Project Zero: Rethinking energy use in sustainable yacht design

Overview

Conceived as the world’s first sailing yacht of its type and size to operate free of fossil fuels, it explored how renewable energy generation could be combined with lower onboard demand without compromising comfort, performance, cruising autonomy or aesthetics. To support this required rethinking, all innovations and data are being shared on the opensource platform, Foundation⁰.

Challenge

Designing a large yacht to operate without fossil fuels meant rethinking how energy would be generated, stored, managed and used onboard. Renewable energy still had to meet the yacht’s demands, while battery safety and the effect of new arrangements on the wider vessel also had to be understood.

SY Zero set out to achieve this by generating renewable energy while reducing onboard demand.

Developing an integrated design

The project approached the yacht as a single energy system. More than 60,000 hours of research and development were completed before construction began, with existing vessels used as live testbeds to validate concepts and gather operational data.

The project brought together designers, naval architects and shipbuilders with specialists in batteries, physics, systems engineering, digital technology and computational fluid dynamics. Owners’ representatives and flag administration specialists were also involved. Lloyd’s Register (LR) acted as the classifying body for SY Zero, supporting the yacht’s development while maintaining its supervisory role.

This approach enabled ongoing engagement with the novel technologies and integrated systems being developed for the yacht. Vripack led the exterior and interior design, thermodynamic modelling and energy concepts. Vitters Shipyard contributed construction and prototyping expertise, while Dykstra Naval Architects supported naval architecture and hydrogeneration.

Together, the team could assess the yacht’s energy system within a single design model.

Newerable generation and reducing demand

SY Zero sought to capture energy from the sun, wind and water. The proposed solutions included solar photovoltaic generation, solar heat collection, heat recovery from systems and hydrogeneration while sailing through reversible, pod-based propulsion systems. The hull, appendages and sail plan were also optimised to improve generation efficiency.

LR’s certification approach reflected the yacht’s reliance on sailing propulsion. LR certified the rig as the vessel’s primary propulsion system, an unusual arrangement as nearly all sailing vessels have their auxiliary engines certified in that role.

Reducing onboard demand was equally important. Analysis found that heating and cooling accounted for approximately 47% of total demand, prompting detailed investigation into ways to reduce heating, ventilation and air conditioning loads.

The measures explored included vacuum glazing, cork deck insulation and heat-reflective coatings, together with natural ventilation, passive and adiabatic cooling via the masts, thermal loops, adsorption chillers and waste heat recovery. Reduced propulsion drag and water conservation were also explored.

Energy storage, modelling and operational data

Battery systems were designed around operating scenarios and autonomy requirements rather than installed capacity alone. The project considered energy density, weight distribution and stability, alongside cooling, ventilation and measures to mitigate thermal runaway. It also explored thermal storage through heat and cold buffers and phase-change materials.

During the design phase, an extensive thermodynamic model simulated the yacht’s thermal behaviour using its construction materials, accommodation layouts, system loads and environmental conditions. By creating a virtual representation of energy flows, the model allowed the team to quantify consumption and refine concepts before physical installation.

Digital tools were intended to extend this approach into operation. Real-time monitoring, data logging and visualisation would show how energy was produced and used, while weather routing and voyage energy forecasting tools were designed to increase the crew’s awareness of energy use.

LR certified the rig as the vessel’s primary propulsion system. This was highly unusual, as nearly all sailing vessels have their auxiliary engines certified as the primary propulsion system.

Wider learning

SY Zero is also intended to support continuing research and share openly what is learned. For LR, acting as the classifying body provides direct engagement with the novel technologies and integrated systems being developed for the yacht. That experience could help shape the classification of increasingly complex low-carbon vessel designs.