Purpose: Aluminium industry emits around 1–2% of the world’s total greenhouse gas emissions. Up to one-third of those are linked to the thermal energy consumed during its initial process: the alumina refining (Bayer process). Previous studies consider the Bayer process a single stage despite its being made of several reaction stages. This work presents a disaggregated energy analysis of the Bayer process that facilitates to find relationships between the main variables in regular alumina production and the environmental impacts. Methods: Two different thermodynamic simulations of the Bayer process were carried out using Aspen V11 software. The results of these simulations were validated with referenced data, and afterwards, they were used to perform a life cycle assessment. ISO 14040 and 14,044 standards were followed during the analysis. LCA was implemented on SimaPro 9.0, and ReCiPe 2016 Midpoint (H) method was used to calculate environmental impacts. The influence of bauxite mineral form, type of fuel (energy input), and the distance from the mine to the plant was analysed throughout the study. Results and discussion: As expected, the type of fuel was revealed as the most crucial factor in the environmental impact of alumina production, with potential savings of up to 75.5% of CO₂-equivalent emissions. Nonetheless, the tendency is diverse for other indicators, such as marine eutrophication or terrestrial acidification. On the other hand, while bauxite transportation always has the same impact on the different environmental indicators, bauxite mineral form affects differently depending on the fuel, causing variations in the CO_2-eq emissions from 7.7 to 51.3%. Conclusions: Results indicated that the electrification of heat-demanding processes and the use of renewable power is the most effective approach for reducing environmental impacts. This strategy, however, must be considered in combination with others, as interdependent effects exist on the type of mineral used. These results provide strong evidence of the potential for environmentally friendly strategies in the metal industry, including new processes, alternative fuels, or mineral switching to promote more sustainable aluminium production.

This paper demonstrates how to achieve energy savings in the construction and operation of buildings by promoting the use of life cycle assessment techniques in the design for new buildings and for refurbishment. The paper aims to draw on the application of a specific methodology for low energy consumption, integrated planning, environmental performance evaluation of buildings, and design for sustainability and LCA techniques applied to buildings. The ENergy Saving through promotion of LIfe Cycle assessment in buildings (ENSLIC) methodology based on LCA for use in an integral planning process has been promoted to stakeholders who require a means to optimize the environmental performance of buildings. Feedback from the stakeholders has facilitated the creation of simplified LCA guidelines, a systematic approach guiding the user through the alternative options regarding software choices, their strengths and weaknesses, the databases available, the usefulness of different indicators, aggregation, definition of limits and options for simplifying the process. As a result, this paper presents the applied results of a case study where this methodology is implemented serving as an energy savings evaluation tool for decision makers, end-users, professionals involved in the different stages of construction, etc. Finally, it is demonstrated how LCA can facilitate comparisons between different buildings, showing the influence of all variables on a building’s life cycle environmental impact and showing the potential for energy savings. Removing market barriers to sustainable construction is actually stricter and this is good news for promoting higher energy efficiency in buildings.