LEDs set to improve sustainability of Australia's street lighting

Street lighting is claimed to be the single largest source of greenhouse gas emissions from local government, and the annual energy cost of public lighting in Australia exceeds $125 million (and more than $250m including maintenance). In this article, Bryan Douglas, CEO, Lighting Council Australia, explains the compelling case for converting street and other public lighting to LED technology and the reasons why municipal authorities need to exercise caution.

According to a report prepared for the Commonwealth Government in 2011, there are approximately 2.28 million street lighting lamps in service in Australia, with around 33% on main roads and 67% on local roads.

Because of their longevity, controllability and above all efficiency, LEDs are now an attractive substitute for conventional mercury vapour, high-pressure sodium, metal halide and linear and compact fluorescent technologies used in minor roads and other public spaces. A further major environmental advantage is that LEDs do not contain the toxic substance mercury.

These cost and environmental factors make an increasingly compelling case for the conversion of street and other public lighting to LED technology. However, while there is now suitable LED product on the market for streets and other public places, municipal authorities need to exercise caution when investing in the technology.

LED street lighting comes of age

Case study 1: City of Sydney

The City of Sydney is in the process of replacing 6500 conventional lights with LEDs in central Sydney, Glebe, Darlinghurst, Zetland, Pyrmont, Kings Cross, Newtown and Redfern. More than 2600 street and park lights have already been installed.

The City announced in August 2013 that it had saved almost $300,000 and reduced energy use by more than 25% since March 2012. Public lighting accounts for one-third of the City’s annual electricity bill and a large part of its greenhouse gas emissions.

Importantly, more than 90% of people surveyed by the City said they found the new lights appealing and three-quarters said the LEDs’ white light (cool colour temperature) improved visibility.

The NSW Government is following the City’s lead by encouraging 41 councils across Sydney, the Central Coast and the Hunter regions to work with Ausgrid to implement similar LED lighting projects.

Case study 2: City of Los Angeles

In one of the largest solid-state lighting retrofit installations in the world to date, the Los Angeles LED Conversion Program replaced over 141,000 streetlight fixtures with LED units over a four-year period. The expected savings of the new lights has exceeded the initial program goals. Energy use has been reduced by 63% and carbon emissions by 47,583 metric tonnes a year. This proposal has generated savings in energy and maintenance costs that will pay for the estimated loan amount in seven years.

Ed Ebrahimian, Director of the Bureau of Street Lighting at the City of Los Angeles, recently commented: “The importance of the LED Conversion Program cannot be overstated. It is a shining example of how green technology can be both environmentally responsible and cost effective. With the LED program, we have transformed the night landscape of the City of Los Angeles, made our city safer and pedestrian friendly at night, and have exceeded our initial program goals on both energy efficiency and CO₂ reductions.”

Case study 3: Seattle

Seattle’s publicly owned utility Seattle City Light is converting its residential streetlights from high-pressure sodium lights to LEDs. The decision was made after thorough evaluation and positive results from pilot projects. Seattle City Light has characterised the benefits of LED conversion as:

• approximately 48 to 62% lower energy consumption;
• high-pressure sodium luminaires, most installed in the mid-1980s, are at the end of their useful lives and failing. LEDs will provide better service reliability and lower maintenance costs;
• reduction in greenhouse gas emissions: in manufacturing, when LEDs are in use, and fewer service vehicle trips for repairs will mean a reduction of about 20,000 tonnes of carbon each year;
• replacement of luminaires with LED fixtures will provide three to four times longer field life than high-pressure sodium;
• LEDs are not affected by truck and roadway structure vibration;
• better light quality (whiter/cooler colour rendering);
• light quality improves safety because of depth of field and peripheral vision enhancements without distorting colour.

The utility has estimated the simple payback for LED conversion of residential lights at 7.7 years. Once all residential fixtures have been replaced, they will save the City an estimated $2.4 million in annual energy and maintenance costs.

Case study 4: New York City

New York City has embarked on an LED conversion project which when completed will be even larger than that of Los Angeles. The project began along highways in 2011 and by 2017 240,000 lights will have been replaced across all five boroughs.

Australian road lighting standard

It may come as a surprise that the current Australian standard for road lighting excludes LEDs.

