Green Shipping and Thermal Storage: How Ships Can Reduce Consumption, Waste, and Emissions with PCM Thermal Batteries

These days, naval energy transition has become a key topic in the maritime sector. The need to reduce environmental impact has pushed many companies toward adopting innovative technologies, turning the concept of green shipping from a simple trend into a true industrial strategy. In this context, PCM thermal batteries are proving to be a strategic solution for recovering energy and optimizing the thermal efficiency of eco-friendly ships.

Ships as Floating Cities: A Problem (and Opportunity) of Heat

Modern eco ships can be compared to floating district heating systems: true floating neighborhoods where, just like in cities, managing thermal energy is a critical challenge.

• During navigation, engines generate large amounts of heat.
• While docked or during loading/unloading, there is a thermal deficit for onboard utilities (e.g., hot water, kitchens, HVAC systems).

This asymmetry leads to waste of ship engine heat, which is often simply dissipated into the atmosphere.

PCM Thermal Storage: The Technology That Turns Waste into a Resource

Phase Change Material (PCM) thermal batteries allow for storing excess thermal energy during navigation and reusing it when needed. This is a well-established technology in other sectors (e.g., industrial, district heating) and is now applicable in the maritime sector with concrete benefits.

How a PCM Battery Works:

1. Heat produced by the engines is directed into a heat exchanger.
2. Energy is transferred to the phase change material, which “charges” during melting.
3. When needed, the PCM solidifies, releasing the stored heat at a controlled temperature.

Benefits for Ship Energy Efficiency

Integrating PCM thermal batteries into the onboard energy system allows for:

• Recovering and reusing waste heat from engines
• Stabilizing the supply temperature
• Improving the ship's energy efficiency
• Reducing fossil fuel consumption
• Facilitating integration with renewable sources

In short, the system can transform any ship into a green ship that not only consumes less but also produces and distributes thermal energy intelligently.

Real Applications: From Onboard Comfort to External Networks

Thermal battery applications onboard are numerous:

• Hot water and space heating for crew and passengers
• Industrial kitchens, laundries, and other thermal utilities
• Preheating fluids for mechanical or technical processes

In this way, stored heat is not wasted but fully reused onboard, ensuring comfort, operational continuity, and more efficient management of the ship's thermal utilities.

Why Is PCM Perfect for Ships?

Phase Change Materials (PCM) are among the most promising technologies for onboard thermal storage. Their characteristics make them particularly suitable for maritime contexts, where space and operational continuity are critical factors.

Main advantages include:

• High energy density in limited space: ideal for engine rooms or small technical areas on ships.
• Stable release temperature: allows for predictable ship thermal energy management, avoiding waste or inefficiencies.
• Modularity and scalability: enable custom installations adaptable to any type of vessel.
• No moving parts: minimizes maintenance and risk of failure, even under challenging operating conditions.

In a sector where reliability, continuity, and space optimization are essential, PCMs offer a concrete, flexible, and sustainable solution.
To learn more, read: PCM Thermal Batteries and District Heating: A Complete Guide

Synergies with Marine Solar and Renewables

PCM thermal batteries don’t operate in isolation. On the contrary, they can be easily integrated with other low-emission technologies, contributing to the creation of a true maritime energy ecosystem.

Here are some of the main possible synergies:

• Onboard photovoltaic systems that generate renewable energy during navigation or port stays.
• Marine cogeneration plants that produce electricity and thermal energy in synergy.

This technological flexibility makes PCM a perfect partner for the progressive electrification of fleets: a tool that, while operating on the thermal side, helps maximize self-sufficiency and sustainability of the onboard energy system.

A New Paradigm for Naval Energy Transition

The introduction of PCM thermal batteries on ships represents a cultural as well as technological shift. Until now, the thermal energy produced by engines has been seen as an unavoidable and wasted by-product.

With thermal storage, however, that heat becomes a valuable resource to strategically leverage for reducing consumption and improving overall energy management.

This technology enables:

• Recovering wasted ship engine heat
• Improving the energy efficiency of ships, especially during port stays or low-activity periods
• Ensuring thermal continuity onboard, even when engines are off or running at reduced capacity

In summary, PCM batteries are not just a technical upgrade: they are a true enabler of naval energy transition, capable of unlocking waste heat and making onboard energy management more efficient.

From Green Shipping to Energy Symbiosis

In short, green shipping is not just about alternative fuels: it also involves smart thermal energy management. The eco-friendly ships of the future will be able to:

• Optimize onboard heat
• Reduce consumption and waste
• Ensure thermal comfort and autonomy onboard, even during long stops or operational changes

In this perspective, PCM thermal batteries are a key piece in designing a sustainable and resilient maritime industry, where every ship becomes a self-sufficient energy system, capable of optimizing and using its resources to the fullest.

At i-TES, we believe that naval energy transition cannot happen without flexible, scalable, and efficient solutions. Want to learn more about how to adapt our thermal batteries to your fleet? Contact us!