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UBC Theses and Dissertations

Life cycle assessment of net zero energy poultry housing Li, Yang


The egg industry worldwide has been expanding in recent decades, and the production of eggs has now reached a volume of 70 million tonnes. At the same time, increasing attention is being directed to understanding and improving sustainability outcomes in the egg industry based on life cycle thinking and related systems-analytical frameworks like life cycle assessment (LCA). To reduce life cycle environmental impacts in egg production, net zero energy (NZE) poultry housing has been proposed. An NZE layer barn pilot project is currently underway in Alberta, Canada, but it’s efficacy in improving sustainability outcomes compared to conventional layer barns is not well understood. The purpose of the research reported herein was to identify key design considerations for enabling achievement of NZE status in intensive, confined poultry housing systems, and to use environmental life cycle assessment to evaluate and compare environmental outcomes for NZE and conventional housing in the egg industry. To achieve NZE status in poultry housing, it was found out that housing system designers should focus on a combination of strategies respectively aimed at (1) reducing direct energy use via passive design, (2) improving direct energy use efficiency, in particular with respect to heating, ventilation and lighting, and (3) installing renewable energy generation systems. Any modifications to current technologies, however, should be based on careful consideration of the physiological requirements of poultry (such as ambient temperature, air quality, feed and water provision, etc.), local climatic factors, technical feasibility and availability of alternative technologies, and environmental as well as economic payback times. Based on the results of an ISO-14044 compliant, cradle-to-farm gate environmental life cycle assessment (LCA) of Canadian egg production with and without application of NZE housing, it was found that the largest share of life cycle environmental impacts for NZE poultry housing are attributable to the material production and construction phases. In contrast, they are highest for the operational phase in non-NZE poultry housing. The infrastructure-related life cycle impacts of NZE housing are more than offset by the much lower direct energy requirements that result, in particular, from superior insulation and use of a heat recovery ventilator. When the cradle-to-farm gate inputs to egg production are considered, housing infrastructure contributes a comparatively small fraction to total impacts, but direct energy inputs contribute a non-trivial share of impacts in non-NZE housing. The results for environmental impact payback time (eIPBT) calculations for use of NZE poultry housing with solar PV systems in different Canadian provinces indicate that the life cycle impacts of NZE poultry housing with solar PVs can be offset within the expected life span of the housing system, and hence generate net environmental benefits in most impact categories. In provinces with greener electricity grid mixes. Future research should incorporate analyses of economic feasibility and other social considerations for NZE poultry housing in order to provide improved decision support for both egg farmers and policy makers.

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Attribution-NonCommercial-NoDerivatives 4.0 International