TABLE 6.7 Suggested Design to Be Used in Future RECS to Assess Lighting Energy Consumption and Usage Patterns

Number of lamps used less than Hi/day: Incandescent Halogen Compact Fluorescent Lamps Linear Fluorescent HID LED Other
Basement(s)
Balhroom(s)
Bedroom(s)
Closet(s)
Dining Room(s)
Exterior(s)
Garage(s)
Hall(s)
Kitchen(s)
Laundry / Utility Room(s)
Living / Family Room(s)
Office(s)
Other

NOTE: Similar tables using other usage intervals (1 to 4 h/days, 4 to 12 h/days, and more than 12h/day).

rate of the consumer. The latter is in general higher than the market rate and the social discount, both utilized in analyses of public investment (Azevedo et al., 2009; Frederick et al., 2002). The committee employed two scenarios for daily usage of lights: 3 h/day and 10 h/day. The committee selected these two usage scenarios for two reasons: first, because they are representative of average daily usages in the residential and commercial sectors, and second, the results are found to be very sensitive to the number of hours of use. For each scenario, it is assumed that a 60 W incandescent lamp would be replaced by another lighting technology while the same energy service is provided (850 lumen). The level of the energy service and the baseline power for the incandescent lamp does not change the overall results for this assessment.

The committee assumed efficacies, lifetime, and cost per thousand lumen values shown in Table 6.8. The committee used the figures from DOE (2011) for efficacy and lifetime of warm and cool LEDs, and scaled them so that for year 2012 they are in reasonable alignment with the efficacies and lifetimes of LEDs that can currently be purchased by consumers in retail stores. These same scaling factors were used for years 2015 and 2020, resulting in the following weighting factors for cool and warm LEDs: lifetime factor of 0.5, efficacy factor of 0.51, and a markup factor for price of 3. This further translated into lifetimes and efficacies for LEDs that are half of the goals reported by the SSL roadmap, and capital expense costs per thousand lumen that are three times what is reported in the SSL roadmap.

The results of the analysis in the 3 h/d usage scenario are shown in Figure 6.5 and for the 10 h/d scenario in Figure 6.6.

TABLE 6.8 Assumptions Used in Calculation of Cost in Figures 6.5 and 6.6

Efficacy (lm/W) Lifetime (h) Lamp Cost ($/lamp) Service Cost ($/thousand lm)
Incandescent 14 2,000 0.5 0.5
Compact fluorescein lamp (CFL) 69 8,000 4.4 4.3
Fluorescent tube (Tl 2) 69 5,000 2.0 2.0
Fluorescent tube (T8) 92 12,000 2.0 2.0
Fluorescent tube (T5) 104 20,000 2.0 2.0
Solid-state lighting (system level, warm white) 2012 72 25,000 23.0 22.5
2015 103 25,000 6.7 6.6
2020 129 25,000 3.1 3.0
Solid-state lighting (system level, cool white) 2012 90 25,000 18.4 18.0
2015 114 25,000 6.1 6.0
2020 132 25,000 3.1 3.0


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