Shipping: Switch off the generators!

Moor the ship at the berth, shut down the engines, connect the shore power cable – this is standard practice for recreational boats, but still the exception in commercial shipping. Only a limited number of seaports worldwide currently offer cargo and passenger vessels the option of covering their electricity needs during port stays via a shore connection, thereby avoiding emissions and noise. However, the number is steadily increasing. At the same time, fleets themselves must be made capable of using shore power.

Most ships still run on heavy fuel oil, one of the dirtiest fuels available. Taken together, maritime shipping accounts for roughly three percent of global CO2-emissions. These emissions not only harm the global climate but also severely degrade air quality in port areas. While at berth, onboard generators – typically powered by the same fuel as the main engines – produce the required electricity. In the case of cruise ships, this demand can equal that of a small town.

Internationally, the goal is to gradually reduce greenhouse gas emissions from shipping, with net-zero emissions targeted by 2050. Emissions in ports account for only a relatively small share of the total: according to the German Shipowners’ Association (VDR), cargo vessels generate about six to ten percent of their operating CO2-emissions while in port. For cruise ships, however, the share is significantly higher. The largest German operator, AIDA Cruises, states that its ships spend on average about 40 percent of their voyage time in port. In addition, port emissions – beyond greenhouse gases, including pollutants such as nitrogen oxides and sulfur oxides as well as noise – directly affect large numbers of people. Shore power therefore contributes to emission reduction at a particularly critical point.

So far, however, only about three percent of ports worldwide offer shore power, according to the International Chamber of Shipping (ICS). The situation in the cruise sector is even more limited: industry figures indicate that just over 20 cruise ports worldwide are equipped with shore power – less than one percent. Three of these ports are in Germany: Hamburg, Kiel, and Rostock-Warnemünde.

China is a leader in shore power supply for container ports. Several ports in North America and Europe also provide the necessary infrastructure, and in California shore power has even been mandatory since 2023. In Germany, the port of Hamburg is at the forefront: since May 2024, the country’s largest seaport has offered shore power not only for cruise ships but also for container vessels. Since the end of 2025, appropriate systems have been available at all cruise and major container terminals.

According to Hanno Bromeis, who is responsible for shore power and electrification at the Hamburg Port Authority, building this infrastructure costs between €10 million and €20 million per installation. Half of the cost is borne by the City of Hamburg, while the other half is covered by federal funding. The electricity supplied comes 100 percent from renewable energy sources. “Only then does shore power contribute to decarbonizing the overall system,” says Bromeis. In the future, Hamburg also plans to establish direct local supply on port premises using wind turbines, photovoltaic systems, and large-scale energy storage.

For shipping companies, the transition to shore power also involves considerable effort. “Ships must be equipped with transformers, specialized safety systems, and the connection interface,” explains VDR spokesperson Carsten Duif. “In addition, complex modifications to the onboard power system are required – including control systems to ensure a seamless and safe transition from ship diesel generators to shore power.” Depending on the ship type, age, and technical conditions, the cost can reach up to one million US dollars.

Shipping companies that use shore power for their vessels pay both for the electricity consumed per kilowatt-hour and a service fee. According to Bromeis, this fee is around €4,000 to €5,000 for container ships and up to €7,000 for cruise ships. Electricity is purchased on the spot market, which causes prices to fluctuate significantly. “There’s no alternative,” says Bromeis. “Demand can range from zero to the consumption of a small town – no fixed tariff could cover that.”

At present, many shipping companies are nevertheless pushing ahead with retrofitting their existing fleets and equipping new vessels with shore power capability from the outset. At Germany’s largest container shipping company, Hapag-Lloyd, this is now standard for new builds, according to the company. Overall, about 30 percent of its fleet is currently equipped with the technology. According to the VDR, no comprehensive figures are available for the global situation. For Hamburg, Bromeis estimates that roughly 50 to 60 percent of large ships calling at the port are capable of using shore power. A similar trend can be observed in the cruise industry. According to the international trade association CLIA (Cruise Lines International Association), nearly half of its member fleets can already connect to shore power, and this share is expected to rise to almost three-quarters by 2028.