The UK has the second-highest tidal range in the world and there are estimates that around 50% of Europe’s tidal energy resources lie in UK waters.
The global demand for energy is showing no sign of slowing down. Despite lockdowns and huge supply chain disruptions, the ocean energy sector hit several milestones last year. Growing awareness of our climate crisis has resulted in national and international agreements around clean and renewable energy generation that is prompting science, governments, and the energy industry as a whole to cast their nets towards the oceans.
So, how does it work?
Surface water stores heat we can harness to generate electricity, researchers have even worked out ways to take advantage of the natural difference in pressure between saltwater and freshwater (known as “the salinity gradient”) to generate electricity.
Research suggests that Ocean Energy could provide at least 15% of the UK’s annual electricity and similarly, the UK currently has the second-highest tidal range in the world and there are estimates that around 50% of Europe’s tidal energy resources lie in UK waters.
The UK wave energy sector has accumulated considerable experience, expertise and knowledge from the development and deployment of various prototypes and has a strong community of academics and industry. Plus, there are estimates of up to 8,100 new jobs in wave energy by 2040.
What are the different types and how does it work?
Wave energy – whereby converters capture the energy contained in ocean waves and use it to generate electricity. Converters include oscillating water columns that trap air pockets to drive a turbine; oscillating body converters that use wave motion; and overtopping converters that make use of height differences.
Tidal energy – produced either by tidal-range technologies using a barrage (a dam or other barrier) to harvest power between high and low tide; tidal-current or tidal-stream technologies; or hybrid applications.
Salinity gradient energy – arising from differing salt concentrations, occurs when a river empties into an ocean. Demonstration projects use “pressure retarded osmosis”, with fresh water flowing through a membrane to increase the pressure in a tank of saltwater; and “reverse electrodialysis” with ions of salt passing through alternating tanks of salt- and freshwater.
Ocean thermal energy conversion – which generates power from the temperature difference between warm surface seawater and cold seawater at 800–1,000 metres depth.
