Tidal Energy: Technology brief

Tides are the result of the interaction of the gravity of the sun, earth, and moon. The rise and fall of the tides – in some cases more than 12 m – creates potential energy. The flows due to flood and ebb currents creates kinetic energy. Both forms of energy can be harvested by tidal energy technologies as renewable energy. Tidal energy technologies are not new: examples were already reported in Roman times and ruins of installations – tidal mills – are found in Europe from around the year 700. Since the 1960s, only five projects have been developedcommercially in the period up to 2012. However, new technologies have advanced considerably over the past few years and there are a number of ongoing full-scale demonstration projects.

This technology brief analyses the process and technology status, potential, future prospects, costs and performance of this key renewable energy system.

The brief forms part of a set by the International Renewable Energy Agency (IRENA) covering four main types of ocean energy technologies: Ocean Thermal, Tidal, Wave and Salinity Gradient energy.

Successive technology briefs have highlighted a wide range of renewable energy solutions. Each brief outlines technical aspects, costs, market potential and barriers, combined with insights for policy makers on how to accelerate the transition to renewables.