A steady hum resonates miles offshore, where a turbine anchored in deep waters off northern Scotland has quietly defied every expectation of wear and tear. Each turn of its blades carries the weight of years spent battling salt and pressure, hinting at a chapter in renewable power that often goes overlooked beneath solar panels and wind farms.
Submerged some forty metres below a stretch of sea infamous for its powerful currents, this grid-scale turbine has cranked out clean electricity without once being yanked from its underwater moorings for unplanned repairs. The achievement has won nods from sceptics and seasoned engineers alike, setting the stage for a tidal industry that investors have long regarded as tantalising yet stubbornly unproven. Now, as bearings and seals enter their seventh year in relentless rotation, a fresh narrative is emerging, one that encourages capital to flow towards a resource as predictable as the moon’s pull.
For decades, tides have promised a future of reliable, carbon-free power, yet the technology needed to tame those forces remained in its infancy. Early trials spluttered and stalled; prototypes required frequent haul-outs for maintenance, driving costs to levels that no balance sheet could reconcile. The Pentland Firth, a narrow channel between Scotland’s mainland and Stroma Island, was chosen not merely for its sweeping views but for the consistency of currents that race at speeds few turbines can withstand. Here, in the Inner Sound, four robust machines deliver a combined six megawatts, enough to illuminate some 7,000 homes year after year, yet it was the unseen durability that truly captured attention.
Behind the scenes, a collaboration between an energy developer and an engineering specialist forged components that shrug off corrosion and fatigue. Bearings designed to endure constant friction have ticked over millions of revolutions, supported by seals that keep abrasive particles at bay. This precision engineering, refined through iterative testing, addresses a fundamental investor anxiety: recurring maintenance costs. The real breakthrough lies not in peak output but in the reassurance that turbines can remain submerged indefinitely, turning tides into a dependable revenue stream rather than a gamble.
As the turbine’s record-breaking run wound past six and a half years, industry bodies hailed the milestone as the clearest indicator yet that tidal energy might finally graduate from demonstration projects to mainstream infrastructure. Grid operators, once cautious about intermittency, have begun to factor tidal flows into supply forecasts, appreciating the predictability that solar and wind cannot match. Where daylight wanes and winds shift, the ocean’s rhythm remains a constant. For portfolios seeking diversification, an allocation to tidal arrays could temper exposure to the familiar ebbs and flows of other renewables.
Looking ahead, plans are already under way to scale the site from a quartet of machines to dozens by the end of the decade. Upgrades to transmission lines will remove existing bottlenecks, while phased investment could bring capacity as high as 130 turbines, each more powerful than its predecessor. Such expansion, once granted the necessary licences, would transform a single demonstration zone into one of the world’s largest tidal farms. Investors drawn by the longevity of components can also anticipate economies of scale in installation and maintenance, further compressing the levelised cost of energy.
Outside Scotland, similar projects are stirring interest in coastal regions with strong tidal currents. From Canadian straits to Asian archipelagos, the template is clear: secure durable equipment, prove continuous operation and then replicate. While environmental and regulatory hurdles persist, the weight of evidence now favours an optimistic outlook. As one executive put it, the challenge is no longer about whether turbines can survive underwater but how swiftly operators can deploy them at scale.
Today’s milestone offers more than a pat on the back for engineers; it represents a tangible signal to capital markets. A technology once deemed niche and experimental is showing the raw endurance that underpins long-term returns. For investors accustomed to watching blades spin above ground, the silent revolution unfolding beneath the waves carries both novelty and assurance. It’s a reminder that sometimes the most compelling opportunities lie not in the loudest headlines, but in the persistent rhythms hidden beneath the surface.
SAE Renewables Limited (LON:SAE) was founded in 2005 as a supplier of tidal stream turbines, SAE quickly grew to include development of tidal stream projects and is the majority owner of MeyGen, the world’s largest tidal stream energy project. a hub for clean energy storage, SAE exemplifies innovative reuse of industrial sites for modern needs.
