The inside story on Tidal Stream Energy

By Simon Cheeseman, Sector Lead, Wave & Tidal Energy, ORE Catapult

The Potential

Wind power technology has advanced at an impressive rate over recent years. However, to meet 2050 net zero targets it is vital that the potential offered by tidal stream energy is also fully exploited. Around the coast of the UK we have access to outstanding tidal energy resources. For example, Scotland already leads Europe in the installation of tidal power. It has also been estimated that the tidal resources in the Channel could be used to power more than three million homes.

Tidal stream generators draw energy from water currents in a similar way that wind turbines use air currents. Because of the higher density of water compared to air, tidal stream turbines can generate significant power in relatively slow moving tides. In fast-flowing tides, a tidal turbine can generate four times as much energy per rotation as a wind turbine.

Unlike the wind, the tides are constantly in motion, caused by the gravitational pull of the moon. So they are an exceptionally reliable and predictable energy source. This enables operators to calculate with a high degree of accuracy the power output that will be delivered by a specific turbine.

The Energy Technologies Institute has estimated that tidal energy is capable of supplying 20-100TWh of the 350TWh of the UK’s annual electricity demand. The potential impact of the tidal industry on UK GDP is estimated to be in the range of £1.4 to 4.3 billion.

The cost of energy from tidal stream arrays can compete with other low-carbon sources. The sector has transitioned in recent years from small-scale prototype devices, through to full-scale demonstration and early commercial arrays are now in development. The UK leads the rest of the world in the development of tidal devices, so when we need to kick start the economy and rebuild an indigenous manufacturing capability, this could become an important driver for our economy.

The Challenges

The next key step in the evolution of tidal stream energy will be to make advances in the installation, operation, and ongoing maintenance of tidal stream devices, and provide the scale that encourages the supply chain to invest in research and development to drive down costs.

This next phase has been aptly described as “learning by doing.” Developers need to get thorough experience of installing and operating the devices. Work needs to be done on the standardisation of components. Further innovation will be required to solve some of the technical issues. A new supply chain, pulling through proven technology from other sectors, needs to be created to service this sector. 

All this is against a background where tidal energy devices have to be installed in challenging sea conditions, which throws up a further set of problems and risks for businesses.

They key goal over the next few years must be to prove that costs can be driven down to a level where tidal stream energy is conclusively shown to be economically viable and competitive in the long-term. This, in turn, will unlock the large scale capital investment that will be needed for this industry to really take off.

The TIGER Project

This project represents a massive opportunity to make crucial progress in addressing the challenges detailed above.

TIGER stands for Tidal Stream Industry Energiser Project. This is an ambitious €46.8m UK/French collaborative project, of which €28m (69%) comes from the European Regional Development Fund via the Interreg France (Channel) England Programme. This is the largest ever Interreg project, recognising the enormous potential of the tidal resource in the Channel region, and will prove to be game-changing for the European tidal stream energy sector.

The TIGER project aims to drive the growth of tidal stream energy by installing up to 8MW of new tidal capacity at sites in and around the Channel region, thus driving innovation and the development of new products and services.  TIGER will make a stronger, more cost-effective case to utilise this tidal energy capacity and justify the need for tidal stream to become part of the energy mix in the UK and France. The project will do so through collaboration between turbine developers, sharing data and lessons on resolving generic problems and identifying opportunities to  harness economies of scale via volume manufacturing and multi-device deployment.

TIGER, led by the UK’s Offshore Renewable Energy Catapult (a Marine-i partner), brings together leading turbine developers, academics at the forefront of tidal stream energy research, and test centres across the UK and French offshore renewable energy supply chain to work towards validating the commercialisation of marine energy technology. This validation will help to ensure that sustainable and affordable energy plays a key role in our future energy mix as we work towards achieving net-zero by 2050 and beyond.

Businesses Opportunities

For the reasons given above, we could be on the threshold of a period of exceptional growth for tidal stream energy, one which could prove very valuable for innovative marine businesses. As with any new technology, there are still many technical issues waiting to be solved by inventive businesses, possibly working in collaboration with others in the industry. 

Here are examples of some key technical opportunities, as identified in a report by ORE Catapult:

Tidal turbine blades. The manufacturing processes for these are currently very labour intensive, which increases time and cost. Blades also need to be proven for long-term durability in a marine environment in order to provide comfort to developers, investors, and insurers.

Pitch control. The pitch control systems used in wind turbines are not suitable for tidal turbines, making this a crucial area for development. These systems are critical to power output performance and a major driver of bankability and insurability.

Subsea electrical hubs: These enable connection of 8-12 turbines through a seabed mounted junction box. Grid connection supply and installation costs can currently make up around 20% of project costs, so successfully proving subsea hub technology in situ could have a significant cost saving impact.

Nacelle deployment and recovery. For subsea turbines, vessel costs are a significant component of operating and deployment cost. The development of technology that would allow low-cost, locally available vessels to be used for nacelle deployment and retrieval could significantly cut the levelised cost of energy for tidal stream devices.

How can I get involved?

If this is an area that interests your business, contact the expert team at Marine-i. We will help you use the full potential of Research, Development, and Innovation so that your innovation can get to market more quickly and with a greater chance of commercial success.

You can also register for a series of six free webinars that will explore the supply chain opportunities associated with the TIGER project. The first webinar takes place on 9th July 2020 and will focus on subsea cables and connectors, aiming to integrate cross-sector supply chain capability and innovation into the development of world leading tidal energy projects. For more information about the first webinar, including how to register, visit: https://www.marine-i.co.uk/event/35/tiger-opin-webinar-tidal-supply-chain-opportunities