Outdoor LED lighting benefits abound
When it comes to up-to-date exterior lighting, writes ALISTAIR ROBERTSON, Australia is not that far behind the curve in terms of technologies and applications.
Civic authorities that are responsible for large-scale exterior lighting – and are willing to ‘look outside the square’ – are reaping the rewards of improved energy efficiency and reduced maintenance requirements.
Most notably, the City of Sydney has begun to seriously explore the benefit of LED (light emitting diode)-based lighting equipment for both vehicular road lighting and pedestrian areas such as walkways and cycleways. The City has been conducting a trial of LED streetlights, with one in particular from WE-EF Lighting Australia aimed at demonstrating the dimming capabilities of such a system.
While LEDs have not been installed permanently along any major roadways in Australia to date, in part because of technical, standards-related issues, the City of Sydney has pressed on and recently issued a tender that could effectively lead to the relighting of the city with LED. Up until recently, LED hasn’t been competitive in street lighting, but we’re at a point now where that situation is changing rapidly.
LEDs can now compete with the industry-standard, high-pressure sodium lamp in terms of system cost, with many other added benefits. When and how the standards catch up to reflect these benefits (which include the ability to save significant amounts of energy and maintenance costs) are yet to be determined.
HIGH QUALITY WHITE LIGHT A REALITY
The City of Sydney installation has demonstrated two levels of lighting: one that reflects its current application, being street lighting, and a second that allows for a doubling of light levels for use at special events or when an emergency occurs. Another and very important consideration is the growing preference for ‘white light’, for the lighting of both highways and city centres. This adds considerable weight to the LED argument, as high-quality white light from LEDs is now a reality.
As an example of what’s possible, between 5pm and 8pm on a weekday evening on a city street, traffic and pedestrian numbers will probably dictate the use of full power, but from 8pm until midnight, conditions may be suitable for three-quarter power. Overnight until 5am, let’s assume half power, and then a short burst of full power before daylight resumes. The weekend cycle can be completely different, if required.
POTENTIAL FOR ENORMOUS SAVINGS
It’s quite interesting that the Sydney installation actually spends most of its time operating at half power. This is obviously beneficial in terms of energy savings, but with LED there is the added benefits derived from ever-improving LED life cycles and reliability. The installation was originally intended to run for three months but could now be there for up to a year.
The ability to infinitely vary light levels is a key distinguishing factor between LED and traditional street light sources. Unlike a normal discharge lamp, an array of high-power LEDs can, with modern electronics, provide an optimised result for any given circumstance.
What’s compelling about LED in public lighting is the fact that we can today have something that has a service life of 10 to 15 years, delivering extraordinary maintenance cost savings for owners and ratepayers alike, delivering constant light output through life as well as variable dimming, and with the potential for enormous savings.
Constant light output needs explaining: until now, if the light output required for a given application was 10 lux, then the initial light level would typically be 13 to 15 lux, because the design standard is based on end-of-life performance – 15 lux means 50 percent more power consumption than is really required.
Since we installed the system for the City of Sydney, we have actually released technology that provides constant light output. In other words, this effectively means 10 lux on day one and 10 lux a decade later.
WIRELESS CONTROL AFFORDED
The City of Sydney’s tender also invited tenderers to offer a wireless control system. For almost five years WE-EF Lighting Australia has supported a system called ‘LeafNut’, which was developed by UK-based Harvard Engineering and is today the dominant player for this technology in that market. The UK is a technology leader in this field and one of the more progressive public lighting markets within the European Union (EU). The EU has an aggressive public lighting programme in place to effectively force each member state to adopt so-called BAT (best available technology), and this helps explain why this product is today very much in demand.
Could this be the catalyst for rapid change in Australia? Will government policy-makers step in and help drive market change to realise the benefits of using LEDs and electronic and dimmable control devices (ballasts) that, by 2017, will be mandatory throughout the EU? Whether progress is achieved through government directive or market-driven changes to design standards, I think it is inevitable that there will be an acceleration and therefore expansion in the volumes of LED and electronic controls being used in Australia in the coming years.
This technology is relatively expensive in terms of capital expenditure and will continue to be so, despite the inevitable benefits of commoditisation as volumes grow. The fact is that the considerable benefits are only realised when the whole-of-life cost is assessed.
Whole-of-life cost doesn’t just account for the capital expenditure or even the power consumed over a lifetime of 20 years. To gain a true and accurate assessment of the total monetary and environmental cost of a lighting system, whole-of-life costs must consider energy usage at every stage in the life cycle. We have embarked on a detailed analysis that will allow us to identify the environmental cost of making our products, operating and maintaining them through a 20-year cycle, and finally recycling them back to the next generation of products.
Australia is now committed to carbon reductions. Lighting represents almost 20 percent of power consumption, so it seems likely that LED products and smart electronics will become part and parcel of the lighting of the great outdoors.
Alistair Robertson is managing director of WE-EF Australia.