Current tidal power technologies and their suitability for applications in coastal and marine areas

TLDR

Research is actively quantifying tidal energy resources and developing efficient devices, yet the feasibility of small‑scale, local tidal power in shallow near‑shore sites remains largely unexplored, despite its potential to supply sustainable electricity to coastal communities with lower installation and capital costs. This article reviews tidal barrages, lagoons, turbines, oscillating hydrofoils, and tidal kites to assess their suitability for small‑scale electricity generation in shallow coastal waters at the design stage. The review evaluates each concept’s power density, scalability, durability, maintainability, economic potential, and environmental impacts. The analysis indicates that tidal kites and range devices are unsuitable for shallow, small‑scale applications, while cross‑flow turbines emerge as the most appropriate technology due to high power density and depth‑independent size, with oscillating hydrofoils also viable if efficiency levels are comparable.

Abstract

A considerable body of research is currently being performed to quantify available tidal energy resources and to develop efficient devices with which to harness them. This work is naturally focussed on maximising power generation from the most promising sites, and a review of the literature suggests that the potential for smaller scale, local tidal power generation from shallow near-shore sites has not yet been investigated. If such generation is feasible, it could have the potential to provide sustainable electricity for coastal homes and communities as part of a distributed generation strategy, and would benefit from easier installation and maintenance, lower cabling and infrastructure requirements and reduced capital costs when compared with larger scale projects. This article reviews tidal barrages and lagoons, tidal turbines, oscillating hydrofoils and tidal kites to assess their suitability for smaller scale electricity generation in the shallower waters of coastal areas at the design stage. This is achieved by discussing the power density, scalability, durability, maintainability, economic potential and environmental impacts of each concept. The discussion suggests that tidal kites and range devices are not well suited toward small-scale shallow water applications due to depth and size requirements, respectively. Cross-flow turbines appear to be the most suitable technology, as they have high power densities and a maximum size that is not constrained by water depth. Oscillating hydrofoils would also be appropriate, provided comparable levels of efficiency can be achieved.