DISCOVERING TIDAL POWER: A source of unlimited potential.

ENERGY GIRL

By Abrar Hasanat

With climate change becoming a rising concern, there has been a greater emphasis on renewable energy sources and the quest for clean energy. This has resulted in the accelerated development of novel energy-harvesting methods, such as tidal power. Humans have traditionally relied on water for a plentiful supply of resources. However, tidal energy is a vast underexplored resource that is suddenly lapping at our feet. Tidal power is not really a new concept, with humans using it for centuries. However, with the help of modern technology, we can harness the infinite force of the tides. We can use it to generate clean and renewable electricity.

So, what is tidal power? According to Brittanica, “Tidal power, also called tidal energy, is any form of renewable energy in which tidal action in the oceans is converted to electric power.”₁ Basically, our ocean is a source of unlimited energy in the form of moving water. As long as there is the movement of water in the ocean, there will be ways of producing clean energy from it. 

One might think that this phenomenon is a new discovery, possible only after the invention of modern technology. But that couldn’t be further from the truth! In fact, the earliest evidence of the utilization of ocean tides for energy conversion goes all the way back to around 900 A.D., but there were certainly predecessors buried in the oblivion of prehistory.₂ In England, a tide mill dating back to 1170 can be found.₃  However, in these establishments, electricity wasn’t generated because…well electricity itself was undiscovered back then. In the 20th century, the first commercial-scale tidal power plant was established in Britanny, France.₃

So, how is tidal energy produced? Well, first we need to convert the kinetic energy (energy produced due to the motion of a substance) into electrical energy. This can be done in the following ways:₄,₅

1. Tidal Turbines: This mechanism works in the same way that a wind turbine does. A simple turbine is submerged underwater. The water flowing across it can then drive the propellers. This system is arguably the simplest of all and has a fairly low installation cost; however, it generates less energy than other tidal-based methods. On the contrary, even though tidal turbines are more expensive to construct than wind turbines, they can generate more electricity with almost the same size blades.

2. Tidal Fence: Tidal fences are comparable to tidal turbines in design, but with one important difference: a different rotor. These devices make use of a turnstile-like architecture that spins with the flow of the water. Several variations of this design have been presented, but the most popular is a rotating cylinder structure that stands upright. This is the least common amongst the tidal technologies. As of 2020, no tidal fence projects were operating in the United States.

1. Tidal Barrage: Tidal barrages are the most effective method of capturing tidal energy. They usually require the installation of a dam-like structure which drives high-speed water through a barrage where a turbine is located. Higher water speeds equal greater kinetic energy, which equals more power. This is similar to a hydroelectric dam system in many aspects. Its two-way tidal power system uses both the incoming and outgoing tides to create electricity.

So, why should someone prefer tidal power as a source of producing energy over the other, more conventional sources? Where does tidal power have the edge? Well, we’ll discuss that now!₆,₇

• Clean And Renewable: Tidal energy is as clean and renewable as any other sustainable resource we have today. When compared to other renewable energy systems, it produces little pollutants and takes up less physical space.

• Predictable And Reliable: The tidal currents are extremely predictable. Low and high tides follow predictable patterns, making it easy to forecast when electricity will be generated throughout the day. It also makes it simple to estimate how much power will be generated by turbines because the force of tides and currents can be properly projected.

• Zero carbon emissions: Tidal power stations, in addition to being a clean energy source, do not release greenhouse gases during electricity generation. Finding zero-emission energy sources is more crucial than ever because greenhouse gas emissions are one of the primary causes of climate change.

• Long-Lasting Equipment: Tidal energy systems are naturally resistant to aging and have lengthy lifespans. Most tidal systems are expected to last 75-100 years on average. For example, a solar panel typically fades after 25-30 years. When done on a big scale, this saves time, energy, and money and is more cost-effective overall.

• High power output: Tidal turbines are 80% efficient, which is higher than solar (25%)₈ or wind (20-40%)₉ energy generators. Furthermore, even at modest speeds, the density of water allows it to power a turbine. As a result, even if the water conditions aren't optimum, tidal turbines have the ability to generate enormous amounts of electricity.

