Achieving Sustainability with Technology: the Exceptional Case of Lighting

The electricity needed for lighting is in free fall and the reason is technology. As we discussed in the previous post, electricity used for residential lighting has (somewhat) unexpectedly begun to fall and is expected to continue to do so for the ensuing decades. Tentatively, we can conclude that neither changing consumer behavior nor saturated demand are the causes. The reason instead is the success of new lighting technologies.

We here at Achieving Sustainability are big believers that a Sustainable future ultimately relies on each of us as individuals and as societies transforming ourselves and that technology is at best neutral for Sustainability.¹⁾As an example recently in the news: the development of a replacement for CFCs helped make addressing the ozone hole a success story but the replacements (HCFCs) are powerful and increasingly problematic greenhouse gas--thus new technology has helped solve one problem but is contributing significant to another. But in the case of lighting there is no denying, that technology (and the policies pushing them) are driving a surge towards Sustainability.

Incandescent light bulbs are notoriously inefficient converting only 10% of the electricity they use into light. The easiest metric for comparing the efficiency of light bulbs is the lumens (a measure of light) produced per watt (a measure of electricity). The more lumens produced per watt the better. After over a hundred years of dominance by the revolutionary but inefficient incandescent bulb of Edison, new options have finally emerged. In the graph below it is easy to see the vast efficiency improvements offered by new technology.²⁾In theory LEDs will be able to turn 98% of electricity into lighting and the Department of Energy estimates that by 2030 their will be commercially available bulbs producing 200 lumens per watt.

 

As decade after decade we remained stuck with the woefully inefficient incandescent bulb, our homes enlarged and our desire to better light them grew, and thus the electricity needed inexorably increased as well. Recognizing the limits of the incandescent bulb, scientists developed fluorescent tubes which began to be deployed widely in the commercial sector by World War II but besides specific uses, e.g. public housing and some low-end apartments, fluorescent tube lighting never penetrated the residential market. I am sure this surprises no one, with their flickering and headache inducing illumination few people were tempted to change over from incandescent. And thus the reign of Edison's bulb continued.

A Light at the End of the Tunnel

In response to the oil embargo in the 1970s a compact spiral-shaped fluorescent bulb for normal sockets was invented but what we today call the CFL (compact fluorescent lamp) would not become commercially viable until the 1990s. In 1993 when the Department of Energy released their first report they spent a good deal of space demonstrating the energy savings of CFLs but at a price of $36 in today's dollars ($22 in 1993), and plenty of technical problems, no one was buying. This report also found that American households average around 30 light bulbs, which by 2001 had grown to 45 and electricity used for lighting continued to increase with no hope for change. Yet even though a report in 2010 found that the average number of light bulbs had now grown to 51, electricity used for lighting had already begun to fall.

 

Despite winning a Nobel Prize for their inventors,³⁾The trick was actually making blue LED light, which when combined with the long existing red and green LEDs, could produce the white light we look for to illuminate our homes. Congratulations to Isamu Akasaki, Hiroshi Amano and Shuji Nakamura. LEDs are not the cause of the decline we have seen over the last decade in residential energy use--their penetration is far too low. In fact they do not even appear in a measurable quantity in the latest residential lighting survey-thus their invisibility on the above graph. Rather, the increasing penetration of CFLs is clearly driving the decline despite the continuing increase in installed bulbs. This has caused a significant drop in the average wattage of residential bulbs from 63 watts in 2001 to 46 in 2010.

What is so exciting about this moment is that while CFLs begun to bend the curve downward, the arrival of LEDs has the potential to accelerate that trend and send levels of electricity usage for lighting to levels unimaginable even a decade ago.

The Series: Achieving Sustainability in Lighting

• For Lighting, Sustainability is within Reach: But is demand saturated?
• Achieving Sustainability with Technology: the Exceptional Case of Lighting"
• When will we be LED to Sustainable Lighting?
• Bush Era Law is Helping to Achieve Sustainability in Lighting
• A Vision for Sustainable Lighting