LED streetlights making a noticable difference

Two new LED streetlights (the fourth and fifth from the left) emit a brighter and bluer light in Portobello Rd at Vauxhall as seen from the Harbour Molars in Portsmouth Dr this week. PHOTO: GREGOR RICHARDSON

Dunedin astronomer Ian Griffin chaired the council’s dark skies advisory panel when it was feared several years ago the rollout of the energy-efficient lighting could jeopardise the city’s dark night skies.

Yesterday, he said there would be an increasing number of people "surprised" by the quality of light as the installation of the newer streetlights continued and the city’s failing, up to 25-year-old high-pressure sodium lighting was replaced by "much brighter, and much bluer" modern replacements.

A few years ago, Dr Griffin, who is also the Otago Museum director, flew over the city at night and took a photograph showing the lights of Dunedin from above directed up at the sky.

He was hoping to recreate the photograph next year and "see a big change".

The "colour temperature", measured in Kelvin (K), the new lights could be in order for Dunedin to still qualify as a dark sky city was 3000K — and in some areas the council had gone further than that to protect the dark skies found above Otago Peninsula.

In some areas, the new lights would only be 2200K.

"They’ve only just started — I know 4000 sounds like a lot but there are a huge number of lights that have to be replaced in the whole city," he said.

"In defence of the DCC [the council], personally I think they’ve made a very sensible decision that kind of compromises, and gets a good result all around.

"Of course, there will be some complaints as these things need adjustments and things like that — still teething problems."

Council transport group manager Jeanine Benson said the council had received nine complaints relating to light spill since installation started in December.

In each case, lights were checked to ensure they were installed and operating correctly.

The new LEDs often ran at a higher power setting on the first night as they had not yet connected wirelessly to the central management system which controlled the lights.

Broadspectrum New Zealand had to date installed about 4000 of the 14,478 LED lights planned across the city, she said.

Seven of 19 planned base stations, which connect lights to the central management system had also been installed around the city.

Work was due to be completed in June next year.

The council and its contractors had also received positive comments about the new lights, the upgrade project, and the prompt action taken to fix faults, she said.