Powering the Future: Marine Renewable Energy

The ocean is not just our playground — it’s our powerhouse.
As humanity faces down the dual challenge of increasing energy demand and accelerating climate change, a new frontier is rapidly emerging off our coasts and beneath our waves: marine renewable energy.

From towering offshore wind turbines to the gentle pulse of ocean swells, the ocean offers an abundant, largely untapped source of clean power. In this blog, I will explore the leading marine renewable technologies, the breakthroughs pushing them forward, and how they fit into the energy systems of tomorrow.

Offshore Wind:

Fixed Foundations and

Floating Frontiers

Fixed-Bottom Offshore Wind

Already well-established in Europe and growing fast in the U.S., fixed-bottom offshore wind involves anchoring turbines to the seafloor in relatively shallow waters (typically less than 60 meters). These installations benefit from strong, consistent coastal winds and proximity to major population centers. Countries like the UK, Denmark, and the Netherlands have turned fixed offshore wind into a cornerstone of their national energy strategies.

Technological Gains

• Larger rotors and higher-capacity turbines (now exceeding 15 MW) mean more power per structure.
• Digital twin technology and remote sensing improve performance monitoring and reduce maintenance costs.

Challenges

• Limited to shallow waters.
• Requires extensive marine engineering and environmental permitting.

Floating Offshore Wind

Of the 139 million square miles of ocean covering the Earth, only a small portion has the hallow seafloor profile required for fixed bottom installations.  The alternative depends on installation of floating offshore wind generators — the new deepwater frontier. These floating systems, positioned in water depths over 60 meters in depth, are appearing on coastlines like California, Japan, and the eastern U.S.

How to Float a Wind Farm?

• A number of installation innovations have been deployed to support a floating wind generator, including: tension-leg platforms, semi-submersibles, and spar buoys.
• Connections to the grid are accomplished by advanced mooring systems and dynamic cables..

Why It Matters

Floating wind can drastically expand the global offshore wind resource, bringing zero-carbon electricity to energy-hungry coastal megacities without visible shoreline infrastructure.

Catching the Wave!

Wind energy over the ocean is ultimately transduced into wave energy, opening an additional avenue to energy generation.  Capturing the up-and-down motion of ocean waves through novel buoys is an area of active development.  With ocean covering 70% of Earth, the abundance and predictability of wave activity exceeds that for wind or solar.  The sheer magnitude of mechanical energy available for capture is immense!

How to Catch a Wave?

A number of methods are being devised, test, and piloted, including:

• Point absorbers in which one element is displaced vertically by wave motion;
• Vertical attenuators that flex at the surface; and,
• Oscillating water columns that use air pressure created by wave surges.
• Companies in this space: https://corpowerocean.com, http://www.mocean.energy

Barriers to Scale

There are challenges when it comes to the ocean environment.

• Corrosive saltwater and biofouling demand rugged materials and high maintenance.
• Energy conversion efficiency and survivability in extreme weather remain engineering hurdles.

Nonetheless, innovators are moving forward to deliver a dimension of coast power generation that compliments intermittent renewables like solar and wind.

Tidal Energy: Moon Power!

Ocean tides are created by the gravitational pull of the moon and sun, resulting in a predictable rise and fall in sea level.  The amount of stored energy in these tidal fluctuations is enormous.  How can we capture?

Two Primary Approaches

1. Tidal Stream Generators: Think of them as underwater wind turbines, spun by the kinetic energy of flowing water in tidal currents.
2. Tidal Barrages: These dam-like structures trap water at high tide and release it at low tide, directing the outflow through turbines as seen in traditional hydroelectric generators.

Are there any Examples?

• Scotland’s MeyGen project is one of the world’s largest operational tidal stream arrays.
• South Korea and France have pioneered tidal barrages for decades.
• Companies: https://www.orbitalmarine.com, https://minesto.com

Why It’s Compelling?

• Tides are predictable years in advance, offering a rare kind of renewable stability.
• Tidal projects are ideal for island nations and estuarine environments.

Challenges?

• High upfront infrastructure costs.  The infrastructure for tide capture and direction is considerable.
• Potential ecological impacts on marine life and sediment flow.  Alterations of the coastline to support the installation of tidal systems will impact marine life and sedimentation.

Ocean Thermal Energy Conversion (OTEC): Deep Heat!

OTEC is a unique method that captures energy from the temperature difference between warm surface waters and cold deep seawater — a temperature gradient that is particularly evident in tropical regions.

How It Works

• A working fluid (like ammonia) is vaporized by warm water, spins a turbine, and is then condensed by cold water.
• It’s a closed-loop, steady-state system ideal for 24/7 baseload power.

OTEC’s Promise

• Continuous energy generation in equatorial regions.
• Can be coupled with desalination and aquaculture for multi-use platforms.

Limitations

• Efficiency is low due to small temperature differentials.
• Capital costs for deep seawater pipelines and maintenance are high.

In spite of these challanges, OTEC is intriguing for the synergy it invites with island energy needs in tropical marine locations..

Integration, Storage,

and the Future Grid

Marine renewables don’t exist in a vacuum but are part of an evolving energy ecosystem. Integration of ocean-derived electricity into national and regional grids presents both technical and strategic challenges.

Energy Storage Is Key

Because many marine renewables (especially wave and tidal) don’t match peak demand curves, energy storage technologies are essential.  They include:

• Lithium-ion batteries,
• Flow batteries,
• Hydrogen production via electrolysis,
  are essential to smooth supply.

Hybrid Systems and Co-Location

Forward-thinking projects combine wind, wave, solar, and battery storage into hybrid marine energy farms, maximizing output while reducing infrastructure redundancy. Offshore platforms can also serve multiple roles, combining, for example, aquaculture, maritime observation, and/or even hydrogen production.

The Role of Marine Renewables in a Sustainable Energy Mix

As we build a net-zero future, marine renewables offer a unique trifecta:

• Massive global potential,
• Low visual impact,
• Diverse generation profiles.

They’re not silver bullet but when integrated smartly with land-based renewables, storage, and demand response systems, ocean power becomes a critical enabler of energy resilience and decarbonization.

Final Word: Harnessing the Blue Revolution

At Foil Forward, we champion the acceleration of innovation that’s fast, clean, and ocean-smart. Whether it’s propulsion tech or power systems, the tides of progress are shifting. Marine renewables aren’t just the future — they’re arriving now.

The question isn’t whether we can power the planet from the ocean.

The question is how fast we can start!