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This paper analysed and summarised the significant research outputs published on the environmental impact assessment of mining and mineral processing industries through life cycle assessment. The paper presents valuable insights in identifying the gaps, where should the focus be in the mining and mineral processing industries for a sustainable future. Mining and mineral processing industries have been the key focus of research in many countries due to its increasing sustainability concerns that affect global warming and climate change. Use of heavy equipment that consumes electrical energy, mechanical energy, and an enormous amount of process heat is a key contributor to the overall impacts in the industry. Due to the use of heavy equipment and associated energy consumption, these industrial sectors contribute notably to global warming, human health, ecosystems, and resources. Among the various environmental impact assessment tools which are widely used to identify sustainability indicators, life cycle assessment (LCA) is a well-justified approach among the practitioners and researchers. Though state of the art technological tools and resources are being used now a days, there is still a research gap in identifying the key mining processes which need to be the focus of attention. Renewable energy integration in the mineral processing sector and process heating from green energy sources is becoming the emergent field of research. The review results reveal, the assessment indicators in human health and ecosystems are key factors that are mostly missing in the previous studies which are crucial for people or community living nearby mining area. This review paper identifies the research gaps to the existing literature that can form the base for future research direction in the field of LCA and sustainable energy integration in mining and mineral processing industries. • A review based on life cycle assessment studies in mining and mineral processing. • 16 metal mining industries are reviewed. • Summarised key factors of environmental effects using LCA. • Future research directions are highlighted. [ABSTRACT FROM AUTHOR]

In the Chemical Process Industry (CPI) only hydrogen production from steam methane reforming produces more greenhouse gas emissions than light olefins production. Various solutions have been proposed to reduce the CO2 emissions from olefins production. It is not clear which solution is best, particularly when you consider other sustainability factors. In this paper we report the results of our cradle-to-gate life cycle assessment (LCA) of three highly promising solutions: a so-called low-emission steam cracking furnace, the electrically driven RotoDynamic reactor (RDR), and a blue hydrogen-fired furnace. Life cycle inventory data is obtained from a first principles model for steam cracking, validated with industrial data, and combined with data obtained from process simulation. Our study shows that if the electrical supply is grey then the RDR-based cracking process has a 41% higher impact on climate change than the reference base case, a conventional plant with state-of-the-art furnaces. The low-emission furnace is only 7.2% higher. When using a mixed electrical grid, like Belgium's, the climate change impact for the RDR is 1.5% higher and the low emission furnace is 6.6% lower. With a grid that uses fully renewable power generation the RDR solution is an impressive 27% lower than the base case and the low-emission furnace 17% lower. We also analysed the impact of firing the furnaces with blue hydrogen from (a) a conventional steam-methane reformer and (b) an innovative gas-heated reformer: both (a) and (b) using carbon capture and storage (CCS). The climate change impact is reduced by 8% and 18% respectively compared to the base case. Since the blue hydrogen solution uses very little electricity, the climate change impact is insensitive to the method of electrical power generation. • Prospective LCA of 3 promising steam cracking concepts has been performed. • RotoDynamic reactor results in 27% lower carbon footprint if powered by a "green" grid. • Low-emission furnace has a 16% lower carbon footprint in a "green" grid. • Low-emission furnace is preferable if the case of "grey" or mixed grid. • "Blue" hydrogen combustion allows a reduction of carbon footprint up to 18%. [ABSTRACT FROM AUTHOR]

