Case Study: Tidal Stream Generators

As we move forward from the announcements of Allocation Round 5 (AR5), we welcome the new additions of emerging technologies such as tidal stream generators. However, as the world grapples with the urgent need to reduce our greenhouse gas emissions and transition to a net zero energy system, we need all the tools available in our toolbox. With the development of innovative sustainable technologies, it offers unique benefits that can supplement existing generation and deliver net zero.In this article, we will be exploring the functions and benefits of tidal stream generators in the production of low carbon energy.

What is tidal stream generation?

Tidal stream generators are devices designed to harness the kinetic energy of the ocean tides. They operate similarly to wind turbines, but instead of wind, they utilise the powerful and predictable movement of the tides to generate electricity.

When tidal currents flow past submerged turbine blades, the flow of water causes the blades to rotate, just like the wind turns the blades of a wind turbine.

The benefits of tidal stream generators

Tidal energy stands as a predictable and dependable clean energy source, offering the potential to support the UK's baseload energy generation. The UK is in a unique position in its relationship with tidal stream generators, the multiple coastal locations of the UK make the country a prime location to harness the power of tidal energy. Moreover, the shipbuilding heritage of the country allows for the UK supply chain to organically transition into tidal technology.

Like wind turbines, these generators create a renewable energy source that is derived from a natural phenomenon.  Unlike wind, the natural phenomenon of the tides occurs in a pattern predictable as clockwork. This makes tidal stream generation a reliable and consistent source of energy, allowing for accurate energy production forecasting and stability.

Moreover, these generators have environmental impacts and are largely able to leave the marine sea life undisturbed. Tidal currents are over 800 times denser than wind, which means they carry a significant amount of kinetic energy. As a result, tidal stream generators can capture a substantial amount of energy from sweeping a relatively smaller area.

Our work with tidal stream generators

At the LCCC, we are the counterparty of several CfDs that support tidal stream generators. Allocation Round 4 awarded 4 CfDs to 3 separate generators with a total capacity of 40.8MW. The recent AR5 went further, awarding 11 CfDs to 6 separate generators (including 3 newcomers), with a total capacity of 53MW. Because of the investor confidence that the CfD has given tidal stream technology, it has allowed the UK to be a leading pioneer of this method of energy generation.

In September 2023, our team that consisted of James King, Paul Kiddle, Claire Daniels, and Fattaur Rahman visited several tidal stream generator sites.

Orbital Marine Power is one of the generators we work with, with 4 CfDs across the two allocation rounds with a total capacity of 14.4MW at the fall of Warness site, operated by the European Marine Energy Centre (EMEC) in Orkney.

During the visit to Orkney, the team received a comprehensive health and safety briefing at the Orbital offices before embarking on a voyage to their Orbital O2 generating platform. Inside the platform, the design focused on ease of maintenance and maximising generation time, with the main platform anchored to the seabed. The design enables the wings to also be brought to the water surface to allow for ease of access for maintenance.

Built with 80% of its materials sourced from the UK, the O2 is an example of the organic relationship this technology has with the UK, and the numerous opportunities that it can offer local industry. With the newfound AR5 contracts, Orbital is channelling its efforts into design enhancements and scaling up their supply chain to meet increased capacity.

Another generator visited in September was Magallanes Renovables, awarded 1 AR4 CfD, and secured two additional AR5 CfDs combining to a total capacity of 10.5MW. Whilst Magallanes’ AR4 CfD is in North Wales, the technology is refined at EMEC. Their current platform (ATIR) boasts a surface appearance resembling a ship but conceals a complex underwater system.

Simplicity and reliability are the cornerstones of their design, aiming to minimise moving parts and external maintenance requirements. Innovative solutions were being tested during the visit, such as testing methods to tilt the platform for easier maintenance. The team at Magallanes showcased their platform, ATIR, and provided valuable insights into their approach to tidal energy generation.

The visits were educational about the potential of tidal stream generators as well as the challenges that remain for these technologies to prove their worth. The consensus among the tidal generators we met emphasised the need for sustained support under future CfD rounds, ideally with multiyear budget visibility of future ring-fenced support for tidal Stream Energy, to enable technology and project development, and garner further private investments.

Conclusion

To conclude, tidal stream generators represent a promising avenue for producing predictable, low carbon energy. Their ability to harness the reliable and predictable power of ocean tides offers numerous benefits, including clean and renewable energy production, minimal environmental impact, and grid stability. Still, our site visit has also showed that there are still challenges around the cost and maintenance of such technology.

Tidal energy has the potential to play a significant role in delivering net zero, as we continue to seek sustainable solutions to meet our energy needs. With the CfD mechanism, such technologies can continue to evolve and become more refined.