A new guide by ABS focuses on the integration of hybrid electric technologies with conventional power generation to develop a hybrid electric power system (HEPS).
A HEPS utilizes multiple sources of power, both non-traditional sources (e.g. batteries, super-capacitors, fuel cells) and traditional sources (e.g. internal combustion engine driven generator sets, shaft generator driven by main engine).
It is expected that in the future, other alternate electrical power sources such as solar panels, flywheels, and wind (electric) power systems will be mature enough for integration into the electric power generation systems onboard vessels. Vessels with such arrangements also incorporate specialized power and energy management systems that are relatively new in the industry. The application of HEPS onboard the vessel will serve to reduce NOx, SOx and CO2 emissions.
Onboard Documentation
The following documentation and data are to be kept onboard for reference by the operator for system operation and troubleshooting, maintenance, repair, and safety:
- Applicable documents/operation and maintenance manuals such as EMS, PMS, BMS, CMS, FCCMSS, etc.
- Hybrid electric power system operations and maintenance manual;
- Hybrid electric power system functional test schedules;
- Records of safety training of personnel for ships’ handling systems, storage, and equipment associated with fuel cell, battery, and supercapacitor;
- Mitigating plans or control measures for adverse events in case of possible safety critical scenarios including fire and explosion.
Operating Modes
The operational requirements of the HEPS are defined at the beginning of the design process; allocating space, weight, loading profile for the equipment and systems that will be installed during construction and operated during the service life of the vessel.
The basis of design and specifications should be utilized to develop the load analysis and energy/power balance so that requirements for the elements and components of the hybrid electric power system may be developed. The basis of design, specifications and operational plan manuals are to include the plans and data describing all the subsystems integrated, and all the operating modes the vessel is designed for.
Clear identification of parameter values during each mode of operation as well as during transition from one mode to another are to be included.
HEPS Risk Assessment
-General
i) A risk assessment is to be conducted to identify risks associated with the design, installation and safe operation of the electrical power system as new and conventional technologies are integrated onboard. The risk assessment is to demonstrate the vessel’s safety and the continuity of power supply in case of failure of any part of the system. The risks are to be analyzed using acceptable and recognized risk analysis techniques.
ii) Loss of function, component damage, fire, explosion, and electric shock are to be considered as a minimum. The analysis should identify risks that can be eliminated wherever possible.
iii) Risks which cannot be eliminated are to be mitigated, as necessary. Identification of risks, and means by which they are mitigated, are to be documented to the satisfaction of ABS and to the flag Administration if required.
iv) Properly performed studies done early in the design process to identify hazards, risks and failure modes and allow for them to be resolved, and to enhance safety and performance are to be included. Consideration should be given to aligning these studies with modeling and simulation efforts.
-Risk Assessment Techniques
i) The use of risk assessment techniques should be discussed with ABS prior to performing the risk assessment. The risk assessment is to be carried out in accordance with the ABS Guidance Notes on Risk Assessment Applications for the Marine and Offshore Industries.
ii) Several risk assessment techniques may be applied. At the early design stages, a Hazard Identification (HAZID) technique may be conducted to identify potential hazards that could result in consequences to personnel, the environment, and assets. A Hazard and Operability (HAZOP) study may also be conducted to identify and evaluate hazards that may represent risks to personnel or equipment. A Failure Mode and Effects Analysis (FMEA) may also be used to demonstrate that any single failure will not lead to an undesirable event.
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