A healthy diet depends on the daily intake of vegetables. Yet, their environmental impacts along the full supply chains are scarcely known. Therefore, this paper provides for the first time a comprehensive evaluation of the life cycle environmental impacts of vegetables consumed in UK. The impacts are assessed for 56 fresh and processed products produced domestically and imported from abroad, considering both the product and sectoral levels. At the product level, taking into account the market mix of fresh and processed vegetables for each vegetable type sold in the UK, asparagus has the highest per-kg impacts across most of the 19 impact categories considered, while cabbage, celery and Brussels sprouts are generally environmentally most sustainable. At the sectoral level, the annual consumption of 10.8 t of vegetables generates 20.3 Mt CO 2 eq., consumes 260.7 PJ of primary energy and depletes 253 Mt eq. of water. The majority of the impacts are caused by potatoes since they account for 56% of the total amount of vegetables consumed, with crisps and frozen chips contributing most to the total impacts. Importing vegetables grown in unheated greenhouses in Europe has a lower impact than UK vegetables cultivated in heated greenhouses, despite the transportation. The impacts of air-freighted fresh vegetables are around five times higher than of those produced domestically. Even processed products have lower impacts than fresh air-freighted produce. Packaging also contributes significantly to the impacts, in particular glass jars and metal cans used for processed vegetables. Other significant hotspots are open display cabinets at the retailer and cooking of vegetables at home. The results of this study will be useful for food manufacturers, retailers and consumers, helping to identify improvement opportunities along vegetables supply chains. Unlabelled Image • Life cycle impacts are assessed for 56 vegetable products consumed in the UK. • Asparagus has the highest impacts across most of the 19 impact categories considered. • Cabbage, celery and Brussels sprouts are environmentally most sustainable. • Vegetables consumption generates 20.3 Mt CO 2 eq. and depletes 253 Mt eq. water/yr. • Air-freighted fresh vegetables have five times higher impacts than UK-grown produce. [ABSTRACT FROM AUTHOR]

Biscuits are a major product category in the global confectionary sector. Despite this, their environmental impacts are poorly characterised. Therefore, this paper sets out to evaluate the life cycle environmental sustainability of the following widely-consumed types of biscuit, both at the product and sectoral levels: crackers, low fat/sugar, semi-sweet, chocolate-coated and sandwich biscuits with chocolate or vanilla cream. The results obtained through life cycle assessment demonstrate that, in addition to being healthier, low fat/sugar biscuits have the lowest impacts across most of the 18 categories considered. Chocolate-coated biscuits are environmentally the least sustainable. The most significant life cycle stage for all types is the raw materials production, causing 41%–61% of the total impacts, with flour, sugar and palm oil being the key hotspots. Replacing palm with rapeseed oil would improve five impacts but worsen another five, including a 34% increase in agricultural land occupation and marine eutrophication. Therefore, the cultivation and production of palm oil, rather than its replacement, should be targeted for improvements. The second most crucial stage is manufacturing, contributing up to 54% of the impacts, followed by transport with up to 35%. Reducing energy consumption by 25% in manufacturing would reduce primary energy demand by 8%–12%, fossil fuel depletion by 9%–12% and global warming potential by 6%–9%. The latter would increase by 55% if land use change related to cocoa was involved, despite a very small amount of cocoa in the biscuits (∼1%). The analysis at a sectoral level in the UK, the leading consumer of biscuits in Europe, reveals that biscuits contribute 7.4% of primary energy demand and 0.5% of greenhouse gas emissions of the whole UK food sector. These results can help guide manufacturers in mitigating the hotspots in the supply chain and consumers in selecting environmentally more sustainable biscuits. • The environmental sustainability of six types of biscuit is evaluated for the first time. • Low fat/sugar biscuits have the lowest impacts and chocolate-coated the highest. • Global warming potential of chocolate biscuits is 55% higher with land use change. • Flour, sugar and palm oil are the key hotpots, followed by biscuits manufacturing. • Biscuits contribute 7.4% of energy demand and 0.5% of GWP of the UK food sector. [ABSTRACT FROM AUTHOR]

The life cycle assessment (LCA) methodology is increasingly used to ensure environmental sustainability of emerging biofuels. However, LCA studies are usually not performed at the process design stage, when it would be more efficient to identify and control environmental aspects. Moreover, the long-term economic profitability of biofuels depends on future energy and climate policies, which are usually not considered in techno-economic feasibility studies. This paper combines the LCA method and a TIMES energy system model, to offer a simultaneous assessment of potential environmental impacts and market penetration under different energy and climate policy scenarios of emerging energy pathways. This combined approach is applied to butanol produced from pre-hydrolysate in a Canadian Kraft dissolving pulp mill. Indeed, the integration of biorefinery processes into existing pulp and paper mills has been identified as a promising avenue to maintain mills activities. It could increase and diversify revenues, keep the forestry-based communities alive, and potentially mitigate climate change by replacing fossil-based fuels or products. Results show that (1) the energy efficiency of the butanol production process is a critical aspect to consider in future design and implementation steps in order to make butanol a competitive fuel among all other alternative fuels, (2) with a 50% internal heat recovery, butanol has a role to play in the transportation sector under climate policy scenarios, and may have a lower carbon footprint than gasoline as estimated by a 2010 US EPA study, and (3) higher supply costs for feedstock might undermine the competitiveness of butanol on the medium term (2030), but probably not on the long-term (2050). This combination of assessment methods is replicable to analyze any types of emerging energy pathways in Canada and in other countries, and to help designing more sustainable forest biorefinery processes in other countries with important forest sector. [ABSTRACT FROM AUTHOR]

