Monday, March 3, 2014

LED Street Lighting in Portland

The Portland Bureau of Transportation owns approximately 55,000 streetlights to brighten our roads and walkways. Streetlights make traveling safer by illuminating the road ahead of a traveler and highlighting hazards and curves. Pedestrians and bicyclists are safer when streets are well-lit and crime is reduced. 

Cities across the United States are modernizing their streetlights to save energy and maintenance costs without sacrificing safety by converting their streetlights to LED lights. Portland wants to do the same. In fact, the city just converted the “lollipop” streetlights in the South Auditorium district to LEDs with federal stimulus. 

The majority of our streetlights are called “cobrahead” lights and use high-pressure sodium (HPS) bulbs. These lights get the job done, but are costly to maintain because bulbs needs replacing every five years. LED streetlights are estimated to be replaced every 20 years. These HPS bulbs use more electricity than LEDs, which is costly and has environmental consequences because of how the electricity is produced. LED streetlights use approximately 50 percent less energy than our current lights. This will reduce our streetlight costs by approximately $2,000,000 per year because we’re using 18 million fewer kilowatt hours of power. Consultants working on behalf of the Bureau anticipate the change of our cobrahead lights to LED technology will keep up to 10,500 tons of greenhouse gases out of the atmosphere.

The upfront costs to change out Portland’s streetlights will be a major expense, but result in a net savings of money for Portlanders in the end due to lower electricity and maintenance costs. To pay the upfront costs, PBOT has gotten approval from City Council to issue General Obligation bonds for replacing approximately 44,000 of the cobra head street lights. 

A typical LED streetlight pays for itself in six to eight years by reducing the power bill. Instead of replacing all of Portland’s lights this year, the city is going to get the most our of its current lights by letting them operate for a few years before replacing them. Since the high-pressure sodium lights have a five-year lifespan, we expect full replacement to take less than five years. 

Evaluation of conversion the more expensive ornamental street lights will be completed in the coming months. A plan will be developed to replace these lights in a financially practical approach.