Tidal Streams & The Exciting Potential of Marine Energy

Aerial view to ocean waves. Blue water background By Ivan Kurmyshov

SAE Renewables, headquartered in Edinburgh, Scotland, has quietly been laboring away in northern Scotland for more than a decade on an elusive target—that of a predictable, renewable marine energy source. In late February 2023, the firm would announce achieving just that, and, in doing so, may have changed the face of the global energy transformation as we know it.

It All Comes Down to the Firth

The Pentland Firth is a Gaelic term for the Orcadian Strait, a narrow strip that separates the Orkney Islands from Caithness in the extreme north of Scotland. This small area is a harsh marine environment and boasts some of the fastest tidal currents in the world. It also just so happens to be the home of the European Marine Energy Center, where developers can test new tech in open sea trials. For these reasons, SAE Renewables chose this seemingly inhospitable place to build a state-of-the-art tidal stream array. 

Thomas Adcock, an Oxford University engineer studying the Firth, describes, “Pentland Firth promises to be one of the best sites in the world for tidal power. What our research shows is that it could potentially generate power equivalent to almost half of Scotland’s annual electricity consumption.” 

What is a Tidal Stream Array? 

A tidal stream array is simply a configuration of tidal turbines ensconced in a specific area of a tidal stream to generate electricity. Tidal turbines work similarly to the functionality of wind turbines. However, instead of using wind, they employ water flow to generate electricity.

SAE Renewables developed the “MeyGen” array, engineered with four 1.5-megawatt turbines. Collectively, the system has a total capacity of 6MW when at full capacity. This system has been in operation as far back as 2017, but many hurdles have presented themselves along the way. 

In such a harsh environment, the MeyGen’s systems are constantly taking a beating. Because of that, reliability has been an issue. Obstacles overcome, Graham Reid, CEO of SAE, announced a global first – “our tidal stream array off the coast of the Pentland Firth became the first tidal stream array in the world to generate 50GWh of electricity,” he said in a posted statement. 

Reid would go on to describe this renewable mike drop as a “significant milestone in delivering tidal stream power at scale.” Taking into account all other tidal energy-generating devices and sites the world over, these only can produce around 50% of what the MeyGen can.

The Potential for Delivering Tidal Stream Energy At-Scale

The potential of marine energy is incredibly significant. The oceans contain vast, largely untapped power through waves, tides, and currents. These natural processes can be harnessed and used to generate electricity where other systems might not be feasible. According to the European Union’s Research and Innovation Consortium, the potential global market of tidal power is between 150-800 TWh (terawatt hours) per year, or up to $42.4 billion per year—capable of powering at least 10% of Europe’s power over the next several decades.

There are several distinct advantages to generating electricity utilizing marine-borne energy including: 

  • Sustainable: Marine energy is a clean, renewable energy source that produces no greenhouse gas emissions or other pollutants. 
  • Sheer potential: A virtually unlimited energy supply is available because the oceans cover more than 70% of the Earth’s surface. Although there may be some limitations, which we’ll explore more below.
  • Predictability: Tidal and wave energy can be far more predictable than alternative renewable energy sources, such as wind and solar power.
  • Smaller footprint: The footprint of tidal stream projects is relatively smaller than that of other comparative renewable systems.

However, there are also challenges to developing marine energy technology. One of the main challenges is the high cost of capital associated with the infrastructure and deployment of these marine energy devices. There are also a great many technical challenges associated with operating in a harsh marine environment, not to mention transmitting electricity from offshore installations to the grid.

These limitations notwithstanding, many countries are investing heavily in developing marine energy technology. A booming interest in this sector may mean reducing dependence on fossil fuels and meeting climate goals. “As the only predictable renewable energy source, and one with no visual impact, tidal stream energy can play a vital role in the UK energy mix, supporting UK energy security and being a key contributor in our journey to net zero,” says the SAE website.

Is Marine Energy Sustainable?

Marine energy definitely holds the potential to be a sustainable energy source. However, it all depends on how the technology is developed and managed. 

Consider the following:

  1. Environmental impacts: Like any energy source, marine energy can have ecological impacts, particularly on marine ecosystems. The installation of tidal turbines and other devices can affect fish and myriad marine life, and there may also be risks of noise pollution and disturbance of seabed sediments. Like the cobalt mines employing child slave labor and wreaking havoc on the environment in the Democratic Republic of the Congo, even a good idea can face harsh realities. It is essential to carefully assess and manage these impacts to ensure sustainable marine energy development.
  2. Resource availability: The energy potential of the oceans is vast, but it is not unlimited. Tidal energy, for example, depends on the gravitational pull of the moon and the sun, which means that it is subject to natural variations over time. Careful monitoring and management of these energy resources is critical to ensure both sustainability and feasibility over time.
  3. Technology development: As with any new technology, developing marine energy devices is ongoing. Continued research and development are necessary to improve efficiency and reduce costs. Developments will help to ensure that marine energy is a competitive and sustainable energy source in the long term.
  4. Policy and regulation: Effective policies and regulations are necessary to promote the sustainable development of the burgeoning field of marine energy. This includes protecting marine ecosystems, ensuring fair access to marine energy resources, and supporting collaborative research and development. In order to truly be effective, world powers must work together for the common good—no small feat.

Suppose, if you will, that marine energy is developed and managed sustainably. If that were the case, it clearly has the potential to be an essential part of the global energy transformation. It will provide clean and renewable energy to help meet the world’s growing demand for electricity. When paired with other moonshots like Bezos’ lunar solar array project, moonshots might actually be more reality than a mere concept.

“We’re Going to Need Oil for At Least Another Decade”

The underlying theme of projects like lunar solar arrays and tidal arrays is that these developments are contributors to the changing global energy mix. While still in their infancy or even conceptual stages, many renewables must overcome the feasibility hurdle. In a recent State of the Union, President Biden drew applause from both sides of the political aisle when he reiterated, “We’re going to need oil for at least another decade….and beyond that.” 

Still, as our society transitions from fossil fuels, technology like the MeyGen can help usher in a smoother evolution. As oil and gas majors lead investment in alternative energy, vilifying them as many in the President’s inner circle continuously do, including Energy Secretary Granholm, is simply misinformed. 

The President’s off-script remarks demonstrate at least some form of cogency that even he agrees that oil and gas play a huge role in energy security and the changing global energy mix.

Author Tyler Reed

Author Bio

Tyler Reed began his career in the world of finance managing a portfolio of municipal bonds at the Bank of New York Mellon. Four years later, he led the Marketing and Business Development team at a high-profile civil engineering firm. He had a focus on energy development in federal, state, and local pursuits. He picked up an Executive MBA from the University of Florida along the way. Following an entrepreneurial spirit, he founded a content writing agency. There, they service marketing agencies, PR firms, and enterprise accounts on a global scale. A sought-after television personality and featured writer in too many leading publications to list, his penchant for research delivers crisp and intelligent prose his audience continually craves.

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