The ugly, inefficient mercury vapor, metal halide, and sodium lights that have cast a jaundiced glare into the night sky over many cities are slowly but surely being replaced with LED-based or solid state lighting luminaries. These lights are not only easier on the eye, but save money. Boston believes that their SSL street lights will save the city $1.1 million dollars a year, cut down on millions of kilowatt hours of power consumption and about 5,000 of tons of greenhouse gases.
Another SSL project in Weston, Florida looks to save about $160,000 in that city’s annual energy bill, and is being partially funded by the Department of Energy through an Energy Efficiency and Conservation Block Grant. The lights are not only money and energy saving, but as they give off a soft, clean, white light that cuts down on glare, they’re good to look at as well. They also eliminate shadows between the light poles and so increase visibility. LEDs are also being set up in the area around Bath and Bristol England, especially in their traffic circles, which the Brits call “roundabouts.” These lights can also be dimmed during reduced traffic hours late at night.
Another LED project is underway in Edmonton, in Alberta, Canada, which will cut their greenhouse gas emissions by about 239 tons, and save each neighborhood $4,300 a year in the long run.
Besides saving energy and money, the best things about the LED or SSL lights is they don’t cast that glare up into the sky and add to light pollution or what some call “light trespass.” It may even be possible to finally see the stars and planets from neighborhoods who use these lights.
These new lights are more expensive than the old ones, but they last three to four times longer. They have lifespans of up to 18 years.