A multi-objective optimisation model for CCS chains, aiming to minimise costs and greenhouse gas emissions, considering various transport options is presented. The model builds upon previous work and ...covers the CCS chain elements after CO2 is captured, including conditioning, pipeline and batch-wise transportation, intermediate hub storage and injection at CO2 storage fields. A prospective Life Cycle Inventory is integrated to evaluate emissions from batch-wise transportation. The model is parameterised for accurate estimations based on site-specific characteristics and is implemented in two standalone CCS chains, that are analogues to the Northern Lights project with dominant ship transport and the Stella Maris concept with direct injection ship transport, also incorporating distinct emission profiles, intermediate storage hubs and injection sites. A third implementation combining both chain concepts is implemented. By increasing in a step-wise manner the weight of the emissions in the objective function, the model evaluates cost and emission trade-offs. The optimisation selects costlier wells to minimise emissions and shifts from batch-wise ships to cross-continent pipelines. Chain emissions decrease over time with CO2 supply increase. Shipping operation dominates emissions, followed by well construction and infrastructure construction. Across all the implementations, the GHG emission intensity of the chain, after CO2 is captured, ranged from 3.3 to 14.2 %, depending on the concept and transport option adopted and accounting for regional characteristics (i.e., the electricity supply mix per country).
Ramping up automotive lithium-ion battery (LIB) production volumes creates an imperative need for the establishment of end-of-life treatment chains for spent automotive traction battery packs. Life ...Cycle Assessment (LCA) is an essential tool in evaluating the environmental performance of such chains and options. This work synthesises publicly-available data to expand upon previously reported LCA studies for LIB recycling and holistically model end-of-life treatment chains for spent automotive traction battery packs with lithium nickel cobalt manganese oxide positive electrodes. The study provides an in-depth analysis of unit process contributions to the environmental benefits and burdens of battery recycling options and integrates these with the battery production impacts to estimate the net environmental benefit achieved by the introduction of recycling in the value chain. The attributional LCA model accounts for the whole recycling chain, from the point of end-of-life LIB collection to the provision of secondary materials for battery manufacturing. Pyrometallurgical processing of spent automotive traction battery cells is predicted to have a larger Global Warming Potential (GWP), due to its higher energy intensity, while hydrometallurgical processing is shown to be more environmentally beneficial, due to the additional recovery of lithium as hydroxide. The majority of the environmental benefits arise from the recovery of aluminium and copper fractions of battery packs, with important contributions also arising from the recovery of nickel and cobalt from the battery cells. Overall, the LCA model presented estimates a net benefit in 11 out of 13 environmental impact categories based on the ReCiPe characterisation method, as compared to battery production without recycling. An investigation of the effect of geographic specificity on the combined production and recycling indicates that it is as a key source of GWP impact variability and that the more climate burdening chains offer a significantly higher potential for GWP reductions through battery recycling. The sensitivity analysis carried out shows that impacts related to air quality are higher when recovering lower grade materials. This study provides a quantitative and replicable inventory model which highlights the significance of the environmental benefits achieved through the establishment of circular automotive battery value chains.
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•Life cycle assessment of leading Li-ion battery recycling options is investigated.•Hydrometallurgical processing is more beneficial due to the recovery of Li.•Most environmental benefits arise from recovered Al, Cu and Co fractions.•Recycling achieves reductions of more than 30% in 11 out of 13 impact categories.•Geographic specificity is a key source of GWP variability.
Advances in lithium-ion battery (LIB) technology, offering higher mass specific energies, volumetric energy densities, potential differences and energy efficiencies, are key enablers of the ...large-scale uptake of electric vehicles (EVs). Nickel-cobalt-manganese oxide (NCM) cathode formulations have emerged as the dominant choice in the battery industry. Further performance improvements are expected from the introduction of silicon-graphite composite anodes and nickel-rich cathodes alongside cost reductions achieved through upscaling the battery manufacturing. This work presents results of life cycle assessments concerning the environmental burdens associated with the production of novel electrode batteries and the impacts of the Chinese domination in lithium-ion battery manufacturing. The production of LIBs in China was shown to come at a high environmental cost of 40% higher Global Warming Potential (GWP) than earlier literature suggests. The novel batteries were shown to exhibit similar threats to humans and ecosystems as the commercialised ones, occurring mainly from the metals used in the battery cells; environmental impact reductions are shown to occur as a result of the increased nominal storage capacities of novel battery technologies. The replicable model presented provides the means to quantify the environmental impacts of production of LIBs including those with novel electrode chemistries and offers robust means of decision making that complement scientific and engineering developments targeting LIB performance improvements and cost reductions.
