Shore power

When a ship docks, it no longer needs energy for propulsion. However, ships may still be large consumers of energy when stationary as several of the ship functions are still operating. This includes ventilation/heating/cooling, pumps, control systems and cargo handling systems. Consequently, the generators are running when in port, resulting in local noise and air emissions as well as global climate driving emission. Rather than letting the generators on board make the electricity this can come from shore power.

Applicability and assumptions

Shore power can be installed for all types of vessel and for all ages with need for power in harbour, and has been used for years especially for smaller vessels, but also some larger passenger vessels.

For smaller vessels to draw power from the land based mains supply when docked is not a new phenomenon. Shore power has been used extensively for many years for vessels with moderate power requirements; typically less than 50 to 100 kW. These vessels are capable of making use of normal grid voltage and frequency, and replace the energy from the generators with the shore power with only marginal investments.

For the larger vessels with higher power requirements (100 kW up to 10 to 15 MW) it gets a bit more complicated. To serve these vessels with shore power, dedicated and relatively costly installations are required, both on land and on board the vessels. This may include upgrading the grid capacity, frequency converters and complex high power connectors. Consequently, relatively few vessels and ports are capable of making use of shore power, even though the environmental upsides are considerable. Still, cold ironing may be regarded as a mature technology that has been in regular use since the 1980s.

Shore power may potentially eliminate the local noise and air pollution related to ship activity in a port. Depending on the energy source, it may also contribute positively to the climate driving effects of ship operation, but as an isolated initiative, it is generally not considered to be among the most cost effective climate initiatives.

On the land side, the high power cold ironing system consists of the following:

• High voltage grid to the port
• Frequency and voltage convertors/transformers
• Control panels and connection boxes
• Cable reel and connectorsOn the ship side the following will have to be installed:
• The grid power solution and the frequency converters typically represent the costliest elements on the shore side. Depending on the availability of grid power and the power requirements, the cost of installing shore power on the shore side will vary considerably.

• Transformer
• Power distribution system
• Control panel
• Frequency converter (optional for greater flexibility)
• Connectors and cable reel (optional for greater flexibility)

Table 1 – Typical system specs for the different power requirements

Power Capacity	Typical spec
<100kW	230/400/440V – 50/60hz
100 – 500kW	400/440/690V – 50/60hz
500-1000kW	690V/6.6/11kV – 50/60hz
>1MW	6.6/11kV – 50/60hz

 

Table 2 – Typical system requirements for different ship types and sizes

Vessel types	<= 999	1000 – 4999 GT	5000 – 9999 GT	10000 – 24999 GT	25000 – 49999 GT	50000 – 99999 GT	>= 100000 GT
Oil tankers	230/400/440V – 50/60hz	400/440/690V – 50/60hz	690V/6.6/11kVV – 50/60hz	690V/6.6/11kVV – 50/60hz	690V/6.6/11kVV – 50/60hz	6.6/11kV – 50/60hz	6.6/11kV – 50/60hz
Chemical/product tankers	400/440/690V – 50/60hz	400/440/690V – 50/60hz	690V/6.6/11kVV – 50/60hz	6.6/11kV – 50/60hz	6.6/11kV – 50/60hz
Gas tankers	400/440/690V – 50/60hz	400/440/690V – 50/60hz	6.6/11kV – 50/60hz	6.6/11kV – 50/60hz	6.6/11kV – 50/60hz	6.6/11kV – 50/60hz	6.6/11kV – 50/60hz
Bulk carriers	230/400/440V – 50/60hz	400/440/690V – 50/60hz	400/440/690V – 50/60hz	400/440/690V – 50/60hz	400/440/690V – 50/60hz	690V/6.6/11kVV – 50/60hz
General cargo	230/400/440V – 50/60hz	400/440/690V – 50/60hz	400/440/690V – 50/60hz	400/440/690V – 50/60hz	690V/6.6/11kVV – 50/60hz
Containers vessels		400/440/690V – 50/60hz	400/440/690V – 50/60hz	690V/6.6/11kVV – 50/60hz	6.6/11kV – 50/60hz	6.6/11kV – 50/60hz	6.6/11kV – 50/60hz
Ro Ro vessels	230/400/440V – 50/60hz	400/440/690V – 50/60hz	400/440/690V – 50/60hz	690V/6.6/11kVV – 50/60hz	690V/6.6/11kVV – 50/60hz	6.6/11kV – 50/60hz
Reefers	230/400/440V – 50/60hz	400/440/690V – 50/60hz	400/440/690V – 50/60hz	690V/6.6/11kVV – 50/60hz
Passengers vessels	230/400/440V – 50/60hz	400/440/690V – 50/60hz	400/440/690V – 50/60hz	690V/6.6/11kVV – 50/60hz	6.6/11kV – 50/60hz	6.6/11kV – 50/60hz	6.6/11kV – 50/60hz
Offshore supply vessel	230/400/440V – 50/60hz	400/440/690V – 50/60hz	6.6/11kV – 50/60hz
Other offshore service vessels	230/400/440V – 50/60hz	400/440/690V – 50/60hz	690V/6.6/11kVV – 50/60hz	690V/6.6/11kVV – 50/60hz	690V/6.6/11kVV – 50/60hz	690V/6.6/11kVV – 50/60hz	690V/6.6/11kVV – 50/60hz
Other activities	230/400/440V – 50/60hz	400/440/690V – 50/60hz	690V/6.6/11kVV – 50/60hz	6.6/11kV – 50/60hz	6.6/11kV – 50/60hz	6.6/11kV – 50/60hz	6.6/11kV – 50/60hz
Fishing vessels	230/400/440V – 50/60hz	400/440/690V – 50/60hz	6.6/11kV – 50/60hz

