Isle of Wight's Tidal Potential: A Game-Changer for Renewable Energy?

Tidal energy, often overshadowed by its renewable siblings like solar and wind, is making waves in the UK's energy landscape. And when it comes to tidal energy, there's a lot to dive into. Let's plunge into some expert insights that might just change the tide of your opinion on this energy source. As the push for green energy continues, investors are desperately looking for sources of renewable energy that will provide substantial returns, and the Isle of Wight may be the prime candidate for future tidal turbines. How do tidal turbines work, what exactly has been planned with the Isle of Wight, and what challenges do tidal systems face?

How do tidal systems work?

Of all the renewable energy sources that get discussed, tidal energy often finds itself at the bottom of the list, and yet, despite this, it can provide sizeable quantities of power. As the name suggests, tidal power is energy drawn from the natural motion of tides, whereby water moves in and out as a result of the gravitational pull of the moon and sun. 

Because there are four main tides a day (two low and two high), it is possible to generate power throughout the day, with four main peaks of potential energy generation. However, while the term tidal power is straightforward, there are numerous methods for extracting energy from the tides, which is why it is essential that the differences are recognised and understood.

The three main types of tidal power are tidal barrages, tidal fences, and tidal turbines. In tidal barrages, incoming tidal waters are captured in a reservoir which closes its gate at the highest point to trap this water. Then, when energy is needed (during low tide), this water is released through the gate, and the flowing water turns a turbine which generates electricity.

In tidal fences and tidal turbines, energy is generated whenever there is a change in tide when water flows both in and out. Tidal fences are similar to vertical turnstiles, while tidal turbines are akin to underwater wind turbines. Both convert mechanical energy from rotation into electricity, but unlike tidal barrages, they don’t require a dam to control the flow of water. 

The advantage of tidal barrages is that they are able to store energy and release it exactly when needed, but such dams can be costly. In the case of tidal fences and turbines, their ability to operate in slow-moving water makes them ideal for more continuous energy production, but they often require at least 5 meters of tidal height; otherwise, they can struggle to generate energy.

Isle of Wight tidal energy scheme in investment stage

While tidal energy may sound like an excellent source of energy, the high cost associated with tidal technologies has made their integration difficult. Considering that most energy companies are driven via profit (and quite rightly), other renewable energy sources such as wind and solar are not only easier to work with but are also cheaper. Furthermore, not all coastal regions are suitable for tidal energy systems, as not all tides are equal, with some locations having substantially larger tides than others.

However, recent reports have surfaced revealing that investors are now in the talking stages with Perpetuus Tidal Energy Center (PTEC), who are looking to install underwater turbines around the Isle of Wight coast. Originally, the project was supposed to see turbines installed around 2017, but numerous challenges, including low tidal energy prices, made the project financially unviable. Now, the PTEC is expecting to join up with investors to win a government energy contract for 2024 that could see underwater turbines installed off the shore of the Isle of Wight. 

According to a recent BBC report, the PTEC project, which was initially anticipated to commence in 2017, faced setbacks due to low tidal energy prices. However, there's renewed hope as PTEC is actively engaging with potential investors and energy firms. The project, if realised, could potentially generate up to 300MW of electricity, sufficient to power most of the Solent region.

If completed, it is believed that the tidal system will be able to produce around 300MW of energy, which is more than enough for the entire Solent region. A 30MW demonstration was initially supposed to be developed back in 2012 (using the funding raised by the Council), but this has still yet to materialise. 

While the project could usher in a new era for tidal energy, there are those who have their doubts, including the Isle of Wight council. Currently, it is believed that PTEC owes the Council around £1m after substantial investment, and one council member has described getting answers from PTEC as “trying to pull out teeth”.

Further insights from OnTheWight reveal that PTEC is gearing up to kickstart its operations at Flowersbrook by Autumn 2024. The project, which has been in the pipeline since 2012, is very much alive and is expected to significantly drive down the price of tidal energy, especially in a fluctuating energy market. The unique tidal resource around the Isle of Wight and the South Coast offers a 'deep green power' potential, attracting attention from major industries in the region.

Collaboration is the name of the game in the tidal energy sector. PTEC, for instance, has partnered with the renowned European Marine Energy Centre (EMEC) in Orkney. This partnership aims to harness 30MW of tidal energy, with the potential to expand to a whopping 300MW. And it's not just about the UK; there are international collaborations too. British turbine companies are sharing knowledge with international counterparts to drive down the costs of tidal stream energy.

Rear Admiral RP Stevens CB, the Chair of Perpetuus Tidal Energy Centre (PTEC) Ltd, passionately believes in the potential of tidal energy. He emphasizes that with the right support, especially through the government's Contract for Difference (CfD) legislation, tidal energy can be fully commercialized. Imagine this: a significant capital investment and hundreds of jobs created in the Isle of Wight and Solent region, all thanks to the power of tides!

What challenges do tidal systems face?

There is no doubt that the amount of energy stored in the tide is immense, and if properly extracted, could provide coastal nations such as the UK with plenty amounts of power in the future. However, there are a number of drawbacks that could make tidal energy difficult to implement on a large scale. 

To start, tidal systems based on dams require a large amount of investment and space as captured tidal waters need to be stored. Building such a dam inland makes little sense due to the expensive nature of the land, but building one on a coastline requires structures to be constructed on the seabed, thus requiring shallow waters. 

Tidal systems such as fences and turbines have the added advantage that they don’t require dam infrastructure, but their low efficiencies compared to tidal barrages make it difficult to turn a profit. To make matters worse, seas such as the Solent are extremely busy with maritime traffic, and installing underwater tidal turbines can restrict where boats can sail and moor. 

Tidal systems that are located further out along the coast also need to connect to the mainland via cables, and this can introduce challenges with installation costs and security. Furthermore, as the efficiency of such turbines is low, large underwater farms would be needed, and this may result in complex cable topologies that will be a technical nightmare to maintain. 

However, it is possible that the cost of tidal systems may be justified when combining them with offshore wind turbines, such that both the wind and tidal turbines share the same infrastructure. Thus, it becomes easier to maximise the energy potential for tidal installations. 

From an environmental perspective, tidal stream energy is a gem. It harnesses the gravitational pull of the moon, and its underwater sites are unobtrusive, leaving minimal impact on the landscape. Preliminary observations even suggest that marine life tends to avoid the slow-turning turbines, potentially creating artificial reefs that might enhance fish stocks. It's a win-win for both the environment and energy generation.

In conclusion 

While the widespread adoption of tidal energy remains on the horizon, technical challenges must be addressed. The Isle of Wight, with its potent tidal forces in the Solent, emerges as an ideal candidate for pioneering tidal technologies. As the UK stands on the brink of leading the global tidal energy movement, with the right backing and partnerships, we have the opportunity to harness a sustainable energy source that promises both environmental and economic rewards. The tides are turning, and a luminous future awaits!