The "service power packages" upgrades will include ongoing installations throughout 2023 on ships belonging to the company’s nine brands – Carnival Cruise Line, Princess Cruises, Holland America Line, Seabourn, P&O Australia, Costa Cruises, Aida Cruises, P&O Cruises and Cunard.

Developed over the last six years and tailored to each vessel, upgrades to save energy include investments in variable speed drives and on-demand automation and controls, cooling enhancements, energy-saving LED lighting and more efficient heating and ventilation systems.

Carnival estimates the programme will deliver an average of 5-10% fuel savings per ship and is expected to reduce fleet-wide greenhouse gas emissions by more than 500,000 metric tons each year.

The upgrades will also result in around $150 million in fuel cost savings per year.

Carnival’s chief maritime officer Bill Burke said: “Based on our improved fleet composition, including adding six industry-leading LNG-powered ships, and our previous investments to increase efficiency and reduce emissions, our absolute carbon emissions peaked in 2011 despite significant capacity growth over the past decade.”

“These tailored service power packages further build on those efforts as part of our comprehensive approach to sustainability.”

The fleet-wide enhancements are part of Carnival’s energy efficiency investment programme. The company has committed to reducing carbon emission intensity by 20% from its 2019 baseline by 2030, supporting its efforts to achieve net carbon-neutral ship operations by 2050.