Smart Lighting Summit: LED lighting the way for Adelaide’s streets

Donna Kelly

Conference: The City of Adelaide has taken part in a global trial of LED outdoor lighting organised by The Climate Group.

City of Adelaide senior engineer Belinda Hill told this week’s Australian Smart Lighting Summit 2013 that she had pushed for the longest trial among the cities chosen to take part,  including London, New York, Toronto, Sydney, Hong Kong, Kolkata, Thane (a suburb of Mumbai) and Quezon City in the Philippines.

Ms Hill, who is lighting and underground asset manager at the City, said she was in charge of $62 million dollars’ worth of assets.

“[And] that does worry me sometimes because decisions can be made throughout life of the asset and they can be based on a political decision, a financial decision or a non-technical decision,” she said.

“It is a big weight on my shoulders that we do the right thing because it is going to be something that will cost the council and the ratepayers.”

Ms Hill said the council, in 2009, had created a “Go Green with Energy” project with the aim of replacing existing street lights, some which were quite old, with energy efficient lights.

But with LED quite new technology and without being able to “guarantee something new won’t break”, Ms Hill jumped at the chance to take part in the Climate Group’s worldwide study.

The first trial, which went from November 2009 to June 2012, with Ms Hill pushing for an extra six months, took place in the Adelaide Park Lands.

A quite secluded pathway, already lit by metal halide luminaires and away from street lighting, was chosen for the trial with half of the existing lights replaced by LED.

The council went for a RUUD Spider with 60 LED, 74 watts and, initially, 6000 kelvin.

This was later dropped to 4000 kelvin as the preferred option with Ms Hill telling the summit audience that McDonald’s restaurants chose 6000 kelvin because it was not a pleasant light and encouraged people to leave the restaurants rather than linger.

She said the LightSavers global LED trials saw lighting managers, including herself, from nine of the cities independently testing the performance of more than 500 luminaires representing 27 different commercially available LED products, using the same measurement protocol.

Key findings included:

• LEDs achieved the expected 50 to 70 per cent energy savings and reached up to 80 per cent savings when coupled with smart controls
• Even with these energy savings, the vast majority of tested products exceeded local lighting standards
• Many commercial LED products tested show behaviour indicative of lifespans of 50,000 hours, though the results from the trials should not be used for predictive purposes
• LED products generally show very little change in colour
• The “catastrophic” failure rate of LED products over 6000 hours is around one per cent, compared with, for example, up to 10 per cent for metal halide fixtures over a similar time period
• In cities where surveys were conducted, the public prefers LED illumination, with about 90 per cent of survey respondents supporting a full rollout of LEDs across city street lights.

A summary of results for Adelaide, recently published in The Climate Groups’s Adelaide LED Trial – Final Report found:

• Illuminance: The LED luminaire provided illuminance four times greater than the illuminance produced by the metal halide luminaire. At the beginning of the trial, the City opted for a higher illumination LED product in order to improve public safety in the park at night
• Correlated color temperature: There was a minor shift in CCT of the LED product over the initial 15 months of the trial, less than five per cent. For the LED luminaire, this amounted to less than three per cent on an annualised basis.
• Energy: Despite its much greater brightness, the LED luminaire reduced electricity use compared with the baseline metal halide luminaire by approximately 18 per cent.
• Luminaire target area system effectiveness: The LED luminaire was significantly more effective at directing light to the surface of the pedestrian path. Indeed, the LED luminaire used five times less energy to deliver a unit of average illuminance to the surface, compared with the metal halide luminaire.
• Lumen maintenance: For the purpose of this trial and study, we assumed a lifetime of 50,000 hours for the LED product tested. Thus, lumen depreciation exceeding 2.8 per cent on an annualised basis, net of luminaire dirt depreciation, would be less desirable than a value in the range of 2.8 per cent or less. The lumen output of the LED luminaire declined by five per cent on an annualised basis over 19 months, after an initial burn in period of 1000 hours.

In conclusion, the LED luminaires provided five times more illumination of Park 2’s pedestrian pathway while still reducing electricity consumption by approximately 18 per cent.

Meanwhile, colour temperature shift of the LED luminaires was less than three per cent.

The LED luminaire’s lumen depreciation on an annualised basis was five per cent, taking into account dirt depreciation. Lumen depreciation in the range of 2.8 per cent or less would have been desirable, performance indicative of a product lifetime of 50,000 hours defined by a decline in lumen output of 70 per cent.

Ms Hill told the summit the City of Adelaide had now installed 1476 LED street lights.

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