The production of LIBs in China was shown to come at a high environmental cost of 40% higher Global Warming Potential (GWP) than earlier literature suggests. The novel batteries were shown to exhibit similar threats to humans and ecosystems as the commercialised ones. Display omitted
•Chinese battery production comes at a higher environmental cost compared to preceding literature.•Novel batteries exhibit similar threats to humans and ecosystems as the commercialised ones.•Increased energy densities of novel battery technologies reduce environmental impacts.
The sustainability of food production systems is inherently linked with energy, water and food (EWF) resources directly and in-directly throughout their lifecycle. The understanding of the ...interdependencies between the three resource sectors in the context of food production can provide a measurable account for resource requirements, while meeting food security objectives. The energy, water and food Nexus tool developed by the authors has been designed to model the inter-dependency between energy, water and food resources, whilst conducting an environmental assessment of product systems. With emphasis on the inter-linkages between EWF resources, the tool quantifies material flows, natural resource and energy consumption at component unit process level. This work integrates greenhouse gas control and waste to power technologies within the energy, water and food Nexus tool and evaluates the environmental impact of a hypothetical food product system designed to deliver a perceived level of food self-sufficiency (40%) for the State of Qatar. Multiple system configurations, representative of different pathways for the delivery of consistent food products are evaluated, transforming a once linear product system into a circular design. The sub-systems added consist of a biomass integrated gasification combined cycle which recycles solid waste into useful forms of energy that can be re-used within the nexus. In addition, a carbon capture sub-system is integrated to capture and recycle CO2 from both the fossil fuel powered and the biomass integrated gasification combined cycle energy sub-systems. The integration of carbon capture with the biomass integrated gasification combined cycle transforms the carbon neutral biomass integrated gasification combined cycle process to a negative greenhouse gas emission technology known as bio-energy with carbon capture and storage. For the different scenarios and sub-system configurations considered, the global warming potential can be theoretically balanced (reduced by ∼98%) through the integration of photovoltaics, biomass integrated gasification combined cycle and carbon capture technologies. The peak global warming potential, i.e. a fully fossil fuel dependent system, is recorded at 1.73 × 109 kg CO2 eq./year whilst the lowest achievable global warming potential is 2.18 × 107 kg CO2 eq./year when utilising a combination of photovoltaics, carbon capture integrated with combined cycle gas turbine in addition to the integrated negative emission achieving system. The natural gas consumption is reduced by 7.8 × 107 kg/year in the best case configuration, achieving a credit. In the same scenario, the photovoltaics land footprint required is calculated to a maximum of 660 ha. The maximum theoretically achievable negative emission is 1.09 × 109 kg CO2/year.
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•An expanded energy, water and food nexus assessment tool is presented.•Multiple system configurations and technologies are evaluated.•A biomass integrated gasification combined cycle recycles waste to useful energy.•Integration of carbon capture technology induces negative emissions.•Negative emission technology results in a near carbon neutral food system in Qatar.
•Impact of battery thermal management on cost and carbon footprint is investigated.•Integration of capacity degradation into techno-economic and carbon footprint models.•Life cycle cost and carbon ...footprint savings of 27% and 25% via liquid cooling.•Optimised cell design reduces cost and carbon footprint by 40% and 35%.
