Meta-analysis of the life cycle of small-sized power converters: a systematic review

Abstract

Purpose: The decarbonization of enabling technologies, such as power electronics converters, which supports the implementation of renewable energy, is the major research interest of this work, in a bid to produce an objective comparison of the environmental impact associated with the manufacturing and use of these technologies. This article aims to provide a comprehensive overview of the relevant literature, which has been selected on the life cycle assessment (LCA) for converters with respect to their environmental impacts, methods, and parameters, and investigates which research gaps are identified. The final goal is also to provide a first-of-its-kind background, useful for manufacturers ready to commit to sustainability, in finding current benchmarks to compare their products. Method: A meta-analysis or systematic review method was employed in this study to set the background knowledge and relevant works, assess quality studies, and explore heterogeneity (difference between the studies and combining their effects). Results: The results from the analysis showed a significant difference, ranging from 4.95 to 21.15gCO2eq/kWh for the solar inverters (2.5–10 kW reference size) and from 22.80 up to 143 gCO2eq/kWh for those of a WEC (wave energy converter of various sizes), with the upper values being consistently 5–6 times higher than the lower. These variations were primarily due to several factors, including (1) resource inputs and technology used; (2) geography; (3) transportation (supply chain); (4) manufacturing process/methodology; (5) sizing and capacity; (6) calculation methods; and (7) longevity. All of them have a significant impact on the results, thus potentially undermining any possible comparison unless clarifications, specific ranges, and conversion factors are specified. Conclusion: We conclude by showing that the use of standard LCA analysis and the quality of the assumptions in the calculations would be able to reduce the uncertainties in the GHG emissions recorded in the studies, and we show how to compare studies reporting diverse data and references in a meaningful way.