S.C.L. Koh’s research while affiliated with The University of Sheffield and other places

Due to high toxicity, thermal instability at high temperature, low availability, and the high cost of raw metallic alloys such as Bi2Te3 for thermoelectric (TE) applications, there has been a drive to develop earth-abundant and eco-benign TE materials suitable for high-temperature applications. Oxide-based TEs have lately been touted to satisfy these criteria, but a lifecycle assessment (LCA) and energy payback period (EPBP) assessment of both classes of materials have not been conducted. This paper presents a comparative LCA of two laboratory-based TE modules namely, non-oxide n-type selenium-doped Bi2Te3 and p-type antimony-doped Bi2Te3 (Module A) versus oxide-based n-type lanthanum-doped SrTiO3 and p-type layered Ca3Co4O9 (Module B). Electrical energy consumption (EEC) during fabrication constitutes the largest impact for both modules, even under a decarbonised grid scenario, although Module B has an overall lower EEC. Nonetheless, for Module A, the use of tellurium and antimony exhibited noticeable environmental toxicity impacts, but smaller compared to EEC. The rare earth elements contained in the n-type component of Module B, showed negligible environmental toxicity impact, but those from its p-type component is noticeably high due to the presence of cobalt oxide. Computations of performance characteristics based on the material configurations of both modules showed that Module A yielded a higher power output compared to Module B, and as the power output increases, the EPBP becomes almost identical for both modules, underscoring its integral role to EEC offsetting. Key challenges, therefore, once EEC is diminished for large-scale applications are raw materials availability and cost, alongside performance.

Energy exchange technologies will play an important role in the transition towards localised, sustainable energy supply. Hybrid energy storage systems, using different energy storage technologies, are currently under investigation to improve their technical performance and environmental sustainability. However, there is currently no exploration of the environmental benefits and economic feasibility of hybrid energy storage systems combining 1st and 2nd life batteries and battery electric vehicles. To determine the environmental and economic impacts of this type of hybrid energy storage system, this research employs a three-tier circularity assessment incorporating Life Cycle Assessment, Techno Economic Analysis and an Eco-Efficiency Index, from cradle-to-grave, of 43 techno-hybridisations of four 1st and 2nd life battery technologies; Lithium Titanate, Lead-acid, Lithium Iron Phosphate and Sodium-ion, with battery electric vehicles. The results of the life cycle assessment and techno-economic analysis show that a hybrid energy storage system configuration containing a low proportion of 1st life Lithium Titanate and battery electric vehicle battery technologies with a high proportion of 2nd life Lithium Titanate batteries minimises the environmental and economic impacts and provides a high eco-efficiency. The results of the eco-efficiency index show that a hybrid energy storage system configuration containing equal proportions of 1st and 2nd life Lithium Titanate and BEV battery technologies is the most eco-efficient. This research highlights the environmental and economic benefits of the use of Lithium Titanate battery technologies within novel hybrid energy storage systems.

The World Health Organization declared COVID-19 a global pandemic on the 11th of March 2020, but the world is still reeling from its aftermath. Originating from China, cases quickly spread across the globe, prompting the implementation of stringent measures by world governments in efforts to isolate cases and limit the transmission rate of the virus. These measures have however shattered the core sustaining pillars of the modern world economies as global trade and cooperation succumbed to nationalist focus and competition for scarce supplies. Against this backdrop, this paper presents a critical review of the catalogue of negative and positive impacts of the pandemic and proffers perspectives on how it can be leveraged to steer towards a better, more resilient low-carbon economy. The paper diagnosed the danger of relying on pandemic-driven benefits to achieving sustainable development goals and emphasizes a need for a decisive, fundamental structural change to the dynamics of how we live. It argues for a rethink of the present global economic growth model, shaped by a linear economy system and sustained by profiteering and energy-gulping manufacturing processes, in favour of a more sustainable model recalibrated on circular economy (CE) framework. Building on evidence in support of CE as a vehicle for balancing the complex equation of accomplishing profit with minimal environmental harms, the paper outlines concrete sector-specific recommendations on CE-related solutions as a catalyst for the global economic growth and development in a resilient post-COVID-19 world.

