In the April 2012 issue of ELECTRICAL CONTRACTOR, we challenged the presumption that light-emitting diode (LED) lighting is maintenance-free. We found that, while it produces significant maintenance benefits over conventional technology, it must be maintained, though it requires rethinking of some aspects of how that service is performed.
Another presumption is that LED lighting is more energy-efficient and environmentally friendly than conventional technology. For the owner, this is generally true; up to 80 percent energy savings can be realized in certain applications, such as replacing incandescent lamps with LED replacement lamps. End of story?
The answer becomes uncertain beyond the point of use, considering total energy cost and environmental impact, including product manufacturing and shipping. So, the Department of Energy (DOE) produced two studies, which confirmed LED replacement lamps are more energy-efficient and environmentally friendly than both incandescent and compact fluorescent lamps (CFLs).
“Review of the Life-Cycle Energy Consumption of Incandescent, Compact Fluorescent and LED Lamps” (February 2012), is based on an analysis of 10 existing life-cycle assessment studies. The DOE reported two major findings.
Most lamp energy consumption occurs during actual use. The DOE estimates 90 percent of average total life-cycle energy consumption is during the product’s operating phase. Just 7–9 percent is consumed during manufacturing and less than 1 percent during transport. As a result, the average LED lamp uses 75 percent less energy than the average incandescent, based on an assumption that the average LED replacement lamp’s long-rated life is equivalent to about 22 incandescent lamps. Compared to compact fluorescent lamps, it’s pretty much a wash, based on an assumption the average LED replacement lamp’s life is equivalent to three CFLs.
The second study, “Life-Cycle Assessment of Energy and Environmental Impacts of LED Lighting Products” (June 2012), is based on analysis of more than 25 life-cycle assessment studies. It evaluates total environmental impact for typical competitive 12.5-watt (W) LED replacement lamps (Philips EnduraLED), 60W incandescent lamps and 15W CFLs (each producing about 850 lumens in light output), including the energy and natural resources needed for manufacture, transport, operation and disposal. Fifteen separate impacts were considered in the analysis of environmental footprint, including the potential to increase global warming, use land formerly available to wildlife, generate waste, and pollute air, water and soil.
Similar to the previous study, the DOE found the biggest effect occurs during lamp operation, making LED replacements and CFLs more environmentally friendly than incandescent lamps. In fact, environmental impact is reduced by three to 10 times by using these lamps instead of incandescent technology.
Specifically, LEDs’ largest environmental impact is energy use, which represents an average 81 percent across the 15 measures. The second most significant impact is raw materials used in manufacturing, accounting for an average of 16.8 percent. Manufacturing is just 2.3 percent and transport and disposal each less than 0.1 percent.
LED replacements and CFLs are similar in energy consumption, with the difference in environmental performance being largely determined by energy and resources consumed during manufacturing. LED replacement lamps were found to cause slightly less environmental harm than CFLs in all but one of the 15 measures studied, with the exception being disposal generation of hazardous waste. This is because LED replacement lamps contain a heat sink—a component attached to the bottom of the lamp that draws and dissipates heat from the LEDs, preventing overheating and a subsequent reduction in light output. This component is made of aluminum, which is energy-intensive to mine and creates byproducts that must be disposed as hazardous waste.
LED environmental performance is expected to improve due to technological and manufacturing improvements, widening the gap with CFLs. The main reason is LED efficiencies are expected to increase, reducing heat generation and, consequently, the size of the required heat sink. In contrast, CFLs are not expected to change significantly in the near future. By 2017, the DOE estimates the average LED replacement lamp will have 50 percent less environmental impact than today’s lamp and 70 percent less than today’s CFL.
Combined, these studies, which can be downloaded at www.ssl.energy.gov/tech_reports.html, suggest LED replacement lamps are more energy-efficient than CFLs and incandescent lamps across the life cycle, and have less impact on the environment in most key measures. Again, this performance advantage is expected to continue to improve in the future.
However, the studies do not cover one environmental performance aspect, which is hazardous materials (beyond the waste issue mentioned here). The DOE is planning a third study, which will examine the amount of hazardous materials that exist in LED replacements, CFLs and incandescent lamps and whether those materials are present in levels that exceed federal and California waste disposal regulations.