Energy and eMergy assessment of the production and operation of a personal computer

- The computer production and recycling chains are investigated based on case studies.
- Indicators of computers environmental performance are developed and compared.
- Energy/emergy approaches are used as cost-benefit biophysical assessment tools.
- Recycling of materials is a mandatory option to decrease impacts and resource use.

Production of electronic devices (e.g., the day-by-day increasing number of computers and cell phones) requires energy as well as large and diverse amounts of materials, among which rare and strategic minerals. The extraction of such non-renewable resources is already a source of concern due to their limited availability and environmental impact. Identifying energy and materials costs over the entire production chain is, therefore, a priority in order to be able to suggest improvements that lead to optimizing resource use. On the other hand, the large and increasing numbers of these devices worldwide create additional concern about their end-of-life disposal, in order to prevent pollution of air, water and soil due to their degradation and leakage, if not properly managed. The end-of-life management of Waste Electric and Electronic Equipment (WEEE) has been the subject of heated debate over the past years. Their environmental impacts are so huge that they must be considered hazardous waste and must be regulated by a dedicated and specific legislation at international, European and national levels. Impacts may be decreased if WEEE are looked at a mine of valuable materials that, if properly exploited, can be re-introduced into the production chains with considerable economic and environmental advantages (and less extraction from mines).In this study, an energy assessment is performed to examine the energy costs of desktop and laptop computers from raw materials acquisition to manufacturing and use. Two options are explored, namely the use of primary materials and conventional fossil energy sources as well as an alternative scenario that uses recycled materials and renewable resources, in both production and use phases. Since, however, the environmental quality of renewable and non-renewable resources (their availability, renewability, regulatory role within ecosystems' dynamics) depends on the work performed by nature for their generation at the scale of biosphere, an eMergy assessment (i.e. an evaluation of the environmental support at the largest scale of biosphere) was also performed in order to explore the sustainability of reuse, recycling and recovering patterns.Calculated performance and sustainability indicators refer to the production and use of a desktop computer compared to a laptop computer, with focus on both production and use phases. In order to make comparison easier, not only reference is made to one computer as final product, but also to its computing performance (FLOPS, floating-point operations per second), a concept applicable to all computer models.