This study provides new insight into current and emerging supply chain approaches and related power relations deriving from public procurement processes within Local Authorities (LAs). Drawing on a mixed-method empirical research (involving data from LAs across the Yorkshire and Humber region of the United Kingdom) this research examines stakeholder pressures, paying particular attention to principal-agent and dependency relationships between public sector and private companies in public procurement projects. Resource Dependency Theory is used as the theoretical framework to support the study. The paper presents and critically evaluates across a set of dimensions, four models of supply chain archetypes deriving from the implementation public procurement projects. These archetypes identify key stakeholders and determine power relations between main contractors, sub-contractors, government agencies and LAs for the delivery of public sector projects. The research carried out in this paper can inform practice, policy and research in aiding public organisations such as LAs in the design of projects before the procurement stage. Also, the research provides useful insight on how the procurement process can serve as a mechanism for LAs to manage activities of agents in order to achieve a range of objectives.

The rising cost of energy and concerns about the environmental impact of manufacturing processes have necessitated the need for more efficient and sustainable manufacturing. The ceramic industry is an energy intensive industrial sector and consequently the potential to improve energy efficiency is huge, particularly through the introduction of modern sintering technologies. Although several energy efficient sintering processes have been developed, there is no comprehensive techno-economic analysis which compares and contrasts these techniques. This paper presents a critical review and analysis of a number of sintering techniques and compares them with the recently developed cold sintering process (CSP), including mode of operation, sintering mechanism, typical heating rates, duration of sintering, energy consumption profile and energy saving potential, limitations, key challenges for further development and current research efforts. By using a figure of merit, pounds per tonne of CO2 saved (£/tCO2-eq), which links initial capital investment with energy savings, within a framework derived from ranking principles such as marginal abatement cost curves and Pareto optimisation, we have demonstrated that under the scenarios considered for 3 separate functional oxides ZnO, PZT and BaTiO3, CSP is the most economically attractive sintering option, indicating lower capital costs and best return on investment as well as considerable energy and emission savings. Although the current work establishes the viability of CSP as a competitive and sustainable alternative to other sintering techniques, the transition from laboratory to industry of CSP will require hugely different facilities and instrumentation as well as relevant property/performance validation to realise its full potential.

The prohibition of lead in many electronic components and devices due to its toxicity has reinvigorated the race to develop substitutes for lead zirconate titanate (PZT) based mainly on the potassium sodium niobate (KNN) and sodium bismuth titanate (NBT). However, before successful transition from laboratory to market, critical environmental assessment of all aspects of their fabrication and development must be carried out in comparison with PZT. Given the recent findings that KNN is not intrinsically ‘greener' than PZT, there is a tendency to see NBT as the solution to achieving environmentally lead-free piezoelectrics competitive with PZT. The lower energy consumed by NBT during synthesis results in a lower overall environmental profile compared to both PZT and KNN. However, bismuth and its oxide are mainly the by-product of lead smelting and comparison between NBT and PZT indicates that the environmental profile of bismuth oxide surpasses that of lead oxide across several key indicators, especially climate change, due to additional processing and refining steps which pose extra challenges in metallurgical recovery. Furthermore, bismuth compares unfavourably with lead due to its higher energy cost of recycling. The fact that roughly 90–95% of bismuth is derived as a by-product of lead smelting also constitutes a major concern for future upscaling. As such, NBT and KNN do not offer absolute competitive edge from an environmental perspective in comparison to PZT. The findings in this work have global practical implications for future Restriction of Hazardous Substances (RoHS) legislation for piezoelectric materials and demonstrate the need for a holistic approach to the development of sustainable functional materials.

