Talking tidal as MeyGen kicks into gear

28 June 2018 (Last Updated June 23rd, 2020 15:28)

This March, Atlantis Resources announced that construction had been completed on Phase 1A of the MeyGen project, the world’s largest tidal power plant, and that the project has now formally entered its 25-year operations phase. So what will MeyGen do, and will similar projects soon follow?

Talking tidal as MeyGen kicks into gear
The MeyGen tidal energy project, operated by Atlantis Resources, has the potential to change how tidal power is seen on the global stage. Image: Atlantis Resources.

Tidal power is globally underutilised, despite having huge potential as a future energy source due to the predictability of the tides compared with wind and solar power sources. A lack of the suitable sites for plants and the high level of investment needed to get facilities up and running have led many countries to rely on the more traditional methods of power generation.

The MeyGen tidal energy project, operated by Atlantis Resources, has the potential to change how tidal power is seen on the global stage. The largest energy plant of its kind in the world, MeyGen is currently under construction in the Pentland Firth between the Orkney Islands and mainland Scotland, at the northern tip of the United Kingdom. The lease for the project was approved in 2010, and in April this year, construction of Phase 1A of MeyGen was completed and so the project officially began operations.

Record-breaking tidal power generation

With the completion of the initial stage, MeyGen has commenced its 25-year operational phase. MeyGen’s first phase involved the deployment of four turbines on a gravity support structure. According to Atlantis Resources director of project delivery David Taaffe, these 1.5MW turbines generate enough energy to power 2,600 homes.

“Phase 1A of the MeyGen project included the assembly, construction, installation and grid connection of four 1.5MW, 200t tidal stream turbines, one from Atlantis Resources and three from Andritz Hydro Hammerfest,” Taaffe explains.

“The machines are geared to provide technical and environmental information which we need to optimise MeyGen’s next phase, when four further turbines will significantly increase output.”

Phase 1A acts as a precursor to the remaining 86MW potential of the project, with the installed environmental monitoring equipment demonstrating the viability of the MeyGen facility, as well as tidal array projects generally.

MeyGen’s Phase 1A turbines feed into the onshore power conversion unit at the Ness of Quoys distribution network, operated by Scottish Hydro Electric Power Distribution (SHEPD) through one of the longest 33kV underground power export cables in the UK.

In August 2017, the MeyGen site broke the world record for electricity generation at 700MWh, according to an update on the project’s progress by Atlantis Resources. Enough power was generated in the month of August to power 2,000 Scottish homes, despite only two turbines being operational. At the time, Taaffe remarked that he expected the station’s performance to only improve, saying, “we expect to continue to break records throughout the rest of the year, generating both predictable power and revenue.”

A 2014 study from engineers at the universities of Oxford and Edinburgh claims that the Pentland Firth tidal flows could generate enough power for nearly half of Scotland’s needs, and MeyGen’s performance so far looks to be the first realisation of this latent potential.

Turning the tide

Despite tidal power’s incredible potential as a renewable energy source, not only for Scotland but globally as an answer to diminishing fossil fuel reserves, the practice of harnessing the tides for power generation purposes is hindered by the limited availability of suitable sites for tidal energy plants.

So choosing MeyGen’s Pentland Firth site was no small matter. “Sites like the Pentland Firth are regarded as premier locations from which to harness the power of the ocean’s currents,” says Taaffe. “Despite their remoteness, these areas also have manageable water depths, proximity to a grid connection, adequate port and road infrastructure and a supportive local community, all of which play important roles in the development of energy projects at scale.”

Scotland has some of the most powerful tides in the world, and projects such as MeyGen are quickly solidifying the country’s tidal energy supremacy. Taaffe believes the completion of Phase 1A positions Scotland as the leader in tidal power generation and innovation, saying that “with an estimated 25% of Europe’s tidal potential, it is no surprise that Scotland reigns supreme.

“As well as suitable geography, Scotland provides a full suite of engineering capabilities based on its longstanding heritage in offshore energy development. Tidal power makes use of nearly 50 years of pioneering oil and gas extraction from the North Sea.”

Having access to a site with such strong tides has its downsides though. After all, equipment still needs to be installed and maintained for the site to run at full efficiency, yet the tides can make this tricky. “The best tidal energy sites are located in areas with the highest tidal flows. By nature therefore, there are limited periods where the tide is slack and hence we must operate with small installation windows,” explains Taaffe.

Fortunately, both Atlantis and Scotland have extensive experience in the offshore wind, oil and gas sectors, so both are used to working around the extreme conditions the North Sea can bring.