Tauranga City Council is spending an extra $5.5 million on street lighting to take advantage of a once-only subsidy offer.

The New Zealand Transport Agency has announced an 85 per cent subsidy for local authorities that convert street lamps from sodium or mercury vapour to light emitting diode (LED) lighting.

The subsidy is only available for 2017/18, so we are grabbing the opportunity to begin a three year project to replace our 12,000 residential street lights, says councillor Leanne Brown.

Of the $5.5m the council will get back 85 per cent from NZTA, says Leanne.

'I think we have 1000 as part of a trial now,” she says. 'I don't know whether they are commercial or residential.”

While $5.5 million seems a lot, there will be energy efficiencies, such as a central monitoring system where the council staff can monitor turning lights on and off and know when lights are not working.

Converting to LED lighting has the potential to save up to 60 per cent of the electricity consumed by conventional high pressure sodium lights. When these lighting assets are adaptively controlled through a centralised management system, for example through dimming, total energy savings can be up to 70 per cent.

LED lights are also much cheaper to run, require less maintenance and have a much longer life time, 20 years compared to four years for HPS lights. International studies have found that LED lights help reduce urban road accident rates due to increased luminescence and white lights, compared to the yellow light from HPS lights.

A present value calculation for the Tauranga Eastern Link estimates a payback period for LED lights of approximately 11 years, depending on supply and installation costs, line charges and LED failure rates. As a result, LED lights are the preferred technology for new installations on Transport Agency state highway projects.