Solar cells are considered as one of the prominent sources of renewable energy suitable for large-scale adoption in a carbon-constrained world and can contribute to reduced reliance on energy imports, whilst improving the security of energy supply. A new arrival in the family of solar cells technologies is the organic-inorganic halide perovskite. The major thrust for endorsing these new solar cells pertains to their potential as an economically and environmentally viable option to traditional silicon-based technology. To verify this assertion, this paper presents a critical review of some existing photovoltaic (PV) technologies in comparison with perovskite-structured solar cells (PSCs), including material and performance parameters, production processes and manufacturing complexity, economics, key technological challenges for further developments and current research efforts. At present, there is limited environmental assessment of PSCs and consequently, a methodologically robust and environmentally expansive lifecycle supply chain assessment of two types of PSC modules A and B is also undertaken within the context of other PV technologies, to assess their potential for environmentally friendly innovation in the energy sector. Module A is based on MAPbX3 perovskite structure while module B is based on CsFAPbX3 with improved stability, reproducibility and high performance efficiency. The main outcomes, presented along with sensitivity analysis, show that PSCs offer more environmentally friendly and sustainable option, with the least energy payback period, as compared to other PV technologies. The review and analysis presented provide valuable insight and guidance in identifying pathways and windows of opportunity for future PV designs towards cleaner and sustainable energy production.

Purpose Although studies have demonstrated the importance of supply chain integration (SCI) strategies in improving firm performance, very little is understood about how the organizational structure (OS) of focal firms affects the successful implementation of SCI initiatives across supply chains (SCs). Taking into consideration the importance of the oil and gas (O&G) industry, as well as the impact of uncertainties on OS and strategy choices, it is important to understand how OS and SCI affect the operational performance of O&G SCs. The paper aims to discuss this issue. Design/methodology/approach Taking a contingency approach and using a global sample of 181 O&G firms, this study examines the mediating role of internal, customer, and supplier integration on the relationship between three main dimensions of OS – the degree of centralization, formalization, and hierarchical relationships and operational performance, using structural equation modeling. Findings Findings reveal that OS dimensions negatively impact operational performance. Further testing for the mediation found that by increasing SCI, O&G SCs can mitigate the negative effect of high centralization, formalization, and hierarchical relationship on operational performance. Research limitations/implications Classifying OS into “structuring” and “structural,” this research provides evidence on which of the two has a stronger negative impact on operational performance. This is significant since it may be difficult for O&G companies to restructure and reform their OS. Originality/value This study examines the impact of OS and SCI on improving the operational performance of the O&G SCs. Theoretical and practical contributions to the field of operations management and organizational studies are also discussed.

For over twenty years, researchers and practitioners have been developing and implementing different methods for combining environmental and economic analysis of products, technologies and systems. However, there is little evidence that one generally accepted method exists. Due to the diversity of different methods there has been, surprisingly, no detailed investigation of the different methods, the interrelationship between methods, and more importantly how they can advance integrated methods for Life Cycle Assessment (LCA) and Life Cycle Costing (LCC). In this paper, a novel hybridised framework is presented combining six integrated methods which were identified after an extensive and critical literature review for environmental life cycle assessment and life cycle costing. The hybridised framework is the first of its kind and aims to provide decision-makers a comprehensive method to navigate environmental and economic analysis. The key features are: (1) integrated framework capable of carrying out six types of LCA and LCC integration, (2) inclusion of multiple perspectives for decision-making, (3) decision making process to select different methods for system analysis and system integration, (4) procedures for Conventional Life Cycle Costing (CLCC) and Environmental Life Cycle Costing (ELCC), (5) total costs including external ‘eco-costs' of environmental LCA impacts, (6) hybrid LCA combining benefits of both process and Economic-Input-Output (EIO)-LCA, (7) system optimisation by Multi-Objective Linear Programming (MOLP), (8) hybrid MCDA method combining the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) and Analytical Hierarchy Process (AHP), (9) Eco-efficiency (EE) index performance and alternative evaluation, (10) a range of graphical tools to interpret integrated LCA and LCC analysis, and (11) management of environmental and economic analysis by continuous improvement. Overall, the hybridised framework accommodates a wide array of different decision-making scenarios to analyse, improve and manage the environmental sustainability and economic prosperity of products, technology and systems.