Nature and Biodiversity

How PortMiami is using 'cold ironing' to reduce cruise ship emissions

Two cruise ships in port, illustrating the potential of cold ironing

Cold ironing in ports could significantly reduce ship greenhouse gas emissions. Image: Stephanie Klepacki on Unsplash

Lisa Chamberlain
Communication Lead, Urban Transformation, World Economic Forum
Jonathan Walter
Writer and Editor, World Economic Forum
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Climate and Nature

This article is part of: Centre for Urban Transformation
  • The cruise industry is making a post-pandemic comeback, putting pressure on ports to decarbonize.
  • PortMiami is the largest cruise ship port in the world with 1,700 cruise ship visits a year and each boat needs as much as 10 megawatts of power.
  • PortMiami now plans to develop the nation’s first net-zero carbon emission cargo supply chain.

In January 2024, the world’s largest cruise ship, Icon of the Seas, will reach her new home in Miami, Florida. At 1,200 feet long and a quarter of a million tons in weight, with seven swimming pools, 10 decks, 40 bars and restaurants and 9,950 people on board, she is the symbol of an industry that has resurrected itself since the COVID-19 pandemic.

Cruise-ship holidays are now the fastest-growing sector in the travel industry and 2023 looks set to break 2019’s record of 30 million passengers. PortMiami, the world’s largest cruise ship terminal, welcomed 6.8 million of those passengers in 2019 and now the near-shoring of supply chains is likely to boost its cargo traffic too. The port, which contributes $43 billion to the local economy, is determined to capitalize on these growth opportunities in a sustainable way.


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Cold ironing – a hot ticket for ports to cut emissions and pollution

Commercial shipping is an industry under heavy pressure to decarbonize. Big commercial vessels – whether carrying containers or holidaymakers – pump out over one billion tonnes of greenhouse gases a year, accounting for 2.9% of global emissions. The viscous bunker fuel they burn is among the filthiest of all fossil fuels. Each day a cruise ship is at sea, it emits more toxic sulphuric gas than 13 million cars and more soot than a million cars, according to US government data cited by Friends of the Earth, which issues an annual Cruise Ship Report Card.

Even while cruise ships rest up in port – which can be half their working lives – they have to power themselves by idling auxiliary engines and burning more bunker fuel. This isn’t just bad for the environment – the particulates, phosphorus, sulphur and nitrogen oxides they emit are a serious health hazard for local residents too.

PortMiami’s answer is simple: shore-side electricity or, in maritime jargon, 'cold ironing.' But like a lot of simple ideas, to make cold ironing a reality is deeply complex. Miami sees 1,700 cruise ship visits a year and each boat needs as much as 10 megawatts of power while in port. Equipping an older ship with a shore-power connection costs up to $2 million, while installing the infrastructure in port can cost several million more.

Some shipowners have already taken the initiative. Norwegian Cruise Line Holdings, for example, is aiming to equip 70% of its fleet with plug-in, shore-power technology by 2025. According to the Cruise Lines International Association (CLIA), two-thirds of the global cruise fleet will be equipped with shore-side power capability within five years.

California is an early adopter of cold ironing. Since 2014, a state-level shore power regulation has required cargo fleets calling at all California’s ports to shut down their auxiliary engines and plug into shore power. Initially, 50% of a fleet’s visits had to do this, but by 2020 this had risen to 80%. The challenge facing cruise ships is that currently just 14 passenger ports worldwide have berths offering ship-to-shore power.

PortMiami plans to implement the largest shore-power project on the eastern seaboard of the US, focused initially on cruise ships. The port is rehabilitating a downtown co-generation facility that hasn’t been in use for over a decade. Port and county will share the electricity generated between them. “We need to add capacity anyway, so we want to do it in a way that will achieve our net-zero goals,” says Andrew Hecker, assistant port director and chief financial officer. “The act of expanding will drive decarbonization,” he adds.

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'Friend-shoring' can boost volumes and stimulate decarbonization

The next stage in PortMiami’s plan is a five-year $700-800 million project to build out the infrastructure to decarbonize the port’s cargo handling and distribution. The port sees 1,100 cargo ship visits a year, but Hecker sees this number rising considerably. Factors include the near-shoring or 'friend-shoring' of supply chains – a reorientation of shipping routes away from the east-west axis between Russia, China and the Far East, towards a north-south axis between North and South America. Hecker points to the huge opportunity offered by Mexico, for example: “97% of all trade with Mexico comes in by truck. If we moved only 10% of that via sea, it would increase our volumes by 20-30%,” he says.

To capture this opportunity, PortMiami plans to develop the nation’s first net-zero carbon emission cargo supply chain. This will deliver goods from ship to shore and on to distribution centres using decarbonized power and equipment. The centrepiece of this plan is a custom-built 200-acre inland port and export consolidation centre, connected to the seaport by newly expanded railways that replace polluting diesel trucks. To clean up this supply chain, the port will convert all cargo handling equipment – such as tug boats, gantry cranes, locomotives, yard tractors and semi-trucks – to electricity.

The bottleneck is not only funding, but also the capacity of Florida’s utilities to deliver sufficient power. “We’re building to the capacity that the utilities say they can bring on board,” says Hecker. And shore power’s the easy part. According to Justin Jones, senior vice president at Canadian construction company AtkinsRéalis, “Once you start electrifying all the equipment, the cranes, the trucks and so on, the power drain on the grid is huge.” MiamiPort is working closely with Florida Power & Light (FPL) on increasing its renewable capacity. “Can FPL run out and build wind turbine farms overnight?” asks Jones rhetorically. “No, but FPL knows it has a client that is going to be increasing demand and that’s how you get this financed.”

The inland port will enable Miami to handle 50% more container volume, while sticking to the county’s climate target to slash emissions by 50% by 2030 on the way to net zero by 2050. Miami Dade County Mayor, Daniella Levine Cava, emphasizes how sustainability and economic expansion must progress hand-in-hand. She says: “In Miami-Dade, we know that our environment is central to our health and our economy. We are also ground zero for sea level rise and climate change, so we have a unique role to play in leading the way for coastal communities in the US and around the world.”

The benefits of decarbonization will extend far beyond the cruise ship industry. Antwerp, recognized by the UN as a pioneer of port sustainability, has found that greening its port has helped the wider area with its low-carbon transition. “It gives oxygen to new companies as well as to existing companies to diversify, add new revenues and services,” says Tom Monballiu of the Antwerp Port Authority. “Miami is a very important cruise port. If they can manage to green their maritime industry, it will immediately have a positive impact on the city itself, improve air quality and create new jobs.”

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