What is Tidal Power? Pros and Cons of the Clean Energy

It’s no secret that the world desperately needs alternative energy solutions to the burgeoning climate crisis. Countless plans to collect energy from natural sources have been posed, some more realistic than others. Tidal energy is among the more feasible, along with wind and solar power. It is also one of the most powerful possible solutions due to its relative dependability and the immense size of the oceans. Additionally, it can improve the lives of people living in cities and small, secluded communities around the world.

What is Tidal Power?

Tidal power is the energy that’s harnessed from the rise and fall of the tides to create electricity. One of the reasons that tidal power is so interesting is that it is dependable. The power and size of tides vary around the world and are created due to the gravitational pull of the moon and sun in tandem with the rotation of the earth. This makes their arrival highly predictable, unlike weather-dependent renewable sources.

Historically, tidal power has been harnessed in Europe and North America for 1,000 years. The mills, usually located on grain farms, collected tidal water in large ponds during high tides. As the tides receded, the released water spun the waterwheels, generating energy.

Types of Tidal Power Systems

Some of the most common tidal power systems are the tidal barrage, tidal turbine, and tidal fence.

Tidal Barrages

Tidal barrages are large structures that resemble dams. These barrages are placed across lintels of oceans or lagoons and have sluice gates that control water flow. Unlike tidal fences and tidal turbines, which capture energy in one direction, tidal barrages are two-way systems. They generate energy as water rushes in with the high tide and again as it flows out during the low tide.

These are the most common tidal power systems in the world today.

Tidal Turbines

Next, the tidal turbine is very similar to a wind turbine because it also uses large blades to spin a shaft to create energy. It sits on the sea floor in an area where the tides are strong. They are sturdy devices that are very expensive to create but can produce more energy than wind turbines with the same-sized blades.

Tidal Fences

The tidal fence is similar to a tidal turbine which is mounted on the sea bed. As the name suggests, they are underwater fences with vertical axis turbines spaced along its length. As the ebb and flow of the tides pass through them, they create electricity. They are much cheaper and easier to build than tidal barrages and tidal turbines and are ideal for the strong tidal currents often found in channels and straits between land masses.

Is Tidal Power Used Today?

Tidal power is used today but not as widely as other alternative energy forms. Scientists and researchers believe that it has great potential but has yet to be harnessed in any significant amount.

Right now, several tidal power barrages are in operation; there is one in South Korea, France, Canada, Russia, and China.

The largest is in South Korea and can generate 254 megawatts of energy. The Canadian barrage in Nova Scotia is the third-largest of its kind and can generate only 20 megawatts of energy. Unfortunately, there are no commercial barrages in the United States yet. While some investment has occurred, many potential sites simply don’t generate enough tidal power to justify the construction costs. The United States has three pilot projects: the Roosevelt Island Tidal Energy (RITE) Project Pilot, the Western Passage Tidal Energy Project, and the Cobscook Bay Tidal Energy Test Site.

Advantages of Tidal Power

First and foremost, tidal power is clean. It is a natural source of energy that could, in theory, help to replace the world’s dependence on coal and oil. This transition, whether entirely to tidal, solar, or wind power, or some combination of these and others, is crucial to preserving the world as we know it for future generations.

Another more specific advantage is that tides are more predictable than either the wind or the sun. This predictability makes it easier to integrate tidal power into the electricity grid, as energy production can be reliably planned for.

When used economically and effectively, some estimates, such as those produced by the US National Renewable Energy Laboratory, suggest that up to one-third of the United States’ power could be taken from the oceans. They add that another advantage of the technology is that it could be altered to fit the size and cost point. Remote communities and larger cities could benefit from it. For example, the Ocean Renewable Power Company, and their site in the Kvichak watershed in Alaska, is already helping remote communities with their tidal power system.

Disadvantages of Tidal Power

Unfortunately, tidal power does have some downsides, which are mainly responsible for the fact that it has yet to truly take over in any meaningful way. Tidal energy is relatively expensive in comparison to other clean energy sources, and there are fewer truly good high-tide sites where the energy can be collected. For energy collection to be effective, tides must have a range of at least 10 feet. Its total availability has suffered for these reasons.

There is another important disadvantage to take note of–the effect on the marine environment. Unlike solar panels and windmills, tidal stations can have a detrimental impact on nearby plants and animals. The tidal level is often affected by these stations, as is the turbidity and an animal’s ability to navigate.

Despite these setbacks, there have been technological advancements over recent years that should lessen the cost of the process and broaden the locations from which tidal power might be collected.

New Innovations in Tidal Energy

Today, more companies are working on tidal energy solutions than ever before. Yale E360 states that there are 30 tidal and 40 wave energy companies working on the problem.

As companies work hard to create solutions to the economic problem as well as the potential environmental impact, new progress is being made. Modern tidal systems can work effectively without damaging the life around them. It is likely, Yale Environment states, that the future of the industry rests in sea-bottom-mounted or floating turbines. These devices could safely capture the energy of currents.

Companies worldwide, such as DCNS in France, CWE in Australia, and Azura, are working to create new systems. One promising development is a grid array made up of 240-kilowatt buoys created by Carnegie Wave Energy in Australia.

Some other possibilities include axial turbines (underwater windmills) and the tidal stream generator that extracts energy from moving tides. The latter is one of the least environmentally damaging solutions.

With these innovations, it is becoming more and more likely that tidal energy will decrease in cost and start to level out with solar and wind power, making it a more competitive and attractive renewable energy source.

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