Tidal power, despite its predictable energy generation, struggles with high costs and slow development, hindering its widespread adoption as a renewable energy source. The UK, a leader in tidal stream development with about 10 MW currently installed, has seen projects cancelled due to financial viability issues. For instance, three tidal stream projects by Nova Innovatio (Seastar 1, Oceanstar 1, and Oceanstar 5), representing 6 MW, had their subsidy contracts terminated in May 2026. These projects, awarded contracts at $218/MWh, saw their costs inflate to $323/MWh, making them uneconomical. The cancellation was a significant setback, as Nova Innovation's SEASTAR project alone would have deployed 16 turbines, demonstrating array-scale cost reductions.
The high Levelised Cost of Energy (LCOE) for tidal stream, estimated at $330/MWh by ORE Catapult (down from $383/MWh in 2018), remains a major barrier. While costs could potentially fall to $99/MWh by 2035 and below $64/MWh with significant deployment, reaching the necessary scale of 1 GW for substantial cost reduction is decades away at current build rates. The UK government's Contracts for Difference (CfD) scheme provides critical support, but the allocated funds, such as the $12.7 million ringfence in AR6, are often insufficient to drive rapid expansion and attract large-scale private investment.
Continued government subsidies are crucial for the tidal industry, similar to the early stages of wind and solar power. Without such mechanisms, projects would not be economically viable. Experts suggest that a "sweet spot" of over 30 MW projects is needed to attract significant investors. The MeyGen project in the Pentland Firth, currently powering about 6,000 homes, exemplifies the potential, with plans to scale up to 398 MW. However, challenges include reducing supply chain costs, technological advancements for reliability, and navigating environmental impacts.
The sector faces four main pressure points: site development, financing structures, innovation support, and supply-chain capacity. A 2025 University of Edinburgh study suggests that deploying 6.2 GW of tidal stream by 2050 could generate over $63.5 billion in gross value added and sustain 80,000 jobs in the UK. Furthermore, tidal generation could reduce wholesale energy prices by around $153 million annually between 2037 and 2060. However, bridging the gap between CfD awards and bank-funded construction contracts remains an unresolved financial architecture challenge, as demonstrated by Nova Innovation's cancelled projects.
Overall, while tidal power offers predictable and consistent energy, its journey to commercial viability is hampered by the substantial investment required to bring down costs and scale up deployment. The industry requires sustained government support, targeted investment, and technological advancements to move beyond demonstration projects and attract the large-scale private capital needed for widespread adoption.
