HONOLULU (HawaiiNewsNow) - By: Jim Mendoza
This fall, the city will begin replacing Oahu's 51,700 streetlights with LED lamps.The city says the new lights will improve road safety and save on energy costs. Shields will keep light from shooting upwards or sideways.
"One of the beauties of the LED is that it's a directional light, so it will be faced directed straight down to the street," city Design and Construction director Robert Kroning said.
But University of Hawaii astronomers argue the city's LEDs will generate a high amount of blue light and hinder telescopes on Haleakala from spotting asteroids.
"Every ten percent brighter that the sky gets from Honolulu lights basically makes our telescopes ten percent smaller. And as it gets really bright down near the horizon we're basically blind," said Richard Wainscoat of the Institute for Astronomy.
Kroning insists the LEDs the city picked will reduce sky glow. He cites Los Angeles as an example. The city changed 140,000 street lights to LED.
"This is what it looked like beforehand," he said, pointing to before and after pictures. "You can clearly the glow in the sky compared to what it looks like today -- the reduction in the sky glow."
But the Sierra Club believes the stronger blue hue will confuse animals into thinking its daylight rather than night.
"That blue bump in the spectrum is a significant effect," Kevin Jim said. "It also mimics to some degree moonlight which some species use to navigate."
Wainscoat recommends an LED he said generates half the blue light as the ones the city will install.
Kroning said the city could use that lamp but it would be at the cost of some of the energy savings.
"And possibly some of the safety that goes along with that," he said.
The city installed 400 of the new LED lights in four neighborhoods as a demonstration project. The islandwide installation will cost about $60 million. The contractor will be paid with money the city saves on energy costs.