Approaches to shipboard power generation systems design and management. Probabilistic approach to load prediction and system optimal design, sizing and management

This doctoral thesis presents new ideas and formulations on shipboard power system sizing and management. The main motivation behind this work is to fill, at least in part, the current technological and mythological gap between land and marine applications, concerning the sizing and management of power systems. This gap is the result of several changes regarding both the electric and marine applications. Two of these are, for example, the recent increase of electric power installed on board modern vessels and recent development of technologies for land microgrids. In this context, it should be noted that, also the modern ships are comparable to land microgrids, where the generation and loads are close in space and the on board power system may work either islanded or connected to the land grid. Nowadays, microgrids are a hot topic in electric engineering, with a constant development of novel approaches for both their sizing and management. On the other hand, considering the increase in the power installed on board ships, the traditional methods developed in the last century to size and manage these systems have shown increasing limitations and inaccuracies. This results in oversized power generation systems, low performances and high level of air and sea pollution due to ships activities. To overcome these problems and criticalities, this work presents a probabilistic approach to load prediction, which may increase the flexibility of the power system design and allow a significant reduction in the total power installed. Moreover, the traditional method to size the diesel generators, based on satisfying the maximum load, it is revised with the formulation of an optimal problem, which can consider as input either the results of the traditional method to load prediction or those obtained applying the probabilistic one. Finally, due to the recent introduction in land microgrids of energy storage system, which may cover the power fluctuations due to renewable resources, allow a better management of energy and increase the quality of service, an optimum method is developed and described in order to select, size and manage these systems on board ships

Ship Electrical Load Analysis and Power Generation Optimisation to Reduce Operational Costs

Nowadays the amount of electrical power generated on-board ships is drastically increased, especially for the All Electric Ships (AES) where all the energy needed is supplied by the electrical power system. In this context, the traditional methods to calculate the power demand and select the size of the generation system have become inadequate, since they are based on very dated assumptions. Aim of this paper is to present an optimum problem in order to correctly and efficiently size the generation system. The power demanded will be calculated using the traditional approach based on Load Factors. The optimum problem will be solved using the Genetic Algorithms, and provide the optimal size, load factors and unit commitment for each generator in each ship operative scenario

DECISION SUPPORT SYSTEM FOR POWER GENERATION MANAGEMENT FOR AN 110000+ GRT CRUISE SHIP

The aim of this work is to provide a methodology for the power generation optimization on large cruise ships in order to improve their operating efficiency, fuel saving and, consequently, to reduce exhaust gas emissions. The electrical load analysis is compared to the machinery reports of actual data in order to investigate if the estimated required power is appropriately close to the real power demand. Relevance is given to the average load of the diesel-generators, which expresses an indication of how the generators work. The model of the ship electric distribution system represents one of the main objectives of this work along with the power system simulations. These were developed through the definition of load profiles, both by the onboard recordings and by machinery reports data. Therefore, the same cruise profile is analyzed under different scenarios, the real and the optimized one, in order to highlight the critical state of the system and any possible margin for improvement

Optimal Sizing of Energy Storage Systems for Shipboard Applications

The recent worldwide effort on the environmental issue has led to new regulations on greenhouse gases emissions (GHG), both for land and marine applications. Nowadays, the extensive electrification of transportation systems is a promising choice for this purpose. In this perspective, algorithms for the optimum sizing and management of energy storage systems (ESSs) integrated into already operating shipboard power sys- tems are proposed in this work. The main aim of this method is reducing the power generation system fuel oil consumption, GHG emissions and management costs. This is applied to two case studies (i.e. a ferry and a platform supply vessel), of which load power profiles are available from the on-board integrated automation system (IAS). The results yielded show remarkable savings close to 6% and 32% along the whole ship's life horizon for the ferry and the platform supply vessel, respectively. These results prove that an optimal sizing combined with an optimum management of ESSs may significantly reduce the operative costs of shipboard power systems.acceptedVersion© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works

