June 3, 2014…The US. Department of Energy’s CALiPER program has released Report 21.3 as part of a series of examinations of linear LED lamps. Report 21.3 addresses as series of life-cycle cost simulations that compared a two-lamp troffer using LED lamps (38W total electricity consumption) or fluorescent lamps (51W total electricity consumption) over a 10-year study period. The LED lamps were assumed to produce similar light output and light distribution when mounted inside the troffers. The DOE points out less than a third of the products tested in the series of reports have the same output as their fluorescent counterparts. The DOE made this assumption for simplicity’s sake. The DOE says that in the near future output equivalence may be more generally achievable with SSL products.
Determining the cost-effectiveness of a given LED system for a given site requires the examination of many factors. The report focused only on the initial cost of the lamp, its energy consumption, and the system lifetime/replacement needs. For the simulation, variables included LED system cost (two lamps plus separate driver if required totaled $40, $80, or $120), annual operating hours (2,000 hours or 4,000 hours), LED installation time (15 minutes or 30 minutes), and melded electricity rate ($0.06/kWh, $0.12/kWh, $0.18/kWh, or $0.24/kWh).
Readers can use the tables to look up combinations of factors that most closely resemble their own situation. A simple estimation between values in the tables can aid in making rough assessments of economic feasibility for projects.
Use of older, inefficient ballasts can reportedly add up to 4 Watts to T8 power consumption. The DOE notes that This may not be critical in areas where the cost of electricity is very low or in a facility with low operating hours, but in most applications the DOE report advises considering upgrading to a higher efficiency ballast and T8 lamps.
The DOE found that lamp costs varied widely depending on how and from whom the LED lamps were purchased. Prices also varied regionally. The two lamp troffer in the simulation ran $30 for traditional fluorescent and $40, $80, or $120 for the LED-based lamps. The simulation looked at fluorescent lamp and ballast cost. The Fluorescent lamps also included a $1.00 recycling fee at the end of its lifetime.
The DOE found that in general, while their initial cost premium remains high in comparison to conventional fluorescent lights, linear LED lamps are more likely to be cost-effective when electric utility rates are higher than average, hours of operation are long, and if their installation time is shorter.