Cold Ironing

Cold ironing, also known as Alternative Maritime Power (AMP) or shore-to-ship power (SSP), is the process of providing electrical power to a ship at berth whilst the ships main and auxiliary engines are turned off (Innes & Monios, 2018). Cold ironing means that a ship can continue to receive power for emergency equipment and services such as refrigeration, cooling, heating, and lighting, whilst the ship is loading or unloading cargo.

Shipping accounts for 2.89% of global greenhouse gas emissions (International Maritime Organisation, 2021). More specifically, shipping accounts for approximately 15% of nitrogen oxides (NOx) and 8% of sulphur oxides (SOx) global emissions (Zis et al, 2015). 

Cold ironing reduces air pollution, mitigating emissions such as NOx and SOx from diesel engines by connecting ships to the more environmentally friendly source of electrical power. This can improve air quality locally, but it is important that the electrical power source is a cleaner fuel source or a renewable source (i.e. wind, water, solar) in order for the process of cold ironing to contibute to better air quality nationally and globally (Zis et al, 2015). Cold ironing can also help reduce noise pollution at berth with fewer diesel engines running.

The Port of Aberdeen is investing up to £55 million over 10 years to become the UKs first net zero port by 2040. It was awarded funding in 2023 from the UK Government to design and deliver a large-scale landside and vessel-side shore power system named 'Shore Power in Operation'. By introducing shore power at Aberdeen Harbour, this project aims to cut emissions of particulates, NOx, SOx, and noise by vessels at berth by more than 80% compared with burning marine fuel - saving over 60,000 tonnes of CO2 equivalent over the next 20 years. Shore power at North Harbour would reduce Port of Aberdeen total emissions by 78% - equivalent of 34,000 tonnes of CO2 annually (Port of Aberdeen, 2023b). Construction on the project began in August 2024 and is scheduled to deliver first power in March 2025, with vessels berthed at Albert Quay and Mearns Quay in the North Harbour receiving grid-powered electrictity under the ports renewable energy tarriff (Fig. 1) (Port of Aberdeen, 2024).

In addition to the large-scale shore power initiative, the Port of Aberdeen also plans to install shore power facilties for Serco Northlink's passenger ferries to Orkney and Shetland. This includes 1.7MVA of electrical supply, a new substation, and quayside cable management system. This aims to mitigate over 1300 tonnes of CO2 equivalent annually, and reduce air and noise pollution (Port of Aberdeen, 2023a).