Approximately 53,500 street lights under city management will be converted to energy efficient LED units between March 2018 and December 2019 under a project announced by Mayor Kirk Caldwell Thursday.

The project will cost about $46.6 million, about $10 million of that in interest and other financing costs, the city said. But the city will not need to front any money to contractor Johnson Controls under the terms of the contract. Financing is provided by First Hawaiian Bank.

The project will pay for itself within 10 years, after which the city will save about $5 million annually, Caldwell said. That will cut the city’s energy costs by about 60 percent, he said.

LED stands for light- emitting diode.

Conversion work will begin in more rural areas first and much of the installation will be done during nights and weekends to minimize traffic impacts, Caldwell said.

Besides being brighter and more energy efficient, the LEDs will use a control system that will allow city officials to manage remotely the street lights on an individual basis. The control system also will allow the city to measure the energy consumption of each light.

About 90 percent of the new LED fixtures will be of the 3000K correlated temperature (CCT) type and will be used in residential areas. The remaining 10 percent or so will be 4000K CCT lights and will be used in key arterial streets such as King Street. Thoroughfares in the Waikiki Special District will use 3000K lights.