Wind turbines altered to function underwater have now set industry records for generating nonstop power.
The AR1500 tidal energy turbine. Source: Lockheed Martin

“A very significant milestone.” That’s how Rémi Gruet, CEO Ocean Energy Europe, describes the latest news about the MeyGen project to generate electricity from oceanic tides.
For over six years, four modified wind turbines, sunk in 130 feet of water off Scotland’s coast, have produced power for 7,000 homes, with no maintenance required. That lack of maintenance is key to the commercial viability of sourcing energy from water.
Creating durable devices that can withstand the harsh sea environment has been a challenge for innovators and investors looking to develop marine energy – power generated from tides, currents, waves, or temperature changes. Regularly removing underwater devices for maintenance has previously made tidal energy cost prohibitive. Now, MeyGen, a six megawatt-per-hour project, owned by SAE Renewables and built in concert with Swedish firm SKF, has solved the problem. The project has recently reported that their sturdy underwater turbines have been working for over six years without having to be removed for repairs.
The implications are huge. Marine energy is the world’s largest untapped renewable energy resource, according to the National Renewable Energy Laboratory. Oceans cover more than 70% of the planet’s surface and hold about 97% of the Earth’s water. Cracking the code on technology that can convert this vast resource into electricity holds the potential for a revolution in delivering the power of the future.
The MeyGen project was ambitiously designed for success on a big scale.
The largest planned tidal stream project of its kind in the world, it was carefully sited in some of the fastest flowing waters in the U.K. Located in the Pentland Firth, between the northeast tip of Scotland and the island of Stroma, the turbines sit in a channel that accelerates millions of tons of water flowing between the North Sea and the Atlantic Ocean, twice daily, because of its strong tidal currents, among the fastest in the world. A speed of over 18 miles per hour has been reported.
When the force of tides is amplified by overfalls and tidal races and whipped up by gale-force winds, extremely violent sea conditions can occur. Even average oceanic waves reach 6-10 feet and spring tides flow at 9 miles per hour. These waves and tidal flows generate significant power that innovators and investors in renewable energy have had their eye on for some time.
The high flows, medium water depths, and proximity to the mainland made the Pentland Firth a prime location for development, says SAE. The current six megawatt, four-turbine rig has been sending electricity to the Scottish grid for over eight years. MayGen intends to add 20 more turbines in 2030, after needed upgrades to the electrical grid are finished. The site could eventually consist of 400 turbines more powerful than those being used today, generating up to 398MW and powering, theoretically, 300,000 homes. (1GW can power 750,000 homes, assuming a consistent output.)








