Attending Pittsburgh's Light Up Night celebration had me thinking about the city's lighting system and why it seems to be changing. Light Emitting Diode (LED) lighting is starting to replace traditional outdoor public street lighting. High-pressure sodium (HPS), metal halide or mercury vapor lights still comprise about two-thirds of all street lights operating in the United States. As much as 60% of the energy budget of a municipality and 40% of its energy consumption can be attributed to these incandescent lamps.
Traditional lighting tends to use more energy because they create light from heating and discharges gas in the process. Semiconductors like outdoor LED lights, on the other hand, generate light from an electric charge without the need for heat. Looking to cut waste and expense, urban planners are welcoming the use of LEDs in a variety of urban lighting situations. Street and traffic light conversion initiatives are popping up in places like Nebraska, North Carolina and Pennsylvania. Planners are also retrofitting parking garages with LED solid-state lighting (SSL). In areas without a robust electrical grid, these LED lights make use of modern solar power technology to offset the drain on a municipality's power usage and their pocketbook.
Pittsburgh is one of the cities leading the way in this LED revolution. 10% of Pittsburgh's street lights have been converted to run LEDs. An annual savings of $140,000 has been estimated by Pittsburgh's Department of Public Works, mostly from reduced maintenance expenses. Additionally, energy consumption has been halved.
Other communities have taken notice of the LED lighting in Pittsburgh and upgraded their traffic lights to LED themselves, such as the borough of Edgeworth. The borough has been able to save even more than Pittsburgh, about 60% of previous costs, based on more efficient use and reduced maintenance.
The borough next set its sights on converting the street lights to LEDs. The first hurdle faced comes in raising the higher upfront costs involved with LED bulbs—costs can range from $200 to $300, compared to $50 to $100 traditional bulbs. The city of Pittsburgh, for instance, would spend $21 million to install replacement LED bulbs but only $9 million for the metal-halide type. If the money can be raised to pay upfront costs, LEDs do tend to be advantageous in the long-term, thanks to their longer "life spans" and greater efficiency. If you are supportive of LEDs, I highly recommend a professional agency like Laface and Mcgovern Associates, Incorporated. Click for more info
A second hurdle to overcome is criticism of the bulbs' impact on the environment. Examining the entire process involved in producing LEDs, the areas of manufacturing and recycling were shown to be as bad or worse than incandescent bulbs. Risk of environmental hazards during the production phase actually rates LEDs worse than other styles of lighting. As for the recycling phase, LED circuit boards contain raw materials that make the process difficult. However, LEDs use no mercury in their constructions and fewer toxins than in metal-halide bulbs, which contain 15 milligrams of mercury on average. With all of the benefits tallied up, it is easy to see why urban planners are attracted to LED light fixtures.