The Australian standard AS 3771 - ‘Road lighting luminaires with integral control gear’ was published in 1990 as a consequence of a multitude of contracts and specifications issued by the former electricity supply authorities. In 2004 this was superseded by AS/NZS 1158.6 ‘Lighting for roads and public spaces Part 6: Luminaires’, which adopted some of the principles within the international road lighting standard. However it was - and remains - highly prescriptive, so much so that it effectively rules out the use of LEDs.

In an attempt to redress the prescriptive nature of AS/NZS 1158.6, Standards Australia committee LG-002 is now updating the standard. The first stage will see some reduction in the prescriptive elements and, importantly, the admission of LEDs. The second stage of the reform process will take longer and is expected to result in a standard that more closely reflects the international standard IEC 60598-2-3 ‘Luminaires for road and street lighting’.

International Energy Agency’s 4E SSL Annex

The Solid State Lighting Annex was established in 2009 under the framework of the International Energy Agency’s Efficient Electrical End-Use Equipment (4E) Implementing Agreement to provide advice to its 10 member countries - one of which is Australia - seeking to implement quality assurance programs for SSL lighting. The goal of this work is to reduce the risk in using SSL products and to provide governments and consumers with recommendations they can trust when investing in SSL products. The performance tiers identify a suite of metrics and values related to minimum performance values of SSL for energy efficiency, lighting quality and safety.

In October 2013, the IEA published ‘Outdoor Lighting (Street Lighting)’ as part of the 4E SSL Annex. The performance criteria for this category of lighting include:

• minimum downward luminaire efficacy (lm/W);
• lumen maintenance;
• minimum rated luminaire lifetime (F50);
• colour rendering index (CRI);
• colour maintenance (Δ u',v' at 6000 h);
• operating temperature (range °C);
• ingress protection (IP), impact protection (IK);
• correlated colour temperature (K) and tolerance <6500 K;
• chromaticity tolerance (Du’v’);
• flicker (flicker index).

Further information may be found at http://ssl.iea-4e.org/.

Mercury issues

Mentioned earlier, the significant environmental attribute of LEDs is that they do not contain mercury. Mercury vapour, high-pressure sodium, metal halide and linear and compact fluorescent lamps constitute the vast majority of current street and public lighting - and all contain mercury.

Currently, 90-95% of mercury-containing lamps end up in landfill. Given their numbers and the relatively high proportion of mercury in the higher wattage lamps, the amount of mercury going to landfill from road and street lighting is significant. Mercury in landfill converts to the toxic methyl mercury and spreads through the wider environment through air, water and soil.

Hence, conversion to LED street and public lighting can have a major beneficial effect on the environment. But what to do with all those mercury-containing lamps currently in the system when they are replaced with LEDs or when they otherwise reach end-of-life?

FluoroCycle is a voluntary program that diverts mercury-containing lamps from landfill. Local government, public utilities and others responsible for disposal of roadway, street and other public lighting are encouraged to join the program. For more information, visit www.fluorocycle.org.au.

Careful consideration required when investing in LEDs

Earlier this year, Lighting Council Australia invited Professor Georges Zissis, head of the Light and Matter Research Group at LaPlaCE (Laboratoire Plasma et Conversion d’Énergie) at the University of Toulouse and a world-renowned expert in lighting systems research and design - and in particular its application for street lighting - to deliver seminars in Australia. In addition to his role at LaPlaCe, Professor Zissis is Task 1 Leader of the IEA’s 4E SSL Annex referred to above.

Professor Zissis characterised the advantages of LEDs as high luminance, excellent colour saturation, high luminous efficacy, high energy conversion efficacy, small dimensions and lightweight, robustness, long life span, low-voltage power supply and ease of dimming. However, he went on to document some of the issues and problems with the technology. These included:

• eventual limits to efficacy of around 250 lumens per watt estimated to be reached in 2025;
• a marked difference between LED efficacy and system efficacy arising from thermal management losses, optical losses, ballast losses and photometry losses;
• marked variations between claimed and tested performance;
• falsification by some vendors of test certificates;
• a multiplicity of conflicting standards;
• issues with power supplies which include poor manual soldering, unreliable wiring, low-quality components, low-quality chemical capacitors, hot points and low mechanical quality;
• power factor and cosφ issues;
• flicker;
• blue light hazard;
• environmental impact.

Municipal authorities and others contemplating a switch to LEDs are well advised to do their homework. Speak to electricity utilities and others who have conducted LED trials. Above all, deal only with reputable suppliers.