Abstract The use of biomass for production of chemicals is gaining interest because of its potential to contribute towards a reduction in greenhouse gas emissions and other environmental benefits linked to the substitution of fossil resources. But, conversely to biofuels, studies focusing on environmental impacts of biomass-derived chemicals are scarce. This paper uses life cycle assessment to evaluate the environmental sustainability of bio-ethylene from poplar produced by the following three thermo-chemical routes: direct and indirect dehydration of ethanol and production of olefins via dimethyl ether. The indirect route is the best option for most impact categories for all three allocation methods considered: system expansion, economic and energy basis. However, the dimethyl ether-to-olefins route has the lowest global warming potential. In comparison to ethylene produced bio-chemically from sugar beet, the thermo-chemical indirect route has lower impacts for all categories except human, terrestrial and freshwater toxicities. All three thermo-chemical alternatives show a significant reduction in global warming potential (up to 105% in the case of dimethyl ether-to-olefins) and depletion of fossil fuels when compared to conventional ethylene production from fossil fuels. However, the results also suggest that bio-ethylene produced by any of the three thermo-chemical routes would lead to a significant increase in most other impact categories relative to fossil fuels. Therefore, while trying to reduce greenhouse gas emissions, the overall environmental sustainability of bio-ethylene suffers from the increase in other environmental impacts. Highlights • Three thermo-chemical bio-ethylene processes are compared environmentally. • Indirect route is best for several impacts but the dimethyl ether is better for GWP. • Indirect route is better than 1st generation ethanol dehydration except for toxicities. • Net saving in GHG emissions of 44%–105% achieved compared to fossil alternatives. • However, other impacts are higher than for the fossil alternatives. [ABSTRACT FROM AUTHOR]

Hydrogen could be used as a ‘cleaner’ cooking fuel, particularly in communities that rely on biomass and fossil fuels, to reduce local pollution and related health effects. However, hydrogen must be produced using sustainable feedstocks and energy sources to ensure that local impacts are not reduced at the expense of other impacts generated elsewhere in the life cycle. To this end, this paper evaluates life cycle environmental impacts of renewable hydrogen produced in a proton-exchange membrane electrolyser using solar energy. The aim of the study is to find out if hydrogen produced in this system and used as a cooking fuel is environmentally sustainable in comparison with conventional cooking fuels typically used in developing countries, such as liquefied petroleum gas (LPG), charcoal and firewood. The results suggest that hydrogen would reduce the climate change impact by 2.5–14 times to 0.04 kg CO 2 eq./MJ compared to firewood (0.10 kg CO 2 eq./MJ) and LPG (0.57 kg CO 2 eq./MJ). Some other impacts would also be lower by 6%–35 times, including depletion of fossil fuels, summer smog and health effects from emissions of particulates, both locally and across the rest of the life cycle. However, some other impacts would increase by 6%–6.7 times, such as depletion of metals and freshwater and marine ecotoxicity. These are mainly due to the solar photovoltaic panels used to generate power for the electrolyser. In terms of the local impacts, the study suggests that hydrogen would reduce local pollution and related health impacts by 8%–35 times. However, LPG is still environmentally a better option than hydrogen for most of the impacts, both at the point of use and on a life cycle basis. [ABSTRACT FROM AUTHOR]

Life cycle assessment (LCA) is an important tool to evaluate environmental ‘hot spots’ in livestock systems and recommend production improvements. However, it is common for livestock LCA to investigate only a narrow subset of environmental impacts to simplify results for decision-makers, which makes it difficult to fully understand the tradeoffs among environmental impacts and identify the most relevant mitigation options. We completed a systematic review of the livestock LCA literature to better understand the impact categories included and the progress made towards more comprehensive LCA. Our search of publications between 2000 and 2016 identified 173 relevant peer-reviewed papers. Nearly all the publications (98%) included climate change as an impact category and almost one-third of the publications (28%) focused solely on that one category. Biodiversity, ionizing radiation, and particulate matter were the least common categories addressed. Cattle LCA, including dairy or beef, were the livestock species most frequently evaluated. Our analysis shows that while the number of multi-category livestock LCA (LCA with 4 or more impact categories) increased over time, LCA including 1–3 impact categories (which we define as “simplified LCA”) increased at a higher rate than multi-category LCA. Simplified LCA therefore remain the most prevalent in the literature. Publications that included multiple impact categories were better able to identify environmental impact tradeoffs among livestock production systems and management scenarios. To compare results across livestock LCA studies, it is necessary to increase the standardization of system boundaries, functional units, impact frameworks and mandatory inputs. The optional steps of normalization and weighting in the life cycle impact assessment can also help decision-makers prioritize which environmental impacts to address. More work that includes a greater number of impact categories in livestock LCA is sorely needed to more fully understand and to harmonize the communication of the environmental performance of livestock production systems. [ABSTRACT FROM AUTHOR]

