The cradle to gate life-cycle assessment of thermoelectric materials: A comparison of inorganic, organic and hybrid types

Using thermoelectric generators to convert waste heat into electricity is a renewable alternative to fossil energy sources. As thermoelectric materials are the main element of thermoelectric generators, so far numerous studies have attempted to optimize their energy conversion efficiency. However, no single study to date has examined their life cycle impacts, whilst it is the most important feature of any renewable technology. Accordingly, the aim of the present study is to assess the life cycle impacts of thermoelectric materials at their production stage (cradle to gate) using a life cycle assessment tool called GaBi v.4.4. Thus, the thermoelectric materials were categorized into inorganic, organic, and hybrid types. The five investigated impact categories were resource consumption, emission, waste, primary energy demand, and global warming potential. The results confirmed that the inorganic type caused significantly greater environmental impacts than the other two types. The only inorganic exception was Bi2Te3 that its environmental impact was by far the lowest among all the studied thermoelectric materials. Notably, the inorganic type caused major harm to the environment due to its extremely energy-intensive manufacturing process. However, the core environmental drawback of the organic and hybrid types was driven from their raw materials supply.