Life cycle assessment of marine power systems onboard roll-on/roll-off cargo ships : framework and case studies

PhD ThesisA study into the environmental impact of marine power systems was performed in proximity with the defined research objectives: (i) present an overview on Annex VI The International Convention for the Prevention of Pollution from Ships, cargo ships, marine power systems and technologies; (ii) review life cycle assessment (LCA) methodology development; (iii) develop an LCA framework for marine power systems; (iv) carry out case studies to determine environmental impact, significant components and critical processes; (v) apply scenario analysis to investigate the sensitivity of the results to selected parameters; and (vi) compare power systems under study to verify their environmental benefits. Built upon literature and the proposed LCA framework, LCA case studies on conventional, retrofit and new-build power systems were performed using a bottom-up integrated system approach, where data were gathered and LCA models were created for individual technologies using GaBi software. Life cycle impact assessment was performed using CML2001, International Reference Life Cycle Data System (ILCD) and Eco-Indicator99 to estimate the environmental impact of the systems. It was found that disposing metal scrap of significant components was the principal cause of ecotoxicity potential, which was the impact category that showed the top two highest indicator results; and operating diesel engines and auxiliary generators or diesel gensets was mainly accounted for other impact categories. When compared with the conventional system, both retrofit and new-build systems consumed less fuels and released less emissions during operation but involved more materials and energy during other life cycle phases, leading to a decline in most impact categories to the detriment of a few burdens. The life cycle of marine power systems must be planned, managed and monitored appropriately for reduced environmental implications. Further research should address limitations presented in this study and explore other factors that might affect the environmental burdens of marine power systems.Research presented in this thesis was delivered for a European Commission funded FP7 project ‘INOvative Energy MANagement System for Cargo SHIP’ (INOMANS²HIP, grant agreement no: 266082)

Techno-economic assessment of offshore wind-to-hydrogen scenarios: A UK case study

The installed capacity, electricity generation from wind, and the curtailment of wind power in the UK between 2011 and 2021 showed that penetration levels of wind energy and the amount of energy that is curtailed in future would continue to rise whereas the curtailed energy could be utilised to produce green hydrogen. In this study, data were collected, technologies were chosen, systems were designed, and simulation models were developed to determine technical requirements and levelised costs of hydrogen produced and transported through different pathways. The analysis of capital and operating costs of the main components used for onshore and offshore green hydrogen production using offshore wind, including alternative strategies for hydrogen storage and transport and hydrogen carriers, showed that a significant reduction in cost could be achieved by 2030, enabling the production of green hydrogen from offshore wind at a competitive cost compared to grey and blue hydrogen. Among all scenarios investigated in this study, compressed hydrogen produced offshore is the most cost-effective scenario for projects starting in 2025, although the economic feasibility of this scenario is strongly affected by the storage period and the distance to the shore of the offshore wind farm. Alternative scenarios for hydrogen storage and transport, such as liquefied hydrogen and methylcyclohexane, could become more cost-effective for projects starting in 2050, when the levelised cost of hydrogen could reach values of about £2 per kilogram of hydrogen or lower

A techno-economic investigation of conventional and innovative desiccant solutions based on moisture sorption analysis

Liquid desiccant technology is an energy-efficient substitute for technologies that are conventionally applied for temperature and humidity control; however, innovative desiccant solutions have not been extensively explored in terms of their performance and feasibility. This work aimed to investigate desiccant solutions with moisture sorption analysis technically and economically. Various conditions of temperature and humidity were tested in a climatic chamber and the moisture absorption and desorption capacity, thermo-chemical energy storage capacity, and cost of conventional and innovative desiccant solutions were assessed by experiment. Calcium chloride showed the highest moisture desorption capacity (0.3113 gH2O/gsol in the climatic chamber at 50 °C and 25% RH) and the lowest cost, despite its low moisture absorption capacity. Ionic liquids show high moisture absorption capacity (as high as 0.429 gH2O/gsol in the climatic chamber at 25 °C and 90% RH) and could be used as additives (in which a maximum increase of 84.1% was observed for moisture absorption capacity due to the addition of ionic liquids), and thus, they are promising substitutes for conventional desiccant solutions. As solutions for better performance under various conditions were identified, the study will advance liquid desiccant technology

