Royal Caribbean International’s new cruise ship Star of the Seas marks a major step forward in the energy performance of the company’s fleet. According to Nick Rose, Vice President of Environmental Programs, the vessel is about 24% more efficient than the previous generation Oasis-class ships.
Streamlined hull, LNG and advanced heat recovery
This significant efficiency gain is the result of several design and technology choices, including:
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a streamlined hull form that reduces hydrodynamic resistance,
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the use of liquefied natural gas (LNG) as the primary fuel,
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advanced waste-heat recovery systems, which Rose notes are even more capable than those on Icon of the Seas, delivered in 2024.
Waste-to-energy and smart onboard energy systems
Star of the Seas also features cutting-edge waste management and energy technologies that convert waste into usable energy, including:
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microwave pyrolysis,
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micro automated gasification.
In addition, the vessel is equipped with a low-noise energy management system that leverages machine learning to automatically adjust lighting, heating, ventilation and air conditioning based on passenger presence and real-time demand.
LNG advantages and cold-energy recovery
Rose highlighted the advantages of LNG in terms of energy density, while acknowledging that it requires more storage space and must be kept at around –126°C.
This ultra-low temperature creates an additional opportunity: both Star of the Seas and Icon of the Seas can recover energy from both heat and cold, further improving overall system efficiency.
Looking ahead: more flexibility for alternative fuels
Royal Caribbean is already planning further improvements for future ships, including the Legend of the Seas, which is being built by Meyer Turku for delivery in 2026.
A key focus will be greater fuel flexibility, enabling the use of alternative fuels such as methanol, similar to what is being implemented on Celebrity Xcel.
While year-on-year efficiency gains between individual sister ships may appear modest, Rose stressed that the cumulative improvements across an entire class are substantial.
AI-powered optimisation: the MIAP program
The company also deploys artificial intelligence through its MIAP (Machine Learning and AI Program) to optimise key onboard systems, including:
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power generation and distribution,
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HVAC (heating, ventilation and air conditioning),
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water production and distribution.
Initially focused on data collection and analysis, MIAP now supports predictive maintenance and real-time optimisation — for example, identifying pumps that are running unnecessarily and adjusting operation accordingly.
AI-driven analytics is applied both on newbuilds and on retrofitted ships, ensuring continuous improvement in efficiency across the fleet.
Water production and sustainability in practice
Star of the Seas is a showcase for Royal Caribbean’s sustainability strategy in action. The ship:
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produces 100% of its own water using an advanced reverse osmosis system,
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simultaneously reduces overall water consumption thanks to precise monitoring and control.
By combining innovative technologies, alternative fuels, AI-based optimisation and efficient design, Star of the Seas demonstrates how a major cruise operator can move towards a more sustainable and resource-efficient fleet.
