Safety dynamics of ship’s energy sources
The transport industry is focusing on alternative energy sources due to a rise in public willingness and the need to partake in global efforts to reduce harmful emissions.
27.05.2022
The United Nations Sustainable Development Goals (UN SDGs) have driven political pressure across all sectors including maritime. The International Maritime Organization (IMO), the technical agency under the UN developing safety and security standards for the maritime industry, has also pledged its commitment to decarbonise shipping in an effort to contribute to this united worldwide endeavour.
For decades, the maritime industry has dealt with widely available carbon-based fuels which are operated under normal temperature and pressure.
For the maritime industry, the visions and strategies for environmental protection have been developed and include the use of alternative energy sources. Taking into account the fact that there is more than one type of energy source on a ship for safeguarding propulsion and manoeuvring, especially during emergency operations, it is an urgent safety matter to have a clear understanding of the differences amongst energy sources used. This is a historic transition where numerous uncertainties and risk may emerge.
These developments require further consideration for the safety of the human element who are involved and affected across the whole sector in this transition. The need for safety assurances, proper training, and familiarisation must be recognised and implemented to guarantee that all personnel are able to return back home safe.
Seafarers, firefighting personnel, search and rescue personnel, pilots, dockers, bunkering handling personnel and tugboat personnel are directly and indirectly affected and involved in on-the-job operations throughout this transition.
Companies, authorities, suppliers, protection and indemnity insurance providers, and recognised organisations including unions are to ensure the safety of those mentioned above.
Maritime education and training institutes, medical practitioners, and security enforcing bodies are to ensure safety and security culture is firmly embedded in the whole system.
For all stakeholders, appropriate competencies and establishing a safety culture are essential for health and safety for both the human element and the environment.
Introducing a new type of energy source encompasses the entire life cycle from manufacturing, transporting, bunkering, storage, and energy processing onboard.
To protect human lives in this transition, it is necessary to have a clear vision of the safety dynamics associated with each energy source. This can be accomplished by acquiring the correct knowledge about the energy sources being used and obtaining the proper competencies necessary for the whole operation, including emergency circumstances. Competencies must therefore include knowledge of operations that may include, inter alia, extreme temperatures and pressures, toxicity, corrosiveness and high voltage, all of which can inflict harm and/or accidents.
The purpose of this document is to highlight the imminent need to put in place measures for those involved in direct on-the-job operations and provide recommendations to close the safety and competency gaps that may exist.
When introducing alternative energy sources, the following are crucial:
• A robust training scheme that guarantees the highest level of safety culture;
• appropriate training that covers communication, risk analysis, operation and emergency situations;
• knowledge about construction and design and relevant regulations;
• adequate fire detection and fire-fighting equipment;
• availability of proper lifesaving appliances; and
• provisions of adequate personal protection equipment for all personnel.
Part II
A table who according to the ITF MSC SG TOR
- Identify technical characteristics of fuels and energy sources which produce less emissions;
- Identify hazards related to safety and health and operation, including bunkering and storage;
- Identify safety and health issues for lives and cargo on board related to construction and design of a ship; and
- Recommendations to close the safety gap.
Attachments
a) The Scrubber
b) The Fuel Cell
This document does not contain renewable energy sources, such as solar and wind power.
Be aware on a ship there will always be several types of energy sources that require different competence and fire extinguishing equipment
Energy efficiency:
Fuel cell is around 60 %
Combustion engine is about 35 %
Steam turbine is about 50 %
Thorium Molten salt Reactor is about 50 %
Definition of flash point: The lowest temperature at which vapors above a volatile combustible substance ignite in air when exposed to flame
* Differences between liquid and gas and terms used, such as storage temperature and vapor temperature
ITF: WHAT IS THE IGF CODE AND HOW DOES IT AFFECT ME? Alternative ship fuels – status and outlook
ITF MSC suggest a change/ amendment in STCW as following in Reg. I/1.1.15 Definitions and Clarifications
Propulsion power means the total maximum continuous rated output power for propulsion and manoeuvring, in kilowatts, of all the ship’s main propulsion machinery regardless of energy source which appears on the ship’s certificate of registry or other official document.
a) The Scrubber/Exhaust Gas Cleaning System (EGCS)
There are 3 types of wet scrubbers: open-loop, closed loop or compact/ hybrid using both open/closed loop adopted by the maritime industry for removal of sulphur oxides (SOx) and particulate matter in the exhaust air.