A techno-economic evaluation of low-grade excess heat recovery and liquid desiccant-based temperature and humidity control in automotive paint shops

The paint shop is the most energy-intensive process in an automotive manufacturing plant, with air management systems that supply air to paint booths consuming the most energy. These systems are crucial for temperature and humidity control, in which they ensure the quality of the final product by preventing paint defects and thus avoid the additional cost of reworking. This is especially true for water-based paints, in which evaporation and film formation processes are influenced by the temperature and humidity of the surrounding air. This study aims to investigate the incorporation of liquid desiccant technology into a conventional air management system for paint shops operating in different climates, which presents the novelty of the study. The technology is promising because it can regulate humidity, act as a dehumidifier or humidifier depending on the demand and stores energy in a thermo-chemical form. In addition, waste heat sources available in the paint shop can be used for the regeneration of the liquid desiccant solution. The techno-economic evaluation of this novel process indicates that the proposed system can control the temperature and humidity of the supply air within the range required for optimal painting and achieve significant energy savings in both cold and hot/humid climates, with a reduction of 44.4% and 33.6% of the energy cost compared to the conventional operation and a payback period of 6.15 and 5.74 years respectively, using calcium chloride as the desiccant solution. The sensitivity analysis investigates the effect of the energy and carbon price on the performance of the system. It is concluded that the integration of liquid desiccant technology into conventional air management systems for paint booths has a huge potential to increase the energy-efficiency of automotive painting

Techno-economic and environmental analyses of hybrid renewable energy systems for a remote location employing machine learning models

This article offers a detailed investigation into the technical, economic along with environmental performance of four configurations of hybrid renewable energy systems (HRESs), aiming at supplying renewable electricity to a remote location, Henry Island in India. The study explores combinations involving photovoltaic (PV) panels, wind turbines, biogas generators, batteries, and converters, while evaluating their economic, technical, and environmental performance. The economic analysis yield that among all the systems examined, the PV, wind turbine, biogas generator, battery, and converter integrated configuration stands out with highly favourable results, showcasing the minimal value of levelized cost of electricity (LCOE) at $0.4224 per kWh and the lowest net present cost (NPC) at$6.41 million. However, technical analysis yield that the configuration comprising wind turbines, PV panels, converters, and battery yields a maximum excess electricity output of 2,838,968 kWh/yr. Additionally, machine learning techniques are employed to analyse economic and environmental performance data. The study shows Bilayered Neural Network model achieves exceptional accuracy in predicting LCOE, while the Medium Neural Network model proves to be the most accurate in predicting environmental performance. These findings provide valuable perception into the design and optimisation of HRES systems for off-grid applications in remote regions, taking into account their technical, economic, and environmental aspects

Techno-economic analysis of the thermal energy saving options for high-voltage direct current interconnectors

High-voltage direct current interconnection stations are increasingly used for long-distance electricity transport worldwide, due to efficiency and economic reasons. The identification and evaluation of cost-effective waste heat sources appropriate for recovery and reutilisation represent an opportunity that can improve the efficiency of high-voltage direct current stations, resulting in significant savings in energy consumption and reduction of the carbon footprint. The paper is the first to investigate the technological and economic feasibility of heat recovery at a major interconnector power station. Once identified the potential recoverable heat sources and evaluated the latest advancements in thermal energy recovery technology, a technological and economic analysis of two potential heat recovery strategies has been performed. While the heat-to-electricity technology was proved to be technologically but not economically feasible, the realisation of a combined liquid desiccant and evaporative cooling heat recovery strategy was proved to present the best economic performance with a payback period of about 5 years and a levelised cost of saved energy of 0.155 €/kWh, depending on the heat recovery and size of the system. Additional economic savings can be obtained for high-voltage direct current stations located in hot and humid climates, where the moisture removal ability of liquid desiccant technology could be particularly advantageous

