Preliminary Comparative Life-Cycle Impacts of Streetlight Technology

Abstract

As part of a streetlight-retrofitting project in Pittsburgh, this study performed a cradle-to-grave life-cycle assessment of four lighting technologies: the widespread high-pressure sodium and metal halide lights, and the newer and more efficient induction and light-emitting-diode technologies. The study used a hybrid life-cycle-assessment approach to build life-cycle models for the various technologies, including manufacturing and installation data for process models and energy supply and input-output data to complete life-cycle models. Three different electricity scenarios were used to examine the sensitivity of the impacts to changes in energy supply: the United States average mix, the regional mix for the ReliabilityFirst Corporation region, and a scenario with 100% wind power. The results show that for all technologies, the impacts of electricity in the use phase dominates the results. Because of their lower wattage, light-emitting diode (LED) and induction technology perform favorably and similarly. With anticipated improvements in technology, however, LEDs are expected to be more efficient than induction in the near future and have lower environmental impacts by the time that Pittsburgh and other cities buy and install lights as part of these streetlight projects, which have the potential to show large cost and emissions savings.