Among existing and emerging technologies to recycle spent lithium-ion batteries (LIBs) from electric vehicles, pyrometallurgical processes are commercially used. However, very little is known about their environmental and energy impacts. In this study, three pyrometallurgical technologies are analyzed and compared in terms of global warming potential (GWP) and cumulative energy demand (CED), namely: an emerging direct current (DC) plasma smelting technology (Sc-1), the same DC plasma technology but with an additional pre-treatment stage (Sc-2), and a more commercially mature ultra-high temperature (UHT) furnace (Sc-3). The net impacts for the recovered metals are calculated using both “open-loop” and “closed-loop” recycling options. Results reveal that shifting from the UHT furnace technology (Sc-3) to the DC plasma technology could reduce the GWP of the recycling process by up to a factor of 5 (when employing pre-treatment, as is the case with Sc-2). Results also vary across factors, for example, different metal recovery rates, carbon/energy intensity of the electricity grid (in Sc-1 and Sc-2), rates of aluminum recovery (in Sc-2), and sources of coke (in Sc-3). However, the sensitivity analysis showed that these factors do not change the best option which was determined before (as Sc-2) except in a few cases for CED. Overall, the research methodology and application presented by this life cycle assessment informs future energy and environmental impact assessment studies that want to assess existing recycling processes of LIB or other emerging technologies. This article met the requirements for a gold–silver JIE data openness badge described at http://jie.click/badges.

Purpose: Microalgae-derived biofuels are considered a low-carbon alternative to fossil fuels. Nevertheless, as with all biofuels, there is still uncertainty around their sustainability. Most life cycle assessments (LCA) of microalgae biofuels so far used lab-based, scaled-up lab experimental data or data from the scientific literature. This article, provides evidence and analysis, undertaking an LCA using real-world data from an industrial facility that uses a combination of photobioreactor and fermenter systems. Methods: The current well-to-wheel LCA study aimed to compare the environmental impacts of microalgae biodiesel production—under different energy regimes—and with petroleum-derived diesel. The functional unit was considered as “combustion of 1 MJ (Lower Heating Value) of algal biodiesel in an internal combustion engine (as B100)”. This LCA study considers the environmental and energy impacts from the construction of the facility, as well as those impacts from the operation of the facility. The foreground LCI data was collected from a real-world one-hectare microalgae production pilot facility. ReCiPe, IPCC AR5 (GWP100 and GWP20) and Global Temperature Potential (GTP) were implemented to assess the life cycle environmental impacts. Results and discussion: The assessment shows that when infrastructure is included, microalgae-derived biofuels are not yet favourable over petroleum-derived fuels on GWP100, and this becomes worse over shorter timescales. In terms of climate change (GWP100), whilst 1 MJ (LHV) of fossil-derived diesel would emit 8.84 × 10⁻² kg CO₂eq, 1 MJ of microalgae-derived biodiesel from a solar photovoltaic powered facility would emit 1.48 × 10⁻¹ kg CO₂eq. To be equal to petroleum-derived diesel in terms of GWP100, or perform better, productivity of the microalgae production system needs to be improved as the most effective solution. The results also showed that electricity and infrastructure were major sources of environmental impacts, as well as the yeast used within the fermenter. Moreover, it takes 0.99 MJ of direct energy per 1 MJ of microalgae biofuel produced, similar to the fossil fuel industry for 1 MJ of diesel. Conclusions: Using infrastructure and operational models, the study shows that the facility does not compare well with petroleum-derived diesel unless productivity can be increased. Productivity improvements, be it through improvements to microalgae strains or improved photobioreactor designs, should be a priority to ensure microalgae become a sustainable fuel feedstock. Electricity use should be reduced as well, again, through improved cultivation system designs. In terms of the current system, the high impacts of yeast should be addressed, either through co-locating yeast production or through ensuring specific sources with lower impacts. Extracting lipids will effectively waste some high-value products, whilst the waste can be expected to be a mixture of unextracted lipids, polysaccharides or fibre, some proteins and minerals. It is also shown that harmonisations of the assessments are needed for future studies and real-world operation facilities to conclusively decide if microalgae should be used as fuel or if they would be better used for other products, such as feed or high-value products.

Material efficiency (ME) strategies are pursued by governments and companies to reduce environmental emissions, improve supply chain resilience, and enhance cost competitiveness. Material flow analysis (MFA) methods are useful to quantify raw material stocks and flows and assess the potential impacts of ME strategies. Although the popularity of MFA methods is increasing, there are methodological limitations that hinder its use as a decision support tool for prospective assessments. To overcome some of these, MFA is increasingly integrated with other methods from different research fields. This paper categorizes integrated MFA methods by identifying and explaining the methods and their applications. A semi‐structured literature review screened a wide range of methods integrated with MFA prospective analysis and evaluated their applications from 158 studies. This showed that integrated MFA can be used to: (1) include economic, social, and environmental layers; (2) improve the technical foundation of MFA by including entropy and exergy analyses and process engineering methods; (3) include economic mechanisms and link the economic system to the material system; and (4) improve the representation of materials in existing methods and models. Our research demonstrates that integrated MFA should be a central method in planning and designing ME strategies for companies and governments. This paper provides an important knowledge base of integrated MFA methods and creates a discussion point on MFA, where the research field is currently at or indeed where it could be heading in the future, that is, “Quo Vadis” MFA.