The benefits of sustainable lighting appear to be relative. There has been an evolution of lighting from the incandescent bulb to the compact fluorescent light (CFL) bulb, and now to the light emitting diode (LED) bulbs. Also, the European Union (EU) Ecodesign Directive and U.S. Energy Independence and Security Act have both lead the market and consumers to energy saving technologies which reduce greenhouse gas emissions. But it wasn’t until recently that I appreciated the realities of sustainable LED bulbs. Of course, we have all heard about the energy savings that CFLs and LEDs technologies have over incandescent bulbs, and this translates into economic savings for consumers over the lifespan of the bulb. http://www.designrecycleinc.com/led%20comp%20chart.html.
Yet some of the arguments for not buying incandescent bulbs might also redirect consumers away from CFLs, as compared to buying LEDs. For example, the focus of some articles has been whether consumers save money in the short-term or over the long-term. http://cleantechnica.com/2011/09/01/led-vs-cfl-which-light-bulb-is-more-efficient/. CFLs are less expensive than LEDs in upfront purchase costs. This article also notes that LEDs should be used in locations which are difficult-to-reach because they last about 3 times longer than a CFL, but the article also notes that CFLs are 3 times less expensive in initial upfront costs. However, the upfront-cost argument can just as easily be used to direct consumers to continue to buy the significantly less expensive incandescent bulbs, and perhaps this is why some consumers have stocked up on incandescent bulbs before these bulbs are no longer available on the market.
Yet in other articles, the focus does break down into energy efficiency/costs, environmental impact, and light output. http://www.designrecycleinc.com/led%20comp%20chart.html. As for energy efficiency/costs. LEDs are noted as using less power per lumen and reduce greenhouse gas emissions from power plants and lower electric bills. However, some articles indicate that CFLs and LEDs are comparable in power consumption. As for environmental impact, this chart notes that LEDs have about 10% of carbon dioxide emissions that incandescent do and less than 50% of that of CFLs. This article also focuses on toxicity and RoHS compliance based on the fact the CFLs carry mercury, yet neither LEDs nor incandescent bulbs have mercury. The popular media also question the quality and longevity of CFLs. http://www.popularmechanics.com/science/environment/will-led-light-bulbs-best-cfls-and-incandescents.
However, when turning to the peer-reviewed research literature, there continue to be sustainability issues with even the LED bulb. Lim et al. (2013) acknowledge that CFLs and LEDs are more energy-efficient than incandescent bulbs, but they also note that these lighting technologies require more metal-containing components. And perhaps the most significant observation is that “there is uncertainty about the potential environmental impacts of these components and whether special provisions must be made for their disposal at the end of useful life.” (Lim, Kang, Ogunseitan, & Schoenung, Potential environmental impacts from the metals in incandescent, compact fluorescent lamp (CFL), and light-emitting diode (LED) bulbs, Environ. Sci. Technol., 2013, 47 (2), pp. 1040–1047). Lim et al. found that “both CFL and LED bulbs are categorized as hazardous” due to excessive levels of metals, (e.g., lead, copper, zinc), while the incandescent bulb is not hazardous, so the “CFLs and LEDs have higher resource depletion and toxicity potentials than the incandescent bulb due primarily to their high aluminum, copper, gold, lead, silver, and zinc.” They concluded that “conservation and sustainability policies should focus on the development of technologies that reduce the content of hazardous and rare metals in lighting products without compromising their performance and useful lifespan.”
Yet even with these findings, choosing a sustainable lighting alternative is a relative choice. LEDs are dimmable and do not take time to become fully bright, which is a significant advantage for consumers with aging eyes. However, the most significant factor that made me change almost all my residential lighting to the more expensive LED lighting was my concern about toxic metals.
In the attached picture, there is a CFL bulb that was used for less than 1 year in my home. Looking closely, I noticed that mercury appeared to have been leaching out of the bulb at various points. This astounded me and made me want to go fully LED. Also, this past year, a U.S. company introduced more affordable LED bulbs in the 75 and 100 watt-equivalent range which provided brightness at either the 2700K (soft white) or 5000K (daylight) ranges, which was helpful for my aging eyes. These were recently being carried by the local hardware store at a more reasonable price. When I say “more affordable”, this is a relative term as LED bulbs are still considerably more expensive than CFLs and incandescent bulbs. At this time, I have moved most all my home lighting (over 50 bulbs) to the improved LED bulbs because of this “little” mercury issue, but having learned LED bulbs also have issues, I await the next technology which will lead to a more sustainable lighting alternative which show more mettle and less metal issues.