Life cycle assessment of electricity transmission and distribution-part 2: transformers and substation equipment

The purpose of this paper is to characterize the environmental impacts of equipment used in power transmission and distribution. This study is divided in two parts, each addressing different main components of the electrical grid system. This part is concerned with the impacts of transformers and substation equipment while in part 1 a similar analysis is presented for power lines and cables. The method used here is process-based life cycle assessment. Ecoinvent v 2.2 is used as a background dataset, and the results are obtained with the impact assessment method ReCiPe Midpoint Hierarchist perspective (v1.0). The average European power mix is used to model the electrical energy required to compensate power losses in the electrical equipment. Assuming a European power mix, results for transformers indicate that power losses are by far the most dominant process for almost all impact categories evaluated here, contributing at least 96% to climate change impacts. An exception is the category of metal depletion, for which production of raw materials is the most relevant process. Within infrastructure-related impacts, the production of raw materials is the most important process. Recycling shows benefits for most impact categories. For some substation equipment using sulfur hexafluoride (SF6), climate change impacts due to SF6 leakages surpass impacts due to losses. The results suggest that improvements in component efficiency-reduction of power losses and reduction of SF6 gas leakages in gas-insulated equipment-would significantly contribute to decreases in overall component impacts.