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Aluminum is one of the most used metals of modern civilization, but its production is responsible for multiple adverse environmental impacts mostly due to aluminum smelting and alumina refining. Previous life cycle assessments (LCAs) have aggregated alumina refining into a single global process even though refining processes are highly spatially differentiated and alumina is highly traded. Our work improves on existing LCAs of primary aluminum by including temporal and spatial differentiation in alumina refining and aluminum smelting and trade of alumina and primary aluminum ingots. We build country‐level impact factors for primary aluminum ingot production and consumption, with the spatial distributions of environmental impacts, from 2000 to 2017, by combining a trade‐linked multilevel material flow analysis with LCA using six midpoint categories of the ReCiPe method. Climate change impacts of primary aluminum production range from 4.5 to 33.6 kg CO2 eq./kg. We then estimate the life cycle production‐ and consumption‐based environmental burdens of primary aluminum ingot by country. High spatial variations exist among impact factors of primary aluminum production. Aggregating the alumina refining processes into a single process may cause important deviations on the impact factors of primary aluminum ingot production (up to 38% differences in climate change impacts). Finally, we estimate the climate change impacts of worldwide primary aluminum production at 1.2 Gt CO2 eq. in 2017 and untangle their spatial origins, localized at 70% in China. Overall, we show the importance of spatial differentiation for highly traded products that rely on highly traded inputs and offer recommendations for LCA practitioners. This article met the requirements for a gold‐gold JIE data openness badge described at http://jie.click/badges. [ABSTRACT FROM AUTHOR]

Two different sized hydropower projects in China, one with a capacity of 44 MW and the other of 3,600 MW, were examined through life-cycle assessment (LCA) from the perspective of both sustainability and environmental impact and the influence of project scale. Using the economic input-output based LCA approach, energy use and greenhouse gas (GHG) emissions were quantified. The resulting energy payback ratios were found to be 7 and 48, whereas the normalized GHG emissions were 44 and 6 gCO2 equivalent per kW h of electricity production, both in favor of the larger project. Compared with published data on other renewable and nonrenewable options, temperate hydropower, particularly large hydropower, is indicated as an efficient electrical source with relatively low GHG emissions. [ABSTRACT FROM AUTHOR]

To support more sustainable development of a region, decision support tools must consider local and global systems level impacts on the economy, environment, and society. Through the development and application of "economic input–output water resources" models for Beijing, China for the years 1985, 1990, and 1992, historical trends related to the economy structure and its water use are investigated. The study finds that the economy of Beijing and water use are highly concentrated in agriculture and heavy industry, but this intensive water use is indirectly reflected in the production of most other goods and services throughout the economy because of the interrelationships among various sectors of the economy. In spite of progress during the time period observed (e.g., between 1985 and 1990 the output of the economy doubled, but water consumption increased only 12% partly because of a significant increase in the price of water in 1988) and given the seriousness of water resources issues in the region, it is critical that future regional development make progress toward a more water-efficient economic system. [ABSTRACT FROM AUTHOR]

A method combining life cycle assessment (LCA) and real options analyses is developed to predict project environmental and financial performance over time, under market uncertainties and decision-making flexibility. The method is applied to examine alternative uses for oil sands coke, a carbonaceous byproduct of processing the unconventional petroleum found in northern Alberta, Canada. Under uncertainties in natural gas price and the imposition of a carbon price, our method identifies that selling the coke to China for electricity generation by integrated gasification combined cycle is likely to be financially preferred initially, but eventually hydrogen production in Alberta is likely to be preferred. Compared to the results of a previous study that used life cycle costing to identify the financially preferred alternative, the inclusion of real options analysis adds value as it accounts for flexibility in decision-making (e.g., to delay investment), increasing the project's expected net present value by 25% and decreasing the expected life cycle greenhouse gas emissions by 11%. Different formulations of the carbon pricing policy or changes to the natural gas price forecast alter these findings. The combined LCA/real options method provides researchers and decision-makers with more comprehensive information than can be provided by either technique alone.