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Plug and play – Four things about reducing emissions and fuel costs with shore power

16th May 2023

Ships typically burn fossil fuels while alongside berth to power their systems, resulting in emissions of greenhouse gases, particulate matter, and other pollutants. With shore power infrastructure available at the port and the right equipment and systems onboard vessels, instead of burning fossil fuel in its auxiliary engines to meet this demand, a vessel can simply plug into the local grid. With many countries aiming today aiming up to 50% of the electricity from renewable sources like wind, hydro or solar power, is making shore power a far greener option. Depending on the vessel type and trade the environmental impact can be huge especially where urban populations live in a very close vicinity of the ports. The electric power consumption of a large cruise liner, ROPax or a container vessel can be equivalent to that needed by a small city.

1.GHG reduction potential of shore-to-ship power

  • The emissions avoided depend on the fuel used. Electricity generation using the auxiliary engines on ships emit about (the emissions factor also depends on load and sizing of the engines):
    • 690gCO2 /kWh for marine gas oil.
    • 722gCO2 /kWh for heavy fuel oil.
  • The emissions avoided also depend on the electricity grid emissions factor:
    • With the EU emission grid factor of 390gCO2/kWh, there is a CO2 saving of about 300gCO2/kWh or 40%.
    • All emissions could be abated if electricity is generated using renewables.

2. It is a matter of compliance, not ROI – Ports are now investing in shore power facilities and it will gradually become mandatory for vessels to use them. Fit for 55, deal on new EU rules for cleaner fuels, require Containerships and passenger ships at major EU ports to use on shore power supply as of 2030. Regulators around the world are taking action to secure a level playing field and most governments are now making it mandatory for ports to install shore power facilities and even co-funding projects as part of their decarbonisation efforts.

3. Port-side solutions need to be customized – Shore-to-ship power at ports needs to be designed to accommodate characteristics of each vessel segment (e.g. cruise ships, ferries, cargo ships), which can differ substantially:

  • Voltage: Ships’ voltage levels can range from low (400V-690V) to high (6.6 or 11kV) voltage. A transformer is needed either on each ship or on the port side to match the different voltage levels and to ensure galvanic isolation between ships that are connected simultaneously at a shore power facility.
  • Frequency: the majority of ships operate with 60 Hz, with some at 50 Hz, while onshore power frequency varies depending on countries. European countries, for example, operate at 50 Hz. A frequency converter is needed to match the onshore power frequency to the onboard power system frequency, and it is one of the biggest cost drivers in a shore power facility.
  • Power demand: depends on vessel type. Up to 3 MVA for ferry/RORO, 7.5 MVA for container ships and 20 MVA for cruise vessels. Berths need to have the appropriate infrastructure to meet the maximum power demand. Shore-to-ship power may not be suitable in regions that do not have stable electricity grids.

4. International Electrotechnical Commission (IEC) standards already exist – As most ports will be hosting different vessels and a vessel will be visiting various ports when in service, a common standard is needed to make sure vessels can plug in whichever port they call or sailing to. The IEC 80005-1 describes a high voltage solution for container, RoRo and cruise vessels and LNG carriers and tankers, and this standard can also be applied to pure car truck carriers, RoPax vessels such as ferries and super yachts. The IEC 80005-3 standard regulates a low voltage solution for all vessels that need up to 1 MW shore power, for example bulkers or offshore vessels.