A recent story in Greenwire (subscription required) highlighted a debate over the benefits of subsidizing compact florescent bulbs. When the California Public Utilities Commission released its evaluation of Pacific Gas & Electric's incentive program for CFLs last year, evaluators found it was difficult to determine the energy savings. Peter Miller of the Natural Resources Defense Council explains the problem: "...none of the complicated statistical analyses used to try to estimate the net-to-gross ratio [the number of CFLs that would have sold without the program] produced a useable result." In the end, they were forced to use their "best judgement," which meant a much lower estimate of savings.
Also, PG&E believes they over-estimated the lifespan of an average CFL bulb when they created the program. They're finding the number is closer to 6.3 years instead of 9.4 years, which also lowers their estimated savings. As a result, some have questioned the effectiveness of the program and whether incentives are worth the investment.
Miller's analysis gives an in-depth look at California's situation. In the Pacific Northwest, we take a different approach. The Council's Regional Technical Forum is an advisory committee established in 1999 to develop standards to verify and evaluate efficiency savings. The RTF's analysis of CFL savings and lifespan estimates that the average life of a CFL is 5-6 years and that 1 in 3 lamps sold will be stored. Using the RTF's more accurate estimate would have helped lessen the gap between the projected and actual savings. "Had they used our numbers, they would be in less of a fix," says Tom Eckman, conservation resources manager for the Council.
"Because California utilities can only claim 'net' savings," says Eckman, "the folks who evaluate the programs have to estimate how many CFLs would have been purchased if the utilities hadn't offered incentives. This means they have to 'measure' what happened in an alternate universe, and not surprisingly, there could be some disagreement over their findings."
"We just try to measure how many total CFLs got installed and not fret over a fictional world," notes Eckman.
And so, as the Greenwire story concludes, "Researchers for the utilities commission plan to overhaul future incentive programs in an effort to evaluate utilities' success based on their technology installation rates instead of direct energy savings."