• Environmental life cycle impacts are assessed for current and future heating. • Electric air source heat pumps are the lowest-impact option to decarbonise heating. • Boilers using H 2 from natural gas with carbon capture cannot achieve Net Zero. • Boilers using hydrogen from electrolysis have the highest impacts in 17 categories. • The proposed 2050 Net Zero heating mixes reduce GHG emissions by 84–94% per kWh. Heating and hot water within buildings account for almost a quarter of global energy consumption. Approximately 90% of this heat is derived directly from the combustion of fossil fuels, primarily natural gas, leading to the unabated emission of carbon dioxide. This paper assesses the environmental sustainability of a range of heating technologies and scenarios on a life cycle basis. The major technologies considered are natural gas boilers, air source heat pumps, hydrogen boilers and direct electric heaters. The scenarios use the UK as an example due to its status as a major economy with a legally-binding net-zero carbon target for 2050; they consider plausible future electricity and natural gas mixes, including the potential growth of domestic shale gas. The environmental impacts are estimated using ReCiPe 2016. Current gas boilers have a climate change impact of 220 g CO 2 eq./kWh of heat, which could fall to 64 g CO 2 eq./kWh for boilers fuelled by hydrogen derived from natural gas with carbon capture. Heat from electric air source heat pumps or hydrogen from electrolysis can achieve net zero with a decarbonised electricity mix, but electrolysis has the highest energy demand of all options which leads to the highest impacts across 17 of the 19 categories. Despite their high carbon emissions, gas boilers remain the lowest impact option across 12 categories as they avoid the impacts related to electricity generation, including metal depletion, toxicities and eutrophication. By 2050, the best performing scenario sees the climate change impact of the heating mix fall by 95%; this is achieved by prioritising electric air source heat pumps without hydrofluorocarbon refrigerants, alongside demand reduction. The results show that, if infrastructure and financial challenges can be overcome, there are several viable decarbonisation strategies for heating, with heat pumps offering the most environmentally sustainable option of those considered here. However, increased renewable electricity demand may worsen some environmental impacts compared to natural gas boilers. [ABSTRACT FROM AUTHOR]

The bioenergy sector is showing a recent development in Lebanon, a Mediterranean country, where the valorization of forestry and agricultural waste through briquetting consists one of the mostly applied and targeted applications. This study aims at analyzing the life cycle environmental impacts of biomass briquettes produced from olive pruning residues and used for heating purposes in traditional Lebanese stoves. The biomass briquettes are mainly introduced as a replacement for the light fossil fuels widespread used in similar stoves for the same purpose. Consequently, this paper also extends the literature-found comparison of the consumption phases between biomass briquettes and light fossil fuels to a comparative gate-to-gate LCA of these products. For the briquette itself, the results indicate that the "consumption" life cycle stage is the one that contributes to the most to all damage categories. Its contribution is 61%, 94%, 80% and 79% of the total contribution to "Human Health", "Ecosystem quality", "Climate change", and "Resources" damage categories respectively. When compared to light fossil fuels, biomass briquettes present overall better environmental results with exceptions for "Non-carcinogens" (6.28E-04 kg C 2 H 3 Cl eq), "Aquatic ecotoxicity" (1.01E-02 kg TEG water), "Terrestrial ecotoxicity" (5.04E-02 kg TEG soil), and "Land occupation" (9.37E-03 m2org.able) impact categories. This overall outcome is mainly linked to the fact that biomass briquettes are used as a replacement to traditionally adopted energy sources while reducing burning activities in the field. Moreover, sensitivity and uncertainty analyses are also conducted to verify the robustness of the results. [ABSTRACT FROM AUTHOR]