A long-discussed project to convert all of the city’s roughly 53,500 streetlights to light-emitting diode (LED) fixtures will get underway Monday in the North Shore, Leeward and Windward parts of the island, city officials announced Friday.

The total cost of the two-year project is $46.6 million, which includes construction, financing and the warranty and network services over a 10-year period. Contractor Johnson Controls is being paid $36.7 million for the construction portion of the work.

City officials say the new lights will use about 60 percent less energy, saving about $5 million annually in electricity costs. At that rate the project should pay for itself within a decade, they said.

While using more energy-efficient lights, the project has drawn complaints from groups concerned about how the brighter LED bulbs might affect human health and safety, seabirds and light “pollution” in the night sky. The Sierra Club’s Oahu chapter and local scientists have argued the LEDs being installed by the city are “bluer” and have a more harmful impact than more technologically advanced versions now on the market.

Sierra Club officials told the Honolulu Star-Advertiser in December they had been urging the Caldwell administration to use 2700 kelvin LEDs instead of the 4000 K and 3000 K bulbs being used in the conversion. (Kelvin is the term used to express “color temperature”; the higher the kelvin, the “cooler” or more bluish-white the light.)

“The blue light component of the city’s chosen lights has been scientifically proven to decrease night vision, make it more difficult for people to sleep and hurt their health, severely and adversely affect night-flying seabirds, and greatly increase the sky brightness to the detriment of astronomy on Hawaii island and sky gazers on Oahu,” the organization said.

“Despite this, the city is planning to proceed with a solution that is likely to lead to public outcry and further taxpayer expenditure to correct the mistake they are about to make.”

The city, in its news release Friday, said new LED bulbs with a color temperature of 4000 K will be used on only about 10 percent of streetlights, including along busier arterial streets such as King Street. The other 90 percent of new installations, including those in residential areas and all of Waikiki, will have 3000 K LEDs that emit a “warmer” glow and are recommended by the American Medical Association, according to the project website.

What’s more, “the LED street lights in the residential areas will have a flat glass (lens) that will eliminate uplight and will have an internal reflector system to focus the light on the roadway” and not onto private property, the website said. “This will also greatly reduce the impact to migratory seabirds.”

The construction work could have some impact on traffic, but city officials said they are working to deal with that. Most of the work will take place from 8:30 a.m. to 3:30 p.m. weekdays. However, the city might do some work in heavily congested streets at night and on weekends to minimize traffic impacts, officials said.

Work on the project will begin on the North Shore and Leeward and Windward areas, and then in Central Oahu, Pearl City and downtown Honolulu.

Tim Sakahara, a spokesman for the state Department of Transportation, said Johnson Controls is under contract with the state to convert 20,000 highway and tunnel light fixtures, as well as 5,200 interior and parking light fixtures, in a move that will cut the state’s electricity bill for street lighting by an estimated 43.4 percent.

City officials said the state’s LEDs have a color temperature of 4000 K.

As for the city project, the new fixtures will be controlled by a wireless network that allows city traffic managers to manage them individually or as a part of a group.

For project updates and more information, including an installation schedule by ZIP code, go to the project’s website at myoahu­streetlight.com.

Caldwell first mentioned his desire to switch to LEDs soon after he became mayor in 2013.

“Transforming Oahu’s communities to become more sustainable, resilient and environmentally friendly is going to take a multifaceted approach, and replacing all of our street lights to energy-saving LEDs is a big step forward in this process,” he said in a statement Friday.