And obviously, every rose has its thorns. No technology or infrastructure in this world is perfect. Hence, this tidal power-based source also has its own shortcomings.₅,₆

• Environmental impact: While installing tidal turbines underwater may be convenient for humans, the same cannot be said for all the critters of the sea. Since the technology requires turbulent water to operate them, a big foundation must be constructed. This form of the underwater building has the potential to destroy habitat. The most egregious offender is the tidal barrage, which uses dams to obstruct the passage of sea life and potentially devastate aquatic ecosystems, making it extremely harmful for the sea life.

• High construction costs: Building structures that can survive the turbulent, corrosive character of seawater is not a cheap task. Other renewable resource alternatives offer lower initial investment costs. While tidal energy systems have extended life cycles and eventually pay for themselves, governments and companies are more concerned with their 5-year budget than a 60-year estimate. The initial outlay for these systems is sometimes the most significant impediment to future ventures.

• Scarcity Of Suitable Locations: The possible installation site must meet very precise conditions in order for a tidal power plant to be developed. For starters, they must be positioned along a coastline, which limits prospective station locations to coastal states.  A potential site must also meet additional conditions. Tidal power stations, for example, must be built in areas where the height difference between high and low tide is large enough to power turbines. This restricts where power stations may be built, making widespread adoption of tidal power problematic.

All being said, it’s understandable why tidal power hasn’t yet been embraced with open hands by everyone. The government and corporate entities are reluctant to spend the additional expenses and find suitable places when its alternatives can be done at a lower cost initially. Again, the environmental groups are also worried about how building such structures might result in the destruction of habitats of sea creatures.

However, with the development of technology, both the costs of production and their impact on the surrounding ecosystem can be reduced. It can be seen as the lesser of two evils, much better than the popular oil-based, coal-based, or other fossil-fuel-based energy source but still lagging behind its peers like solar energy in terms of cost and environmental aspects. 

Yet, this method field has huge potential, especially since it is naturally a clean and zero-carbon source. Thus, the experts only need to figure out how to reduce its effects on the ecosystem with minimal costs, and it might turn out to be the clean, fuss-free, massive renewable energy source we all are looking for in the modern age. 

Works Cited:

1. “Tidal Power.” Encyclopædia Britannica. Encyclopædia Britannica, inc. Accessed March 1, 2022. https://www.britannica.com/science/tidal-power.

2. “History of Tidal Power.” Tidal Electric. Accessed March 1, 2022. http://www.tidalelectric.com/history-of-tidal-power.

3. “History of Tidal Power.” Tidal Power - History of Tidal Power. Accessed March 1, 2022. http://tidalpower.co.uk/history-of-tidal-power.

4. “U.S. Energy Information Administration - EIA - Independent Statistics and Analysis.” Tidal power - U.S. Energy Information Administration (EIA). Accessed March 1, 2022. https://www.eia.gov/energyexplained/hydropower/tidal-power.php.

5. “7 Tidal Energy Pros & Cons: Is Tidal Power the Future?” Ecavo, June 10, 2021. https://ecavo.com/tidal-energy/.

6. Lane, Catherine. “Tidal Energy Pros and Cons.” Solar Reviews. Solar Reviews, February 24, 2019. https://www.solarreviews.com/blog/tidal-energy-pros-and-cons.

7. Walker, Kris. “Is Tidal Power a Viable Source of Energy?” AZoCleantech.com, January 22, 2013. https://www.azocleantech.com/article.aspx?ArticleID=350.

8. “Solar Generator.” ScienceDirect Topics. Accessed March 1, 2022. https://www.sciencedirect.com/topics/earth-and-planetary-sciences/solar-generator.

9. “Renewable Energy Fact Sheet: Wind Turbines.” United States Environmental Protection Agency, August 2013. https://www.epa.gov/sites/default/files/2019-08/documents/wind_turbines_fact_sheet_p100il8k.pdf.