Critical review on life cycle inventories and environmental assessments of LED-lamps

Resource scarcity, hazardous waste, and climate change are the driving forces for developing energy efficient and low-toxic lighting sources. Currently, solid state lighting based on lightemitting diodes is expected to become the most dominant lighting technology of the future, mostly driven by its advantage with respect to energy efficiency. Parallel to the ongoing development of light-emitting diode-based lighting sources, a number of single case and comparative life cycle assessment studies of LED-lamps and components in varying study settings were carried out. However, these studies mostly rely to specific lamp designs, which limits general conclusions. This work includes a summary of the global market of lighting and LED-lamp technologies, followed by a comprehensive review and comparison of published life cycle assessment studies. In addition, we take also some aspects, which are relevant for the well-being of an end-user and which are usually not treated in life cycle assessment studies, like glare and health issues, into consideration. A critical interpretation of the assumptions and outcomes of these studies is given and questions that remain unsettled and therefore should be addressed in future studies are discussed.