UPDATED: Life-cycle study examines total energy used in LEDs, CFLs, and incandescents
OSRAM and Siemens (which is the parent company of OSRAM) teamed up to do a life-cycle assessment of LED-based lights, specifically in comparison with incandescent and compact fluorescent lights (CFLs). To cut to the chase, the study found that over 25,000 hours, the total energy required — including manufacturing, use, and end-of-life disposal/recycling — for a 8W LED lamp as well as its equivalent in CLFs is about the same: About 700kWh. The total energy requirement for incandescent lighting is about 3,300 kWH. (The study assumes a 25,000 hour lifetime is one LED light, 2.5 CFLs, and 25 40W incandescent lights.) The energy used in manufacturing 1 LED light and 2.5 CLFs looks like it’s about 60 kWh for each, compared to about 275 kWh for the 25 incandescent lights.
OSRAM is headlining the study results as, “Life-cycle assessment proves how environmentally friendly LED lamps are,” but this is a bit of a straw dog. It’s good to know that the manufacturing of an entire LED light, not just the LED chip, doesn’t appear to have a hidden environmental impact, but the bottom line is that an LED light uses the same amount of energy as a CFL, and costs at least ten times as much.
Every time I ask for questions at one of our LED Workshops or for a lighting webinar, EDN readers ask for total pricing information and ROI for LEDs. We’ll explore this further at the next Workshop in Chicago on October 6. You can register here.
Although as an LED provider OSRAM is certainly a biased source, the study results appear reasonable. OSRAM and Siemens have invited three independent experts to verify the findings of the internal study. A summary of the study will be available in October at www.osram-os.com/life-cycle-assessment.
UPDATED: For those readers who questioned the high kWh of total energy used, which was greater than just multiplying the wattage of the light times hours used: The highest energy number (3300kWh in the case of the incandescent) is for the total energy required to manufacture, power, and dispose of the three types of lights. Here is a (barely legible) diagram of the steps included in the energy calculation by OSRAM:
The titles of the three "input" boxes on the left seem to be: "Input (raw materials, energy, etc)", "Input (energy, auxiliary materials, etc)" and "Input (energy source from power)." I’m guessing that "Input (energy, auxiliary materials, etc)" includes the energy used in creating, say, the heat sink required for the LED light.
For readers who question whether OSRAM included the environmental cost of mercury present in CFLs: That should be included in the recycling step. This study was done in Europe, where I understand recycling is more effective than in the US, and environmental concerns in general may be higher.