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MPhil in Engineering for Sustainable Development

global challenges, engineering solutions

Studying at Cambridge


Aaron Junjian Zhang

Life Cycle Sustainability Assessment as a Tool for Sustainable Product Development - A Case Study of a Bamboo Bicycle

While bicycles are regarded as a sustainable transportation mode, few studies have been conducted to assess the sustainability of the raw materials which are used in the production process. Nowadays, aluminium is the dominant raw material used to manufacture bicycle frames in the commuting category of cycling. The extraction, processing and recycling of aluminium have led to negative environmental impacts and large amounts of energy consumption, with the frame of a bicycle embodying up to 86% of the bicycle’s total energy consumption. In this case, material selection holds the key to significantly improving the sustainability of a bicycle. This dissertation explores the potential to construct bicycle frames in Kenya using regionally available materials. Kenya is chosen for its access to ports and relatively high manufacturing capabilities compared to the region. Bamboo has been found to be a potentially sustainable alternative to replace aluminium in bicycle production. This case study involves a comprehensive life cycle sustainability assessment, consisting of an environmental life cycle assessment (LCA), life cycle costing (LCC), and social life cycle assessment (S-LCA), of bicycle frames manufactured from wild bamboo in Kenya compared with a common standard, an aluminium bicycle frame made in China. The study is formed around an end user based in the UK to validate the global competitiveness of the frames made in Kenya. The overall LCA concludes that material choice is the most significant factor in the carbon dioxide footprint and embodied energy for the two frames compared to other elements in the life cycle. Specifically, bamboo frames can be produced with one-sixth the energy and one-eighth the carbon dioxide emissions of an aluminium frame. This study concludes that the LCC of  making an equivalent basic bamboo frame in Kenya is £8.33, while the LCC of making an aluminium one in China (benchmark) is £19.74. Lastly, the S-LCA utilises a social hotspot database to reveal concerns in Kenya regarding child labour, minimum wages, hours worked per week, social protection expenditure, wellbeing and satisfaction with life, political stability, unemployment rates, and corruption for a holistic comparison. Ultimately, the LCA, LCC and S-LCA substantiate the validity of manufacturing bicycle frames from bamboo in Kenya for environmental, cost and social benefits as opposed to manufacturing them from aluminium in China. Further, the validity of this case contributes to the notion of decentralising the bicycle industry in general.