Dynamic Modeling of a Supply Vessel Power System for DP3 Protection System

The work is focused on modeling and simulation of a supply vessel from a static and dynamic perspective in an integrated way. Modern marine vessels with electric propulsion are becoming more and more complex systems. Therefore, there is a strong necessity to develop models capable to integrate different subsystems in order to evaluate the overall performance under faults conditions, harsh weather and other critical situations. In particular, the focus of the work is to highlight the need to implement zonal protection scheme to respect DP3 (Dynamic Position 3) constraints in case of severe busbar faults, operating the system with the main tie breaker closed. The model developed is characterized with a complete representation of a Platform Supply Vessel (PSV). The model represents also the full protection system (static and dynamic) in accordance to fine-tuning conducted on the real system. In this work, the innovative contribution is the investigation of the shortterm dynamics after a busbar faults with a detailed electric model of the full network taking into account zonal power system protections and load shedding actions. The work is also focused on representing the electromechanical model of the propulsion power converters

Innovative Energy Systems: Motivations, Challenges and Possible Solutions in the Cruise Ship Arena

The worldwide effort on the environmental issue in the maritime field has led to always more stringent regulations on greenhouse gas emission (GHG). In this perspective, the International Maritime Organization has developed regulations intended to increase the ship\u2019s efficiency and reduce GHG emissions both in design phase, through the introduction of an Energy Efficiency Design Index (EEDI), either in management phase, adopting the Ship Energy Efficiency Management Plan (SEEMP). In this challenging perspective, several approaches and technologies adopted in land-based engineering can also be advantageous for marine applications. This is the case of the Distributed Energy Resources (DER) solution applied in land-based microgrids, which increases both the system\u2019s efficiency and reliability. This work is primarily focused on methodological aspects related to the adoption of a DER solution on-board cruise ships, with the integration of different energy sources in order to pursue a more flexible, reliable and sustainable management of the ship. In this context, another engineering best practice developed for land-based applications that is further investigated in the paper is related to the on board thermal energy recovery issue, revisited due to the implementation of the DER solution

Particulate cytoplasmic structures with high concentration of ubiquitin-proteasome accumulate in myeloid neoplasms

BACKGROUND: Increased plasma levels of proteasome have been associated with various neoplasms, especially myeloid malignancies. Little is known of the cellular origin and release mechanisms of such proteasome. We recently identified and characterized a novel particulate cytoplasmic structure (PaCS) showing selective accumulation of ubiquitin-proteasome system (UPS) components. PaCSs have been reported in some epithelial neoplasms and in two genetic disorders characterized by hematopoietic cell dysplasia and increased risk of leukemia. However, no information is available about PaCSs in hematopoietic neoplasms. METHODS: PaCSs were investigated by ultrastructural, immunogold, and immunofluorescence analysis of bone marrow (BM) biopsies and peripheral blood (PB) cell preparations of 33 consecutive, untreated, or relapsed patients affected by different hematopoietic neoplasms. BM and PB samples from individuals with non-neoplastic BM or healthy donors were studied as controls. Granulocytes and platelet proteasome content was measured by immunoblotting and plasma proteasome levels by ELISA. RESULTS: PaCSs with typical, selective immunoreactivity for polyubiquitinated proteins and proteasome were widespread in granulocytic cells, megakaryocytes, and platelets of patients with myeloproliferative neoplasms (MPN). In acute myeloid leukemia and myelodysplastic syndromes (MDS), PaCSs were only occasionally detected in blast cells and were found consistently in cells showing granulocytic and megakaryocytic maturation. Conversely, PaCSs were poorly represented or absent in non-neoplastic hematopoietic tissue or lymphoid neoplasms. In MPN granulocytes and platelets, the presence of PaCSs was associated with increased amounts of proteasome in cell lysates. PaCSs were often localized in cytoplasmic blebs generating PaCSs-filled plasma membrane vesicles observable in the BM intercellular space. In MPN and MDS, accumulation of PaCSs was associated with significant increase in plasma proteasome. Immunogold analysis showed that PaCSs of myeloid neoplasia selectively concentrated the chaperone proteins Hsp40, Hsp70, and Hsp90. CONCLUSIONS: PaCSs accumulate in cells of myeloid neoplasms in a lineage- and maturation-restricted manner; in particular, they are widespread in granulocytic and megakaryocytic lineages of MPN patients. PaCSs development was associated with excess accumulation of polyubiquitinated proteins, proteasome, and chaperone molecules, indicating impairment of the UPS-dependent protein homeostasis and a possible link with Hsp90-related leukemogenesis. A mechanism of PaCSs discharge by leukemic cells could contribute to increased plasma proteasome of MPN and MDS