Electric vehicles using lithium-ion batteries are currently the most promising technology to decarbonise the transport sector from fossil-fuels. It is thus imperative to reduce battery life cycle costs and greenhouse gas emissions to make this transition both economically and environmentally beneficial. In this study, it is shown that battery lifetime extension through effective thermal management significantly decreases the battery life cycle cost and carbon footprint. The battery lifetime simulated for each thermal management system is implemented in techno-economic and life cycle assessment models to calculate the life cycle costs and carbon footprint for the production and use phase of an electric vehicles. It is demonstrated that by optimising the battery thermal management system, the battery life cycle cost and carbon footprint can be reduced by 27% (from 0.22 $·km−1 for air cooling to 0.16 $·km−1 for surface cooling) and 25% (from 0.141 kg CO2 eq·km−1 to 0.104 kg CO2 eq·km−1), respectively. Moreover, the importance of cell design for cost and environmental impact are revealed and an improved cell design is proposed, which reduces the carbon footprint and life cycle cost by 35% to 0.0913 kg CO2 eq·km−1 and 40% to 0.133$·km−1, respectively, compared with conventional cell designs combined with air cooling systems.
Although significant progress has been made in understanding how environmental factors modify the speciation, bioavailability and toxicity of metals such as copper in aquatic environments, the ...current methods used to establish water quality standards do not necessarily consider the different geological and geochemical characteristics of a given site and the factors that affect copper fate, bioavailability potential and toxicity. In addition, the temporal variation in the concentration and bioavailable metal fraction is also important in freshwater systems. The work presented in this paper illustrates the temporal and seasonal variability of a range of water quality parameters, and Cu speciation, bioavailability and toxicity at four freshwaters sites in the UK. Rivers Coquet, Cree, Lower Clyde and Eden (Kent) were selected to cover a broad range of different geochemical environments and site characteristics. The monitoring data used covered a period of around six years at almost monthly intervals.
Chemical equilibrium modelling was used to study temporal variations in Cu speciation and was combined with acute toxicity modelling to assess Cu bioavailability for two aquatic species, Daphnia magna and Daphnia pulex. The estimated copper bioavailability, toxicity levels and the corresponding ecosystem risks were analysed in relation to key water quality parameters (alkalinity, pH and DOC). Although copper concentrations did not vary much during the sampling period or between the seasons at the different sites; copper bioavailability varied markedly. In addition, through the chronic-Cu BLM-based on the voluntary risk assessment approach, the potential environmental risk in terms of the chronic toxicity was assessed. A much higher likelihood of toxicity effects was found during the cold period at all sites. It is suggested that besides the metal (copper) concentration in the surface water environment, the variability and seasonality of other important water quality parameters should be considered in setting appropriately protective environmental quality standards for metals.
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•Temporal/seasonal variations of water quality parameters may influence EQS compliance.•Sensitive site or catchment specific EQS is important in assessing aquatic metal toxicity.•EQS compliance evaluation for sensitive sites requires more intense sampling.
The urgency of climate change, while the world economy is projected to depend on fossil fuels for some time, requires substantial reduction of greenhouse gas emissions in the oil and gas industry. ...This study proposes a methodology for the decarbonisation of offshore natural gas production networks through progressive electrification, either by connecting offshore platforms with nearby renewable energy sources, e.g. offshore wind farms, or by sharing resources so as to improve their energy generation efficiency. In this context, a novel multi-objective mixed-integer linear programming model is proposed to simultaneously minimise greenhouse gas emissions and associated costs from a determined offshore platform network, considering technical constraints, such as maintaining the energy balance of the network, ensuring that cables are installed to enable energy flows, and respecting the maximum generation capacities and minimum operating loads of turbines. For demonstration purposes, the proposed methodology was applied to a UK Southern North Sea network and optimised using the augmented ε-constraint method. The Pareto front approximation obtained suggests that the studied network’s cumulative greenhouse gas emissions can be reduced by 25% over the next 10 years at an average cost of US$370.9 per tonne CO2e. This study also explores the impact that uncertainties and postponing investment decisions may have in the set context.
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•Offshore natural gas production GHG emissions can be reduced via electrification.•Energy generation options were analysed using a multi-objective optimisation model.•Sharing power production reduces GHG emissions in mature offshore fields in the UK.•GHG emissions reduction (25%) is achieved at average cost of US$370.9/tonneCO2e.•Integration with offshore wind farms provided the greatest benefits in the optima.