Research and innovation identified to decarbonise the maritime sector

The maritime sector requires technically, environmentally, socially, and economically informed pathways to decarbonise and eliminate all emissions harmful to the environment and health. This is extremely challenging and complex, and a wide range of technologies and solutions are currently being explored. However, it is important to assess the state-of-the-art and identify further research and innovation required to accelerate decarbonisation. The UK National Clean Maritime Research Hub have identified key priority areas to drive this process, with particular focus on marine fuels, power and propulsion, vessel efficiency, port operations and infrastructure, digitalisation, finance, regulation, and policy.This article was delivered by the UK National Clean Maritime Research Hub established on the 1st September 2023 supported by the UK Department for Transport (DfT) as part of the UK Shipping Office for Reducing Emissions (UK SHORE) Programme and Engineering and Physical Sciences Research Council (EPSRC) [grant number EP/Y024605/1]

Industrial cluster energy systems integration and management tool

Critical for achieving the United Kingdom's net-zero targets, decarbonising industrial clusters would require robust tools to assess the feasibility of decarbonisation technologies and investment solutions. This paper presents an integrated energy system planning tool for decarbonising industrial clusters. The adoption of the transfer functions method enables the development of individual component models for technologies, networks, and loads, facilitating the control and simulation of complex dynamics in multi-energy system operation, as demonstrated in a case study investigating heat and power demands of a dynamic hybrid cluster, with evaluation of decarbonisation implications including heat electrification, renewables, and fuel switching in both grid-connected and island modes to establish potential pathways for decarbonisation. With the implementation of these decarbonisation measures in the case study cluster, primary energy demand, costs, emissions, and energy losses were reduced by 42%, 71%, 53%, and 72% in grid mode and by 40%, 70%, 53%, and 63% in island mode, and higher losses in island mode is due to excess heat production by electric boilers intended to consume all available power. While outcomes might differ among various clusters due to their specific features, the study cluster, characterised by substantial heat demand compared to electricity and significant electricity exports, achieves significant emission reduction via heat electrification compared to other individual decarbonisation technology. Moreover, this tool will be instrumental in helping industrial clusters formulate comprehensive decarbonisation roadmaps based on informed decisions

Research and innovation identified to decarbonise the maritime sector

The maritime sector requires technically, environmentally, socially, and economically informed pathways to decarbonise and eliminate all emissions harmful to the environment and health. This is extremely challenging and complex, and a wide range of technologies and solutions are currently being explored. However, it is important to assess the state-of-the-art and identify further research and innovation required to accelerate decarbonisation. The UK National Clean Maritime Research Hub have identified key priority areas to drive this process, with particular focus on marine fuels, power and propulsion, vessel efficiency, port operations and infrastructure, digitalisation, finance, regulation, and policy

Investigating the implications of a new-build hybrid power system for Roll-on/Roll-off cargo ships from a sustainability perspective – A life cycle assessment case study

Marine transport has been essential for international trade. Concern for its environmental impact was growing among regulators, classification societies, ship operators, ship owners, and other stakeholders. By applying life cycle assessment, this article aimed to assess the impact of a new-build hybrid system (i.e. an electric power system which incorporated lithium ion batteries, photovoltaic systems and cold-ironing) designed for Roll-on/Roll-off cargo ships. The study was carried out based on a bottom-up integrated system approach using the optimised operational profile and background information for manufacturing processes, mass breakdown and end of life management plans. Resources such as metallic and non-metallic materials and energy required for manufacture, operation, maintenance, dismantling and scrap handling were estimated. During operation, 1.76 × 108 kg of marine diesel oil was burned, releasing carbon monoxide, carbon dioxide, particulate matter, hydrocarbons, nitrogen oxides and sulphur dioxide which ranged 5–8 orders of magnitude. The operation of diesel gensets was the primary cause of impact categories that were relevant to particulate matter or respiratory inorganic health issues, photochemical ozone creation, eutrophication, acidification, global warming and human toxicity. Disposing metallic scrap was accountable for the most significant impact category, ecotoxicity potential. The environmental benefits of the hybrid power system in most impact categories were verified in comparison with a conventional power system onboard cargo ships. The estimated results for individual impact categories were verified using scenario analysis. The study concluded that the life cycle of a new-build hybrid power system would result in significant impact on the environment, human beings and natural reserves, and therefore proper management of such a system was imperative