The closed loop: is equipped with a storage tank that is holding the remaining exhaust “mud” (sludge) and released ashore when available to convenient port facilities
Open loop: is equipped with a sludge tank and a washwater treatment tank that dilutes the washwater before it is drained out at the bottom of the scrubber, while the clean gas continues through the packing via the demister unit, before it is released into the atmosphere.
The result is an efficient and well tested cleaning process with no moving parts.
Process: Sodium Hydroxide NaOH (Caustic Soda as alkaline) + seawater (including any type of seawater; low alkaline and saline water) sprayed inside the chamber of the scrubber right after combustion in 3 sequences: seawater – NaOH - seawater.
System used natural seawater in both open and closed-loop operation and could boost with alkali to reach pH>6 at outlet.
All exhaust sources on board can be connected to only one common EGCS unit, or individual scrubbers for each exhaust source (ME, AE, boiler)
KEY FEATURES
No back pressure
• No fuel penalty
• AE’s can start connected to EGC unit(s)
• No restrictions running AE’s in part load – no impact on engine parameters (EIAPP)
• Boilers connected
Closed loop/open loop operation
• Open loop 0,5% Sulphur – sea water only when Sulphur < 3,5%
• Open loop 0,1% Sulphur – sea water + NaOH dosing; can transit any water – no alkalinity restrictions
• Closed loop – sea water + NaOH dosing; only required where zero discharge is called for pH
• Open loop 0,5% Sulphur – process water + cooling water + dilution device
• Open loop 0,1% Sulphur plus NaOH (pH 6,5 at 4m or pH 6 at overboard)
b) The Fuel Cell
A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen) and an oxidizing agent (often oxygen into electricity through a pair of redox reactions.
Fuel cells are different from most batteries in requiring a continuous source of fuel and oxygen (usually from air) to sustain the chemical reaction, whereas in a battery the chemical energy usually comes from metals and their ions or oxides that are commonly already present in the battery, except in flow batteries. Fuel cells can produce electricity continuously for as long as fuel and oxygen are supplied.
The first commercial use of hydrogen–oxygen fuel cell was in 1932. The alkaline fuel cell, also known as the Bacon fuel cell after its inventor, has been used in NASA space programs since the mid-1960s to generate power for satellites and space capsules. Since then, fuel cells have been used in many other applications. Fuel cells are used for primary and backup power for commercial, industrial and residential buildings and in remote or inaccessible areas. They are also used to power fuel cell vehicles, including forklifts, automobiles, buses, trains, boats, motorcycles and submarines.
There are many types of fuel cells, but they all consist of an anode, a cathode, and an electrolyte that allows ions, often positively charged hydrogen ions (protons), to move between the two sides of the fuel cell. At the anode a catalyst causes the fuel to undergo oxidation reactions that generate ions (often positively charged hydrogen ions) and electrons. The ions move from the anode to the cathode through the electrolyte. At the same time, electrons flow from the anode to the cathode through an external circuit, producing direct current electricity. At the cathode, another catalyst causes ions, electrons, and oxygen to react, forming water and possibly other products. Fuel cells are classified by the type of electrolyte they use and by the difference in startup time ranging from 1 second for proton-exchange membrane fuel cells (PEM fuel cells, or PEMFC) to 10 minutes for solid oxide fuel cells (SOFC). A related technology is flow batteries, in which the fuel can be regenerated by recharging. Individual fuel cells produce relatively small electrical potentials, about 0.7 volts, so cells are "stacked", or placed in series, to create sufficient voltage to meet an application's requirements. In addition to electricity, fuel cells produce water, heat and, depending on the fuel source, very small amounts of nitrogen dioxide and other emissions. The energy efficiency of a fuel cell is generally between 40 and 60%; however, if waste heat is captured in a cogeneration scheme, efficiencies of up to 85% can be obtained.