information we shared pertaining to this technology was significant."
Most of the converted lights are red, for two reasons: Red LEDs are cheaper than green and amber LEDs, and traffic lights are red 60 percent of the time.