What is Onshore Power Supply (OPS)?
Ships can shut down their engines while berthed and plug into an onshore power source, the ship’s power load is transferred to the onshore power supply without disruption to onboard services. Emissions to the local surroundings are eliminated
Onshore power supply (OPS) is also know as Shore side electricity (SEE), Shore Connection, Shore-to-ship Power, Cold ironing, Alternative Maritime Power, etc.
Shore power is especially applicable to ships operating on dedicated routes and vessels that consume large amounts of power and emit high levels of air pollutants when berthed. Typical vessel types include ferries, cruise ships, LNG carriers, tankers and container ships.
In the figure below a general design of high-voltage OPS facilities is given. An electrical cable is extended from the pier and plugged into the ship’s receptacle to supply power to operate the machinery, allowing the ship to shut down the diesel engines that normally drive the electrical generators.
International standards and OPS facilities
Shore-to-ship power standards overview:
IEC / ISO / IEEE 80005-1, High Voltage shore side electricity (up to 20 MVA per vessel)
IEC / ISO / IEEE 80005-2, Communication Protocol
IEC / ISO / IEEE 80005-3, Low Voltage shore side (typically less than 1 MVA).
IEC: International Electrotechnical Commission; IEEE: Institute of Electrical and Electronics Engineers; ISO: International Standardisation Organisation
Since August 2012 there is an international standard for the plug used when connecting a ship. From a technical perspective, the various implementations worldwide have proven the viability of the technology. The frequency conversion issue (50hHz versus 60Hz) has been covered by main manufacturers since several years and a global standard provides worldwide guidance on safety and compatibility (standardised plugs and cables). This High Voltage Shore Connection standard has been validated in August 2012 by IEC, ISO and IEEE (80005-1) and enables to cover most of European ship traffic (Roro, Ferry, containers, tankers, LNG and cruise ships).to the port OPS facility. The plug is for high-voltage connection systems (HVSC) and the standard is named ISO/IEC/IEEE 80005-1. According to the IEC the standard is applicable to the design, installation and testing of HVSC systems and addresses among other things shore-to-ship connection and interface equipment. It does not apply to the electrical power supply during docking periods, e.g. dry docking and other out of service maintenance and repair.
The standard 80005-2 regulates the communication between ship and shore. This standard allows the onshore part of SSE to be remote-controlled from the ship. The standard 80005-3 regulates Low Voltage shore side electricity.
Most components used in OPS installations are standard and widely used in various types of electrical equipments in other industries. Thereby, there is no technical barrier anymore to the development of OPS in Europe.
What investments are required on shore side to install SSE infrastructure?
A OPS installation typically requires a building, or a shelter, containing the necessary technical equipment that include switchgear, transformers and frequency converters which aim is to adapt the shore electrical characteristics to the ship's ones (voltage, frequency..etc.). According to the ISO IEC IEEE 80005-1 standard, for cruise, ferry, Roro & Ropax, and cargo ships, the cables management system should also be on the shore side.
The cost of an investment in OPS is likely to be very different from one port to another. It mainly depends on the ship type and the power requirement: the higher the power demand is, more expensive it will be. Hence, an OPS for a cruise berth (requiring up to 20MVA) is likely to be more expensive than an installation for a ferry.
What investments are required on ship side to enable them to plug into OPS infrastructure?
As for ports, rarely are two ships identical: it is therefore difficult to describe any specific technical requirements applying equally to all ships. However, most ships’ retrofits require modification of the main switchboard, a new receiving circuit breaker close to the power receiving point, power socket(s) and an upgrade of the ship power management system. In addition, some mechanical modifications are needed (build a door on the hull to receive the socket outlet as well as the cables) and in case of a container ship, the cable management shall be installed on board instead of the socket(s) (based on ISO IEC IEEE 80005-1 standard). Finally, the ship owner will have to request the certification of the installation by the corresponding classification societies. A very rough thumb value of the investment costs including cabling would be: 500K€ to 1M€. But it must be underlined that this investment is only needed in the case of retrofit of ships. But OPS is nowadays already installed in the majority of newly built ships, directly during the construction phase, which drastically reduces the costs for ship owners.
Application and advantages of OPS
When berthed, ships require electricity to support activities like loading, unloading, heating, lighting and operation of other technical installations. Normally, the ships’ propulsion engines are turned o when berthed and the power needed is provided by auxiliary engines that are running on diesel oil or other fossil-based fuel. Most of the new cruise ships, which are the biggest single sources for air emission in a port, use diesel electric propulsion system and get the all the electricity they need from the same generators. Exhausts from the auxiliary engines affect the environment negatively both locally and globally by emissions of CO2 and other air pollutants.
Since 2010 a European Union directive (2005/33/EC) limits the sulphur content in marine fuel to 0.1% (from 1%) for ships at berth (see directive for exemptions) in order to reduce the emissions discharge from vessels. Ships can either choose to use an alternative ship fuel while at berth, or to connect to shore-side electricity, that is, OPS.
The use of OPS reduces the negative environmental aspects of ships, such as noise and air pollution, since the ships’ auxiliary engines can be switched off. Moreover, implementation of OPS provides an opportunity not only to improve air quality, but also to reduce emissions of CO2, one of the main contributors to global warming.
General design of high-voltage OPS facilities. An electrical cable is extended from the pier and plugged into the ship’s receptacle to supply power to operate the machinery, allowing the ship to shut down the diesel engines that normally drive the electrical generators.
Classification and verification of Onshore Power Supply installations and connections.
DNV GL is an international accredited registrar and classification society headquartered in Høvik, Norway. It is the largest classification company for shipping globally. A section on OPS is included in its RULES FOR CLASSIFICATION SHIPS (Part 6 Additional class notations, Chapter 7 Environmental protection and pollution control, Section 5 Electrical Shore Connections (edition July 2019).
The objective of the additional class notation Shore power is to provide requirements for a transfer of power utilizing an electrical shore connection while in port.
Additional class notation Shore power provides requirements for the design of electrical shore connections, the ship side installation of necessary equipment and the verification of the installations.
The system design comprises the following aspects:
— system functionality of the electrical shore connection as a total system. In addition, requirements to circuit breakers, earthing switches and protective functions are given
— control systems and control system interface between the shore and the vessel. Requirements are given for necessary functionality. However, the physical installations on shore are not covered by these rules
— ship side electrical equipment and installations. However, only specific requirements related to electrical shore connections are given. Generally, equipment and installations shall comply with relevant parts of Pt.4 Ch.8.
Operational characteristics and requirements with respect to power availability during loading and unloading are not within the scope of these rules. Shore side electrical equipment and installations, apart from the functional requirements to the installation, are governed by national regulations, and are not a part of these rules. The additional class notation Shore power is not intended for shore connections used during service and maintenance docking.The additional class notation Shore power applies to vessels utilizing electrical shore connections while in port and is mandatory for vessels with high voltage shore connection and low voltage shore connection with power rating greater than or equal to 1 MVA. This is applicable for shore power supplying the distribution grid and/or charging electrical energy storage systems onboard the vessel.