Abstract
This review covers the tidal energy resource in the UK, and also considers grid connection issues, policy related to tidal energy development and issues associated with sea level rise and coastline types.
Tides are caused by the gravitational attraction of the moon and the sun acting upon the oceans of the rotating earth. The rise and fall of the tides gives rise to horizontal water movements, known as tidal currents (or streams), and vertical water movements, known as tidal range. Both tidal range and tidal currents can be used to generate energy, typically in the form of electricity.
In the UK high and low tides occur approximately twice daily, and the time of high water advances by approximately 50 minutes per day. The height of the tides change on a worldwide 14 day cycle due to the degree of alignment between the moon and the sun. This gives rise to spring, and seven days later, neap tides. The tides are also affected by a half-year cycle, due to the inclination of the moon’s orbit to that of the earth, giving rise to the largest spring tides around the time of the March and September equinoxes, and the smallest spring tides approximately coincident with the summer and spring solstices.