What shore power is
Shore power lets a ship switch off its auxiliary engines at the berth and take its electricity from the land grid instead. The same idea goes by several names: onshore power supply (OPS), cold ironing, shore side electricity and, in North America, alternative maritime power (AMP).
A ship at berth still needs power for lighting, ventilation, refrigeration, cargo handling and, on a cruise ship, a small town of passengers. Without shore power that load runs on diesel generators next to the quay. With it, the emissions and noise move off the waterfront and the carbon footprint follows the mix of the local grid.
How a shore power connection works
A connection has three parts. On land, the port brings a grid connection to a substation, converts frequency where needed and delivers power to the quay through a connection point. A cable management system, fixed or mobile, carries the cables to the ship. On board, the vessel needs a connection panel and switchboard that can accept the supply.
Europe's grid runs at 50 Hz while most ocean going ships run at 60 Hz, so many installations include frequency converters. Large vessels connect at high voltage, typically 6.6 kV or 11 kV, while smaller craft and many inland vessels use low voltage. Demand ranges from well under 1 MW for small vessels to more than 10 MW for the largest cruise ships, which is why grid capacity, not the plug, is usually the hardest part of a project.
The standards: IEC/IEEE 80005
The international standard family is IEC/IEEE 80005. Part 1 covers high voltage shore connection systems for ships such as cruise, container, ro-ro and tankers. Part 2 covers the data communication between ship and shore. Part 3 covers low voltage connections for smaller vessels.
Following the standard is what makes a ship from one fleet able to plug in at a port built by another supplier. Interoperability between ship, cable system and shore is still where many first connections are tested and commissioned.
AFIR: what EU ports must provide by 2030
The Alternative Fuels Infrastructure Regulation, Regulation (EU) 2023/1804, requires maritime ports on the TEN-T network to provide shore power by the end of 2029. The obligation covers seagoing container ships and passenger ships, including ro-pax, high speed passenger craft and cruise ships, of more than 5,000 gross tonnes.
Ports must be able to supply at least 90 percent of the calls by those ships, where traffic passes set thresholds: on average more than 100 container ship calls, 40 ro-pax or high speed craft calls, or 25 other passenger ship calls a year over the previous three years. Inland ports on the TEN-T network have their own shore power obligations.
FuelEU Maritime: when ships must plug in
FuelEU Maritime, Regulation (EU) 2023/1805, puts the matching duty on ships. From 1 January 2030, container and passenger ships above 5,000 gross tonnes must connect to shore power while at berth in the TEN-T ports covered by AFIR, and from 2035 in other EU ports that offer it. Exceptions include short stays of under two hours and ships using an equivalent zero emission technology at berth.
Together the two regulations close the loop that held shore power back for years: ports waited for ships that could connect, and shipowners waited for ports that could supply. Emissions trading adds a cost to every tonne burned at berth, since shipping entered the EU ETS in 2024.
Grid capacity, cost and funding
The cost of a shore power project sits mostly on the land side: the grid connection, substations, frequency conversion and civil works along the quay. Grid capacity is the most common constraint, because a busy cruise or ferry terminal can need as much power as a small town at short notice, and new connections can take years.
Ports are answering with battery storage, microgrids and onsite generation to manage peaks, and with EU funding such as the Connecting Europe Facility and its alternative fuels facility. The open questions are commercial: who pays for capacity that is idle between calls, and at what price shore power can compete with fuel burned at berth.
Questions, answered
What is the difference between shore power, OPS and cold ironing?+
There is none in practice. Shore power, onshore power supply (OPS), cold ironing and shore side electricity all describe a ship taking electricity from the land grid at berth instead of running its own engines.
Which ships must use shore power in the EU?+
Under FuelEU Maritime, container and passenger ships above 5,000 gross tonnes must connect at berth in TEN-T ports covered by AFIR from 1 January 2030, with limited exceptions such as stays under two hours.
What does AFIR require of ports?+
TEN-T maritime ports must provide shore power covering at least 90 percent of calls by large container and passenger ships by the end of 2029, where those ships call more often than the regulation's thresholds.
What is IEC/IEEE 80005?+
It is the international standard family for shore connections: Part 1 for high voltage systems, Part 2 for ship to shore data communication and Part 3 for low voltage systems.
Why is grid capacity the main challenge?+
Large ships can draw several megawatts each, and a terminal with several berths may need tens of megawatts at peak. Reinforcing the grid to the quay is often the slowest and most expensive part of a project.
