Time for the LED industry to come clean

COMMENTARY from the September/October issue of LEDs Magazine.

Compared with CFLs, replacement LED lamps have a number of advantages and drawbacks. While CFLs have for some years been marketed as energy-efficient light sources, LED lamps are only barely starting to become a viable alternative, reflecting the current performance and cost of LED products.

However, one factor may lead to the downfall of CFLs, to the ultimate benefit of LEDs. In a word: mercury. CFLs don’t contain much, but it’s there. Attitudes vary as to the dangers posed. There was the story of a broken CFL in a US home that resulted in a clean-up operation costing thousands of dollars. In contrast, I was recently sent four free CFLs by my UK electricity supplier. In a Q&A, the question “Should I be worried about mercury content” was answered with “No. The material involved doesn’t pose a significant health problem. If a bulb breaks ventilate the room for a few minutes.”

The truth is somewhere between these extremes, but there’s no doubt that the words “contains mercury” are not generally positive for any product. Consumer perception or legislation may eventually dictate that only zero mercury content is acceptable.

So what about LEDs? Well, there’s no mercury, so that’s a good start. Ideally, we would be able to say that LEDs contain no toxic materials at all and are fully recyclable, but it’s not clear this is the case. In fact, there are numerous types of LED containing many different materials, albeit in small quantities. Whether or not a single LED might cause a problem is a different issue from whether a large pile of LEDs in a landfill might result in contamination of groundwater.

California recently listed gallium arsenide (GaAs), a semiconductor material, as a carcinogen (see article). GaAs is used in some types of LED, primarily red, orange, amber and infrared devices, but it is not found at all in gallium nitride (GaN) LED chips that emit in the green, blue and UV regions and form the basis of white LEDs.

This is a hugely important distinction that was beyond the understanding of one blogger who wrote: “Given the increasing usage of GaAs, the main constituent in LEDs…there may be significant environmental concerns as related to their disposal… arguments that LEDs are more environmentally friendly than fluorescent lights containing mercury may be totally specious.” We can dismiss this as ill-informed rubbish, but wouldn’t it be better if we had some concrete data to throw back?

This is where the US DOE’s Life Cycle Analysis for Solid-State Lighting will come into its own. As described on page 21, the DOE has commissioned a study looking at the energy and environmental aspects related to the manufacturing, use and disposal or recycling of LEDs and SSL products.

LED manufacturing involves numerous steps, often with low yield, that consume some pretty nasty chemicals as well as lots of energy. The cost and environmental issues are dealt with by the LED makers, and reflected in the prices they charge. But that won’t satisfy the environmental lobby. So far, no-one seems able (or willing) to figure out how much energy is consumed by LED manufacturing compared with other light sources. It would be great to be able to say that LED manufacturing is more environmentally friendly, while also resulting in products that consume less energy. Let’s hope the DOE study yields the right results.