LED and PG&E
PG&E takes LED lighting to the streets
As PG&E employees walk down Beale Street in San Francisco and past PG&E’s General Office complex on a chilly winter evening, they may notice some changes in the streetlights above. Maybe the color or the shape—something just a little different from the lights on other streets. Then again, they may not notice, which is a testament to the effectiveness of the newly installed LED street lights.
The LED additions were made possible through a collaboration of PG&E and the city of San Francisco to pilot this promising new technology in San Francisco. A recently completed assessment in Oakland shows that LED street lights can reduce energy use by approximately 50 percent against traditional street lights while maintaining the high quality of light resident enjoy.
Mary Matteson-Bryan, portfolio manager in PG&E’s Customer Energy Efficiency Emerging Technologies group, is excited about the prospect of saving energy. “The outlook for LED street lighting is very promising, with our evaluations showing significant efficiency improvements in the past year. At the same time prices are falling. Now is a great time to introduce these technologies to our customers.”
LED street lighting offers advantages beyond energy and cost savings. For instance, LED street lights are predicted to last 50,000 to 80,000 hours—much longer than traditional lights—reducing maintenance costs significantly. And because LED light sources are directional in nature, street lights can be developed to help eliminate light trespass and reduce sky glow.
PG&E is also working collaboratively with groups including ENERGY STAR® and the California Lighting Technology Center at U.C. Davis to advocate for quality statewide and national standards for LED street lighting.
The LED street lights installed on Beale Street have also been outfitted with network controls that will allow remote operation from a designated central computer or a cell phone. John Sofranac, who manages street and outdoor lighting programs at PG&E, said, “This pilot program has the potential to show that customers can manage their own energy use and maintenance costs by making it easier to control the lights—remotely, by turning them on and off or even dimming them.”
LED street lights with automatic controls have the capability to provide real-time billing and faster, cost-effective maintenance through automatic alerts to field repair teams. Sofranac added, "This collaborative effort will leverage green indoor technology so that it can be utilized outdoors on these very important and valued assets."
PG&E expects to roll out this technology on a wider scale during the second quarter of 2009. The utility plans to develop LED incentives and rebates for customers who purchase and install technologies that meet qualifying standards.
Advantages of LED
- The solid package of the LED can be designed to focus its light. Incandescent and fluorescent sources often require an external reflector to collect light and direct it in a usable manner.
- When used in applications where dimming is required, LEDs do not change their color tint as the current passing through them is lowered, unlike incandescent lamps, which turn yellow.
- LEDs are ideal for use in applications that are subject to frequent on-off cycling, unlike fluorescent lamps that burn out more quickly when cycled frequently, or HID lamps that require a long time before restarting.
- LEDs can have a relatively long useful life. One report estimates 35,000 to 50,000 hours of useful life, though time to complete failure may be longer. Fluorescent tubes typically are rated at about 30,000 hours, and incandescent light bulbs at 1,000-2,000 hours.
- LEDs mostly fail by dimming over time, rather than the abrupt burn-out of incandescent bulbs.
- LEDs light up very quickly. A typical red indicator LED will achieve full brightness in microseconds; Philips Lumileds technical datasheet DS23 for the Luxeon Star states “less than 100ns.” LEDs used in communications devices can have even faster response times.