The TOPS project takes a radical and holistic approach to coupled UCG-CCS, and thus the site selection criteria for the coupled processes, considering both geological, reservoir and process ...engineering aspects and different end-uses of the produced synthetic gas in order to optimise the whole value chain. In particular, the experimental research carried out utilises a newly constructed high pressure gasification reactor investigating several prospective options of UCG technology implementations. Integrated research addresses field based technology knowledge gaps, such as cavity progression and geomechanics, potential groundwater contamination and subsidence impacts, together with research into process engineering solutions in order to assess the role/impact of site specific factors and selected reagents on the operability of given CO2 emission mitigation options. Ultimately, research aims to minimise the need for on-site CO2 storage capacity as well as maximising the economic yield of UCG through value added end products.
Despite the recognised risks of human exposure to mercury (Hg), the drivers of gaseous elemental mercury (GEM) emissions from the soil remain understudied. In this study, we aimed to identify the ...environmental parameters that affect the GEM flux from soil and derive the correlations between environmental parameters and GEM flux. Principal component analysis (PCA), factor analysis (FA), and structural equation modelling (SEM) were performed on samples from forest and non-forest sites. The associated results revealed the impact of each environmental parameter on GEM flux, either due to the interaction between the parameters or as a coherent set of parameters. An introductory correlation matrix examining the relationship between two components showed a negative correlation between GEM flux and atmospheric pressure at the two sites, as well as strong correlations between atmospheric pressure and soil temperature. In cases of non-forest open sites with no trees, the PCA and FA results were consistent, indicating that atmospheric pressure, solar irradiance, and soil moisture—defined as primary causality—are largely independent drivers of GEM flux. In contrast, the PCA and FA results for the forest areas with high humidity, tree coverage, and shade were inconsistent, confirming the hypothesis that primary causality affects GEM flux rather than consequent parameters driven by primary causality, such as air and soil temperature and atmospheric humidity. The SEM results provided further evidence for primary and consequent causality as crucial drivers of the GEM flux. This study demonstrates the importance of key primary parameters, such as atmospheric pressure, solar irradiance, and soil moisture content, that can be used to predict mercury release from soils, as well as the importance of consequent parameters, such as air and soil temperature and atmospheric humidity. Monitoring the magnitude of these environmental parameters alone may facilitate the estimation of mercury release from soils and be useful for detailed modelling of soil–air Hg exchange.
•Atmospheric pressure, solar irradiance, and soil moisture primary drives Hg release.•Parameter interactions vary between sites and significantly impact Hg release.•The primary and consequent parameter effects differ in forest and non-forest sites.•Hg release can be estimated when primary meteorological causality is known.
•The lower energy content lignite produced a syngas with comparatively better energy efficiency.•Life cycle carbon footprint of UCG-IGCC plants depends more on the process driven syngas composition ...rather than the in-situ methane content.•Life cycle carbon footprint of conventional above ground coal fired power generation depends on the in-situ CH4 content and CH4 emissions during mining.•Bituminous coal UCG-IGCC plants have a greater life cycle carbon footprint than that of lignite UCG-IGCC plants.•UCG methanol production and CCS releases more life cycle CO2-eq emissions than UCG ammonia.
Underground coal gasification (UCG) has the potential to provide a source of energy or chemical feedstock derived from coal seams, where traditional mining methods are not suitable or are uneconomical. This paper presents the life cycle inventory models developed for the UCG processes and three alternative syngas utilisation options with and without CO2 capture and storage. The paper compares the life cycle carbon footprint of two different conventional above ground coal fired power generation options with UCG Integrated Gasification Combined Cycle power generation with/without CCS for two different lignites and one bituminous coal. One of the lignites is then used to compare the life cycle performance of different syngas utilisation options: power generation, ammonia production with power generation, and methanol production with power generation. It was found that the life cycle carbon footprint of conventional above ground coal fired power generation is very much dependent on the in-situ methane content of the coal used, and methane emissions experienced during mining and accompanying upstream processes, whereas the same for UCG-IGCC power depends more on the process dependent syngas composition. UCG methanol production with associated power and CCS is shown to release more life cycle CO2-eq emissions per tonne of lignite consumed than that of UCG ammonia production with associated power and CCS and UCG CCGT power generation with CCS. Furthermore, when chemicals production from UCG is considered as the main objective, the most substantial improvements in comparison to conventional methods are associated with UCG ammonia process per tonne of chemical produced.
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