Ultracapacitors for port crane applications: Sizing and techno-economic analysis

The use of energy storage with high power density and fast response time at container terminals (CTs) with a power demand of tens of megawatts is one of the most critical factors for peak reduction and economic benefits. Peak shaving can balance the load demand and facilitate the participation of small power units in generation based on renewable energies. Therefore, in this paper, the economic efficiency of peak demand reduction in ship to shore (STS) cranes based on the ultracapacitor (UC) energy storage sizing has been investigated. The results show the UC energy storage significantly reduce the peak demand, increasing the load factor, load leveling, and most importantly, an outstanding reduction in power and energy cost. In fact, the suggested approach is the start point to improve reliability and reduce peak demand energy consumption

Modeling and Real-Time Scheduling of DC Platform Supply Vessel for Fuel Efficient Operation

DC marine architecture integrated with variable speed diesel generators (DGs) has garnered the attention of the researchers primarily because of its ability to deliver fuel efficient operation. This paper aims in modeling and to autonomously perform real-time load scheduling of dc platform supply vessel (PSV) with an objective to minimize specific fuel oil consumption (SFOC) for better fuel efficiency. Focus has been on the modeling of various components and control routines, which are envisaged to be an integral part of dc PSVs. Integration with photovoltaic-based energy storage system (ESS) has been considered as an option to cater for the short time load transients. In this context, this paper proposes a real-time transient simulation scheme, which comprises of optimized generation scheduling of generators and ESS using dc optimal power flow algorithm. This framework considers real dynamics of dc PSV during various marine operations with possible contingency scenarios, such as outage of generation systems, abrupt load changes, and unavailability of ESS. The proposed modeling and control routines with real-time transient simulation scheme have been validated utilizing the real-time marine simulation platform. The results indicate that the coordinated treatment of renewable based ESS with DGs operating with optimized speed yields better fuel savings. This has been observed in improved SFOC operating trajectory for critical marine missions. Furthermore, SFOC minimization at multiple suboptimal points with its treatment in the real-time marine system is also highlighted

Feasibility Study of a Modular Multi-Purpose Frigate with an Integrated Power & Energy System

This paper presents a feasibility study of a modular multi-purpose frigate with an integrated power and energy system (IPES) and a Combined Diesel Electric and Gas (CODLAG) propulsion system. The modular design offers greater flexibility, enabling the vessel to perform a wider range of missions thanks to innovative hull form and a large capacity for carrying a containerized payload. The study evaluates also the feasibility and potential benefits of two possible configurations for the Energy Storage System (ESS) integration in the onboard IPES, enabled by the specific ship design. The utilization of peak shaving technology reliying on supercapacitors has a limited impact on the ship in terms of weight and volume, thus being the most appropriate solution for CODLAG frigates. Conversely, Li-ion batteries can enable zero-emission mode. A large ESS capacity can be integrated onboard in the available weight and volume margins (enabled by the specific ship design), aimed at improving energy efficiency in port, manoeuver, and combat modes (by avoiding non-optimal load rates on generators)

Derivation of Power System Module Metamodels for Early Shipboard Design Explorations

The U.S. Navy is currently challenged to develop new ship designs under compressed schedules. These ship designs must necessarily incorporate emerging technologies for high power energy conversion in order to enable smaller ship designs with a high degree of electrification and next generation electrified weapons. One way this challenge is being addressed is through development of collaborative concurrent design environment that allows for design space exploration across a wide range of implementation options. The most significant challenge is assurance of a dependable power and energy service via the shipboard Integrated Power and Energy System (IPES). The IPES is largely made up of interconnected power conversion and distribution equipment with allocated functionalities in order to meet demanding Quality of Power, Quality of Service and Survivability requirements. Feasible IPES implementations must fit within the ship hull constraints and must not violate limitations on ship displacement. This Thesis applies the theory of dependability to the use of scalable metamodels for power conversion and distribution equipment within a collaborative concurrent design environment to enable total ship set-based design outcomes that result implementable design specifications for procurement of equipment to be used in the final ship implementation

Derivation of Power System Module Metamodels for Early Shipboard Design Explorations

The U.S. Navy is currently challenged to develop new ship designs under compressed schedules. These ship designs must necessarily incorporate emerging technologies for high power energy conversion in order to enable smaller ship designs with a high degree of electrification and next generation electrified weapons. One way this challenge is being addressed is through development of collaborative concurrent design environment that allows for design space exploration across a wide range of implementation options. The most significant challenge is assurance of a dependable power and energy service via the shipboard Integrated Power and Energy System (IPES). The IPES is largely made up of interconnected power conversion and distribution equipment with allocated functionalities in order to meet demanding Quality of Power, Quality of Service and Survivability requirements. Feasible IPES implementations must fit within the ship hull constraints and must not violate limitations on ship displacement. This Thesis applies the theory of dependability to the use of scalable metamodels for power conversion and distribution equipment within a collaborative concurrent design environment to enable total ship set-based design outcomes that result implementable design specifications for procurement of equipment to be used in the final ship implementation

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

Control and Optimization of Energy Storage in AC and DC Power Grids

Energy storage attracts attention nowadays due to the critical role it will play in the power generation and transportation sectors. Electric vehicles, as moving energy storage, are going to play a key role in the terrestrial transportation sector and help reduce greenhouse emissions. Bulk hybrid energy storage will play another critical role for feeding the new types of pulsed loads on ship power systems. However, to ensure the successful adoption of energy storage, there is a need to control and optimize the charging/discharging process, taking into consideration the customer preferences and the technical aspects. In this dissertation, novel control and optimization algorithms are developed and presented to address the various challenges that arise with the adoption of energy storage in the electricity and transportation sectors. Different decentralized control algorithms are proposed to manage the charging of a mass number of electric vehicles connected to different points of charging in the power distribution system. The different algorithms successfully satisfy the preferences of the customers without negatively impacting the technical constraints of the power grid. The developed algorithms were experimentally verified at the Energy Systems Research Laboratory at FIU. In addition to the charge control of electric vehicles, the optimal allocation and sizing of commercial parking lots are considered. A bi-layer Pareto multi-objective optimization problem is formulated to optimally allocate and size a commercial parking lot. The optimization formulation tries to maximize the profits of the parking lot investor, as well as minimize the losses and voltage deviations for the distribution system operator. Sensitivity analysis to show the effect of the different objectives on the selection of the optimal size and location is also performed. Furthermore, in this dissertation, energy management strategies of the onboard hybrid energy storage for a medium voltage direct current (MVDC) ship power system are developed. The objectives of the management strategies were to maintain the voltage of the MVDC bus, ensure proper power sharing, and ensure proper use of resources, where supercapacitors are used during the transient periods and batteries are used during the steady state periods. The management strategies were successfully validated through hardware in the loop simulation