By Kenzie Lewis

Tidal energy is a technology that’s really making waves in the field of renewable energy. Let’s take a dive into what tidal power is, how tidal power is harnessed, and where we can find tidal power being used all over the world!

What is Tidal Power?

Tidal power relies on the kinetic energy of water moving in the ocean due to the tides. The tides are special surges that move through the ocean twice a day, and they’re caused by the gravitational pull of the moon and the sun [1]. When the tides meet the shoreline in some areas, they can produce very strong currents that are capable of producing enormous amounts of power; in fact, if we could completely harness all of the power from the tides using tidal barrages, we’d have about 3000 billion watts worldwide [2]. That’s enough to power roughly 2 billion dishwashers [3]!

What Advantages and Disadvantages Come With Tidal Power?

Tidal power may have a lot of potential, but does this energy source really have anything special to offer to the energy mix? Well, with energy like solar or wind power, it can be difficult to predict the weather conditions, so it’s hard to know how much energy you’re going to get and when you’re going to get it. But as sure as the sun rises everyday, we know exactly when the tides will rise and fall, so tidal power is seen as incredibly reliable [4]. Tidal energy is also a renewable source of energy, so adding it to the energy mix could help to lower greenhouse gas emissions and mitigate the negative effects of climate change. Unfortunately, this technology also comes with a few challenges. For instance, there’s only a few places around the world where tidal power could be implemented. The more common type of tidal power technology, which is known as tidal range technology, has less than 10 places around the world that see a large enough tidal range to produce a worthwhile amount of power [5]. Tidal stream technologies could be implemented in other locations, but this technology is still being developed. There are also concerns about the impact of tidal range technology on ecosystems. The Annapolis Generating Station, which was located in the Bay of Fundy right here in Canada, was actually shut down in 2019 due to the impact of the turbines on fish mortality [6]. However, with more research and development, both of these disadvantages can certainly be minimized.

How Is Tidal Power Harnessed?

Tidal power is harnessed through two methods: tidal range technology and tidal stream technology. Tidal range uses the difference in height between high and low tide to trap large amounts of water in a dam [7], and then releases the water through turbines to generate usable electricity [8]. These dams are known as tidal barrages, as shown in Figure 1, and are the more commonly used technology.

Figure 1: Original gif can be found here.

The other kind of tidal technology, tidal stream, relies on the strong currents that are produced as a result of the tides. Similar to wind turbines, the currents push turbine blades in order to convert the energy from the tides into electrical energy. Since water is more dense than wind, these turbines are capable of producing a lot more electricity than wind turbines. However, it’s important to realize that tidal turbines need to be a lot more sturdy to handle water currents than wind currents, so they are a lot more expensive and difficult to manufacture. This is one of the main reasons as to why tidal stream technology still requires research and development before it can be more widely implemented [9].

Figure 2: Original gif can be found here.

Where is Tidal Power Being Used?

Figure 3 shows a map indicating areas where tidal power could or is being used due to tidal resources that are locally available. Even though tidal power isn’t available everywhere around the world, it does have the potential to make a big difference around these areas- for instance, at least 500 MW of energy are available from the tides in Chile [10].

Figure 3: Original image can be found here. The dark blue areas indicate higher potential for tidal resources, the light blue indicates moderate potential, and the grey area indicates a lack of potential.

We can only expect AI to become more prevalent in oil fields and offshore drilling platforms [5]. The challenges of sustainability, worker safety, and resource availability will not be going away anytime soon. New AI tools will become essential to retain high profit margins in the oil and gas industry, as new reserves become increasingly difficult to access [2]. New algorithms will need to be developed to predict equipment failure, automate dangerous work, analyze reserves, and identify sources of emissions. Although it may not be Silicon Valley, thousands of bright software engineers will be needed to help spearhead these technologies in order to meet the challenges of the 21st century.

Tidal power can also be found in areas of Canada. Nova Scotia, which is home to the famous 15m Bay of Fundy tides, is estimated to have about 7200MW of potential power [11]. The Annapolis Generating Station, which was commissioned in the Bay of Fundy in 1984, was a tidal power station with a 20MW nameplate capacity. This station used tidal barrages to take advantage of the huge tidal range provided in the area. Unfortunately, as mentioned earlier, a significant portion of the fish population in the area were killed when passing through the turbines, so the facility was decommissioned in 2019. Since then, other facilities, such as the Fundy Ocean Research Centre for Energy and the PLAT-I platform. Have been created to further test tidal energy potential in Canada. Researchers are being a lot more cautious about the impact of this technology on wildlife by using less invasive stream technology instead of barrages. PLAT-I has four turbines mounted on hydraulic lifts, for example, so they can be raised in and out of the water easily [12].

With the amazing potential to provide enormous amounts of renewable energy, some might say tidal power can truly turn the tide against climate change! In the future, we can look forward to seeing improvements to minimize the impact of tidal technology on local ecosystems and reduce the cost of durable tidal turbines in order to implement tidal power in more locations. If these improvements are made, I believe that we can expect to see tidal power making a big splash in the future!

References

[1] National Oceanic and Atmospheric Administration, “What are tides?” National Ocean Service, Feb. 2021. [Online]. Available: https://oceanservice.noaa.gov/facts/tides.html

[2] N. E. Selin, "Tidal power," Encyclopedia Britannica, Apr. 2019. [Online]. Available: https://www.britannica.com/science/tidal-power

[3] “How Many Watts Do You Need to Run the Average Home and Appliances?” Modernize, Oct. 2019. [Online]. Available: https://modernize.com/homeowner-resources/solar/watts-run-average-home-appliances

[4] National Oceanic and Atmospheric Administration, “What are tides?” National Ocean Service, Feb. 2021. [Online]. Available: https://oceanservice.noaa.gov/facts/tides.html

[5] R. B. Alley, S. Blumsack, D. Bice, M. Feineman, and A. Millet, “Conventional hydroelectric dams,” in Energy, Environment, and Our Future, The Pennsylvania State University, 2018. [Online]. Available: https://www.e-education.psu.edu/earth104/node/1067

[6] “Hydro & tidal power,” Nova Scotia Power, 2021. [Online]. Available: https://www.nspower.ca/cleanandgreen/renewable-energy-sources/tidal-power

[7] Center for Operational Oceanographic Products and Services, “Tidal datums,” National Oceanic and Atmospheric Administration Tides & Currents, 2021. [Online]. Available: https://tidesandcurrents.noaa.gov/datum_options.html

[8] A. Farris and C. Helston, “Tidal power,” Energy BC, 2017. [Online]. Available: http://www.energybc.ca/tidal.html

[9] M. Woo, “Tidal energy: The new sustainable resource,” Wood Harbinger, Mar. 2017. [Online]. Available: https://www.woodharbinger.com/tidal-energy-sustainable-resource/

[10] R. Karsten, “Tidal energy resource assessment map for Nova Scotia,” Report to OEER/OETR, 2012. [Online]. Available: https://marinerenewables.ca/wp-content/uploads/2012/11/Karsten-BoF-Map-Final-Report.pdf

[11] A. Pope, “Testing the future of tidal energy in Nova Scotia,” Canadian Geographic, Aug. 2019. [Online]. Available: https://www.canadiangeographic.ca/article/testing-future-tidal-energy-nova-scotia

Tidal Energy: The Power That's Making Waves