Breaking Waves: The Pros and Cons of Tidal Energy

How Does Tidal Energy Work?

There are many proposed ways to take advantage of tidal energy, with all but one of them already currently in usage at one scale or another.

Tidal stream generators directly harness the tides to spin turbines. Their placement areas include inlets and straits where water reaches considerable velocity as the tides come in and out. Perhaps the easiest way to think of them would be as underwater wind turbines.

Tidal barrages are a type of controlled dam. By allowing the water to flow into an enclosed area during high tide and then controlling the return of the water through sluice gates. Turbines can be placed in the gates, allowing the generation of electricity as the tides go back out.

Tidal lagoons are similar to barrages, but the proposed area enclosing waters at high tide is artificial. Through clever usage and spacing, they’re a proposed solution to the fact that most tidal zones will only allow for roughly ten hours of power production per day.

Lastly, dynamic tidal power is a proposed solution to the ecological impact of many of the tidal generators which are in use. By creating a concrete structure of enormous length in a T-shape, the idea is to harness the majority of the tidal currents which run parallel to the coast instead of directly into it.

DTP is untested at this point, but the science behind it seems to be quite solid and it solves the majority of the problems associated with tidal power. The issue, at this point, is that it’s a risky venture since a smaller demonstration model isn’t a viable option for testing since even a kilometer long dam built for this purpose is going to generate virtually no power.

The Pros of Tidal Power

While no energy is truly free, tidal power has some pretty impressive promises. The advantages of this form of power are pretty impressive.

• Renewable-Tidal energy is pretty much endlessly renewable, so long as we have a moon there are going to be tides after all.
• No Emissions-Tidal energy creates no emissions due to the way it works. The energy is already there and the carbon footprint will flatten out quickly despite the relatively large amount of materials which goes into the construction of the plants.
• Predictable-Much like wind energy, tidal power is extremely reliable and predictable on a long scale. With proper mapping, a structure can be designed to provide a very reliable source of energy.
• Low Running Costs-The running costs, after the initial construction, of most forms of tidal power, are quite low. As long as everything is designed correctly only minimal maintenance will be needed and there’s no need to work with logistics companies to transport fuel.

It’s not a miracle power source, but there’s definitely a lot to be said for using tidal power.

All of this does come with some pretty steep disadvantages, however.

The Cons of Tidal Power

Unfortunately, while all seems well with this renewable source of power right out of the gate, there are some serious issues associated with its usage:

• Environmental Impact-While tidal power doesn’t contribute to emissions, each plant has a rather massive environmental impact. Stream generators, for instance, can harm aquatic life and marine life, in particular, is extremely specific in its adaptations which means projects like DTP have an unknown, large-scale impact.
• Expensive to Construct-Tidal power plants are massive undertakings, and their upfront costs are extremely high.
• Limited Power Generation-While reliable, tidal power is only able to be harnessed for a limited amount of time during the day. While dynamic tidal power plants forego this, they’re still largely untested.
• Limited Locations-Tidal power can only be generated in certain areas. On top of that, massive infrastructure creation needs to take place in order for the power to be harnessed to the grid at large in most nations.
• Maintenance is Difficult-By their very nature, these plants are hard to perform maintenance on. Any machinery will inevitably require work to be done on it, no matter how well designed, and there are some serious difficulties associated with maintaining this kind of power.

While the environmental impact is the only insurmountable issue associated with tidal power, it’s a big issue considering all of the damage which has been done to aquatic and marine ecosystems already.

Tidal power has fallen behind other renewable energies for these reasons and currently is barely included in the dialogue when people talk about renewable and sustainable energy sources outside of certain niche circles.

Does Tidal Power Have a Future?

Currently, tidal power has seen some limited real-world usage, and while tidal stream generators are the most “mature” of the technologies no real standard has been achieved yet. The largest generator currently in use is the Sihwa Lake Tidal Power Station in South Korea, which generates only 254MW of energy.

There are many proposals for stations with a larger capacity, but currently, only the United Kingdom is building tidal power stations of any considerable size.

The disadvantages of tidal power seem to largely outweigh the pros, even when they’re looked at as only a small portion of a larger solution. Frankly, solar and wind energy are still leading the world of renewable energy by a massive margin, with hydropower falling closely behind, and all of these sources of energy have far fewer disadvantages than tidal energy generation.

The impact on the marine environment is probably the largest concern in most cases. In addition to harming sea life, large-scale plants also have the potential to ruin sea views and limit human usage of near-coastal waters which are often used for recreation.

All of this adds up to a rather dim future for this seemingly endless energy source, and it may relegate tidal energy to being only a last-ditch option in the future.

The technology is still somewhat immature, however, and it may be subject to more change than any green source of power with the exception of nuclear energy.

However, DTP plants have a massive power output potential and some companies have begun exploring tidal arrays which are placed on the sea floor a long distance from shore and then channel power back.

The Effects of Changing Technology

While the currently proposed tidal energy arrays tend to be rather cumbersome affairs, and they may not be the best option for any but niche usage, many of the proposed technologies are still blossoming.

In short: it’s hard to predict just where tidal energy will go. Large-scale energy generation with current technology doesn’t seem feasible, or convenient, but we don’t quite know where things are headed yet as there is no real standard in place.

It’s an exciting technology to look forward to, however, and if the large issues which are inherent to the process can be managed properly then it may have a definite place in the future of renewable energy development.

The Takeaway

If you remember nothing else about tidal energy, you’ll want to know the following:

• Tidal energy is still in its infant stages, despite the first plant having been opened in 1966. There is no standardized method of harnessing the tides and new methods are currently in development.
• In its current state of development, tidal power isn’t feasible as a large-scale energy solution. This may change in coming decades, but the tech simply isn’t there yet.
• There are methods which work around most of the problems inherent to tidal energy generation, but they are largely untested at this point and none address the environmental impact adequately.
• While the disadvantages seem to outweigh the good stuff at this point, the sheer scale of power which can be offered in the future means that tidal development is still something worth investing in and following.
• Sea-floor arrays and dynamic tidal power are already in development, meaning that the solution to the major issues may come forth sooner than expected.

Tidal power is a developing technology, making it hard to predict where it’s place in the world will be. The scale of power makes it an attractive investment, however, especially if the issues surrounding the time-scale and environmental issues can be surmounted.