 

Cost of implementation

Table 3 – Estimated cost for implementing shore power on board vessels

Investment cost for vessel (USD)	1000 – 4999 GT	5000 – 9999 GT	10000 – 24999 GT	25000 – 49999 GT	50000 – 99999 GT	>= 100000 GT
Crude tankers	$50 000 – $350 000	$100 000 – $400 000	$100 000 – $400 000	$100 000 – $400 000	$300 000 – $750 000	$300 000 –$750 000
Chemical / product tankers	$50 000 – $350 000	$100 000 – $400 000	$300 000 – $750 000	$300 000 – $750 000
Gas tankers	$50 000 – $350 000	$300 000 – $750 000	$300 000 – $750 000	$300 000 – $750 000	$300 000 – $750 000	$300 000 –$750 000
Bulk carriers	$50 000 – $350 000	$50 000 – $350 000	0,5 – 3 Mill	0,5 – 3 Mill	$100 000 – $400 000
General cargo	$50 000 – $350 000	$50 000 – $350 000	0,5 – 3 Mill	$100 000 – $400 000
Container vessels	$50 000 – $350 000	$50 000 – $350 000	$100 000 – $400 000	$300 000 – $750 000	$300 000 – $750 000	$300 000 –$750 000
Ro Ro vessels	$50 000 – $350 000	$50 000 – $350 000	$100 000 – $400 000	$100 000 – $400 000	$300 000 – $750 000
Reefer	$50 000 – $350 000	$50 000 – $350 000	$100 000 – $400 000
Passenger ship	$50 000 – $350 000	$50 000 – $350 000	$100 000 – $400 000	$300 000 – $750 000	$300 000 – $750 000	$300 000 –$750 000
Offshore supply ship	$50 000 – $350 000	$100 000 – $400 000
Other offshore service ships	$50 000 – $ 350 000	$100 000 – $400 000	$100 000 – $400 000	$100 000 – $400 000	$100 000 – $400 000	$100 000 – $400 000
Other activities	$50 000 – $ 350 000	$100 000 – $400 000	$300 000 – $750 000	$300 000 – $750 000	$300 000 – $750 000	$300 000 –$750 000
Fishing vessels	$50 000 – $ 350 000	$100 000 – $400 000

 

The cost of adapting a vessel for shore connection depends on the plant design and the possibility of varying the voltage and frequency range when needed. Further, it is important to consider that these costs are only for the vessel, not for the implementation at the port side.

Reduction potential

The reduction potential is 50% to 100% in port for the electrical motors on board.

Other References

1. Onshore Power Supply / Independent non-profit website established by the World Ports Climate Initiative (WPCI)
2. Commission Recommendation / EU library of documents related to ports and emissions
3. ISO – Electrical installations in ships / The ISO is a non-governmental organization that forms a bridge between the public and the private sectors. The ISO in co-operation with the IEC and IEEE is currently preparing a standard for High Voltage Shore Connection systems.