Global OTEC and Makai Ocean Engineering Sign MoU for Heat Exchanger Technology

05 August 2025 — In a positive development for the Ocean Thermal Energy Conversion (OTEC) industry, Global OTEC has signed a Memorandum of Understanding (MoU) with Makai Ocean Engineering (Makai), under which Makai will supply its proprietary Thin Foil Heat Exchanger (TFHX) technology for integration into Global OTEC’s most recent solution, the OTEC Power Module®. This agreement reflects growing momentum toward technology commercialisation, bringing together Global OTEC’s modular and modern approach and Makai’s advanced TFHX to sustainably power the tropical area of the world.

Makai Ocean Engineering, based in Hawaii, has been a leader in OTEC research and development for over four decades, including the design, construction, and operation of one of the only two grid-connected OTEC demonstration plants in the world. This extensive experience highlighted both the technical and economic challenges of scaling OTEC systems, particularly the high capital costs driven by large, titanium heat exchangers. In response, Makai developed the TFHX to reduce system cost without sacrificing performance. The TFHX features compact geometries and corrosion-resistant materials that significantly lower the cost while maintaining high thermal efficiency, durability, and fouling resistance, making it purpose-built for the unique demands of OTEC.

“TFHX was designed to perform in demanding marine environments where reliability, compactness, and durability are key,” said Greg Rocheleau, CEO of Makai Ocean Engineering. “We’re excited about the potential for this technology to support future OTEC deployments and help advance the industry toward commercial viability.”

Using the natural temperature gradient present in the tropical area of the ocean, OTEC can produce clean baseload power 24/7, all year round. Global OTEC’s system is designed to make this process more modular and cost-effective, scaling in increments of up to 500 kW per OTEC Power Module®. Achieving these goals requires compact, corrosion-resistant thermal components that balance performance with material and manufacturing costs; a key consideration in component selection.

By sourcing advanced components from long-standing leaders in OTEC and marine engineering, Global OTEC aims to accelerate the commercialisation of OTEC technology on a global scale. “This agreement brings together decades of innovation in ocean thermal technology with a modern, modular vision for deployment. Our goal is to create a scalable path to offshore OTEC, and integrating proven technologies like the TFHX™ strengthens that effort”, detailed Dan Grech, Founder and CEO of Global OTEC.

The OTEC Power Module®

OTEC Power Modules® mounted on a barge for uncrewed operations

With a modular approach, the OTEC Power Module® is engineered to deliver scalable, clean baseload energy to offshore platforms and tropical nations. This is the world’s first modularised, offshore OTEC system.

Key features:

• 500kW capacity per module, scalable to 1–50MW
• Standardised and prefabricated for cost-effective deployment
• Floatable on offshore platforms, enabling co-location with oil and gas infrastructure, data centres, power-to-X or other coastal demand centres, like ports and marinas
• Optimised through collaborations with leading waste heat recovery manufacturers for next-generation OTEC components

Thin Foil Heat Exchanger (TFHX)

Makai’s TFHX consists of stacked layers of individual proprietary “plates” that together form the heat exchanger core. Manufacturing methods allow for custom non-linear geometries, ultra-compact flow channels, and corrosion-resistant materials at dimension scales from 10 cm to 1 m. TFHX enables high-quality control on the material properties, high smoothness, resistance to fouling, and durability, enabling production of micro-channel heat exchanger performance from small to large-scale thermal loads.

Key features:

• Ultra-compact size
• Conformance to irregular geometries
• Corrosion resistance
• Easy maintenance

About Global OTEC

Global OTEC is a UK-based company set up to accelerate the commercialisation of a floating OTEC technology to develop zero-carbon, baseload, clean energy sources that achieve maximum impact in empowering SIDS, Least Developed Countries (LDCs) and Coastal Nations with energy security whilst helping the Earth reduce greenhouse gas emissions and eventually eliminate total dependence on fossil fuel.

About Makai Ocean Engineering

Makai Ocean Engineering, Inc. is an innovative ocean technology and engineering firm based in Hawaii, providing engineering products and services worldwide since 1973. Makai’s core technical areas include submarine cables, ocean energy and marine pipelines, and subsea technologies such as underwater vehicles, buoys, communications systems and general marine engineering and R&D.