Tuesday, March 24, 2009

Low Hanging Fruit: Ripe for the Pickin'

Our efforts to reduce carbon emissions will undoubtedly utilize many different strategies. Pacala and Socolow of the Princeton Environmental Institute first illustrated the concept of stabilization wedges in 2004, in which they identified a desirable CO2 emissions rate and prescribed various existing technologies we can use to achieve emissions reductions (1). The wedge concept reiterates the important, and sometimes overlooked idea, that a diverse array of technologies and practices are necessary, and that we should emphasize the use of existing technologies to make emissions reductions. One of the wedges I would like to discuss is the Efficient Building wedge, specifically lighting as it is the lowest hanging fruit of them all.

The inefficiency of incandescent light bulbs is well known; about a 5% efficiency with the rest wasted as heat. Many countries have passed regulations to phase out incandescent bulbs, Australia, Brazil, Switzerland, U.S. (by 2014), and recently the EU (by 2012). The substitute lighting of choice for the majority of residential and commercial applications are CFL's. Lasting 10 times longer than incandescents (10,000 hrs) and using 75% less energy, CFL's will greatly reduce energy use and carbon emissions(2). But why stop there?

The promise of cost competitive light emitting diodes (LED's) may be closer. LED's boast even greater energy efficiencies and life spans (45,000 hrs) than CFLs, but up to this point have been prohibitively expensive. Recent production breakthroughs, noted in the latest Economist, may greatly reduce the cost of LED's. The breakthrough involves using cheaper silicon wafers instead of expensive sapphire-based wafers. Using silicon wafers means a lower cost for materials, and a production process that can utilize more economical 6 inch wafers and more common fabrication equipment(2).

The potential future energy savings of switching to LED's has been noted by the DOE. They estimate that LED's can reduce the electricity demand of lighting by half and avoid adding 130 new power generation facilities. DOE's Next Generation Lighting Initiative, started in 2003 and funded through 2011 with $450 million, sole objective is to "research, develop, and conduct demonstration activities" "based on white light emitting diodes" (3). The goal is to make LED's cost competitive with incandescents and CFLs, while maintaining desirable lighting qualities, by 2011. Identified by DOE as a major obstacle to meeting this goal is the cost of materials and manufacturing. Perhaps the recent production breakthrough is on their radar, and hopefully the commercialization of these LEDs is not far off. It would be ideal for LED commericialization to take place during the lighting replacments now mandated, instead of a second lighting renessiance further down the road.

(1) Pacala, 2004, Stabilization Wedges: Solving the Climate Problem for the Next 50 Years with Current Technologies, Science 305, 968, http://www.sciencemag.org/cgi/reprint/305/5686/968.pdf

(2) The Economist, 2009, A brilliant new approach, http://www.economist.com/science/displaystory.cfm?story_id=13315818

(3) EIA, 2002, Impacts of Energy Research and Development, http://www.eia.doe.gov/oiaf/servicerpt/erd/energy.html


Mark McCarthy said...

I agree that it would be ideal for LED lighting to be available for this transition, but it seems unlikely that this will happen. I attended a talk last year on energy efficiency that discussed the potential for LEDs, and it was posited that they would reach a commercial ready state between 3 and 30 years from that time, depending on various improvements in technology and price. There is still the problem of getting the light to be diffuse enough to be considered a replacement for traditional incandescent or CFL bulbs. I personally see CFL as an intermediary step, but a necessary one, because waiting for LEDs to be ready seems problematic at best.

Steven Meyers said...

You are right on to emphasis Building Efficiency. The "McKinsey Carbon Cost Curve" shows residential and commercial lighting to be the highest-return options for reduceing GHG emissions. LEDs are making a lot of progress, but their lumen levels are not quite at the level of CFLs or incandescents. In addition to the need to replace all incandescents, we need to focus on replacing the inefficient 4' T-12 lamps that exist in many commercial facilities. Many larger companies have replaced these lamps with more efficient T-8 or T-5 lamps. However, small businesses are still very inefficient and use T-12s. Therefore, maximizing the "efficiency wedge" requires not only a new technology (i.e. T-8, CFL, or LEDs), but also requires a business model and incentive system to catalyze the change to the efficient existing technologies. There is enormous potential to moving people to the "state-of-the-shelf" in addition to moving the "state-of-the-art".