Tidal stream energy

Tidal stream devices harness the power of the natural ebb and flow of coastal waters caused by the earth’s gravitational relationship with the moon and sun.

The UK, as an island nation, has tremendous tidal resource. Its practical resource (tidal power that could be economically captured) is the equivalent of 11% of its current electricity demand. Tidal stream energy has already provided over 45GWh of clean, predictable electricity.

This energy can be harnessed through a variety of different technologies. These include (but are not limited to) turbines that are attached to the seabed, turbines that are attached to a floating device and kites tethered to the seabed.

As water is 820 times denser than air these devices tend to be smaller and move more slowly than wind turbines. This is beneficial in providing efficient energy yield and avoiding disruption to the natural environment.

Tidal stream devices generate electricity regardless of whether the sun is shining, or the wind is blowing, across all seasons. It is estimated that the UK has around 50% of Europe’s tidal energy resource.

The timing of high and low tides around varies at different locations around the UK. This means that as the UK installs tidal stream devices at these different points, tidal stream devices will be able to generate electricity all year round at all times of the day.

Tidal stream energy is therefore an entirely predictable and renewable source of firm power energy. As the UK becomes increasingly dependent on less predictable sources of energy, tidal stream can displace a reliance on imported gas, technologies, and other solutions.

Research by Imperial College shows that tidal stream has the potential to reduce natural gas capacity required by about 40%. As more than half of UK gas is imported tidal stream is poised to play a key role in the UK’s energy security.

In the UK’s latest renewable auction four tidal stream projects were successful and will deliver over 40MW of capacity at £178.5MWh. This is the first revenue support that the sector has received, and the industry responded by coming in 15% below the Administrative Strike Price.

Tidal stream is forecast to be significantly cheaper than new nuclear at 1GW of deployment, falling to below £80MWh, and to below £50MWh by 2050. The cost reduction will be realised through innovation, economies of scale and volume. Projects are being delivered with over 80% UK content, and the industry is poised to contribute £17bn to the UK economy by 2050.