LIGHTING ECONOMIST
How green are your LEDs?

Dave Tilley asks whether the desperate quest for energy eficiency – and the enthusiastic adoption of LEDs – has blinded businesses to the true meaning of sustainability

Is it time to take stock? Should the lighting industry take a step back and take a more detailed look at the lighting phenomenon from the electronics industry that is the light emitting diode?

If a fluorescent lamp fails, it can be replaced little disruption


LEDs have all the key elements of a ‘sustainable’ lighting product. Low energy consumption relative to light output and long life when compared with traditional light sources. Sure, there’s a price to pay for these attributes, but the sustainability argument looks to be won.

Prerequisites for performance

Before we compare two installations – one fluorescent and one LED – it is worth noting why LEDs are such expensive lighting products. There are a couple of prerequisites to ensure good light quality and ef cient performance from an LED.

● The quality of the chip and the lens system must be high
● The junction temperature must be managed, usually with a built-in heatsink
● The electronics must be independently tested

The above elements define the quality and performance of an LED.

On the other hand, with a fluorescent luminaire there are also a number of fundamental elements that ensure quality and performance.

● Lamp – branded, with published operating criteria
● Control gear
● Reflector – light output ratio must be at least 70

When comparing LED and fluorescent light sources, operating life is a key consideration. The longevity of a fluorescent source can be expressed in terms of ‘average rated life’ with known service parameters, but the lives of LED sources are far more difficult to pin down, despite LM70 and LM80 tests.

Consider sustainability

So let us review two installations – one LED and one fluorescent – with sustainability in mind.

In simple terms the fluorescent installation is governed by lamp life. If a lamp fails, it can be replaced without any signi cant disruption to the installation. Not only that, the failed lamp can be recycled through a registered scheme and the sustainability cycle has been completed.

Even if the control gear fails it can be replaced as part of a maintenance regime and the redundant control gear recycled through a registered scheme. If an LED downlight fails, however, the picture is a little different.

The LED downlight will have to be removed from the ceiling and replaced with another downlight.

This process is more disruptive and expensive than simply replacing a fluorescent lamp. It may even involve the purchase of a new LED before any warranty process can be enacted.

Disposal of the LED

As well as the replacement cost there is the little matter of the new LED downlight – probably more than 10 times the price of a fluorescent lamp – and the disposal of the failed LED. The disposal will have to be far more sophisticated than traditional methods to ensure the sustainability cycle is closed.

The key question is: ‘Are there systems to recycle failed LEDs that are genuinely sustainable?’ And how will this affect the carbon footprint of the LED product? Perhaps a more important question is:

‘Have any of the LED manufacturers calculated the carbon impact of these new lamps and luminaires and the recycling processes?’

LED has been promoted as the technology for use at high level, because of the life and operational durability claims that have been made for them. I am not suggesting that LED is not viable for this or indeed any other efficient projects.

The cost of over-promotion

But perhaps a word of caution before – as with many previous lighting innovations – the lighting industry over-promotes LED technology as something it is not, then pays the price.

I can already hear those LED manufacturers that are making interchangeable LED modules arguing that interchangeability is the answer. Well, that argument may have some substance, but if the electronics fail the LED module will not operate.

There are of course other LED configurations – remote drivers and LED lamps, for example.

Ironically, the LED retrofit lamp, not popular with some purists, is probably the most successful in terms of sustainability because it can be easily replaced and causes no more disruption than a traditional light source.

However, even the LED retrofit lamp market has an Achilles heel. As LED technology continues to evolve at a spectacular rate, redundant stock builds up.

A 3W GU10 has been superseded by a 4W then a 6W and so on. The major manufacturers can write down the redundant stock, but is this really a picture of sustainability?

THE LIGHTING ECONOMIST’S VERDICT

Where does this leave us?

First of all it is worth making it clear that the UK has a number of good recycling schemes – Recolight and Lumicom, for lamps and luminaires. I am sure the recycling of LEDs is high on their agenda.

The previous article considered the failure rate of LED lamps and luminaires. As part of understanding and accepting the finite lives of the new light source, the industry has to consider the recycling and sustainability implications. The message to end users must be one of measured caution.

Claiming that a product has a life of 40,000 hours or more with no mention of failure can only result in client disappointment. And when one does fail, there is no support mechanism.

You can contact Dave Tilley at dtilley@nrgstar.com

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