Tidal energy is a renewable form of power generation that we obtain from the natural movements of water on our planet. As gravitational forces work to move the world’s oceans, the energy from the waves that occur as a result become the foundation of electricity and power development.
Because the tides of the oceans rise and fall naturally, tidal energy offers us a reasonably predictable resource that we can harvest to meet our current and future needs. When there is a significant difference between water levels at high tide and low tide, the potential for development is especially strong.
The United States at this time does not currently maintain or operate a tidal energy plant. There are very few potential locations where such an energy resource could be developed in the first place.
This technology is proven to work thanks to installations like the Sihwa Lake Tidal Power Plant in South Korea. It offers 254 megawatts of power and has shown consistency in its capability to produce energy since coming online in 2011. The Rance Tidal Power Station has also been operational for over 45 years.
These are the pros and cons to consider when looking at the development of tidal energy in the future.
List of the Pros of Tidal Energy
1. Tidal energy facilities have lower operational costs.
Once you exclude the initial capital cost of developing a tidal energy facility, it is one of the most inexpensive resources available to us right now. Some locations are able to generate electricity for as little as two cents per kilowatt hour. No other form of renewable energy that is available today can match this cost profile.
2. Tidal energy facilities offer efficient energy production ratings.
Tidal energy generation is one of the most efficient ways to create power in the world today. Modern plants are able to achieve an 80% efficiency rating. That is 50 percentage points higher than what the average coal-fired power plant currently produces. It is even ten percentage points higher than other forms of renewable energy. When you add in the fact that there are no radioactive concerns with power generation as there would be with nuclear energy, it is easy to understand why countries want to look at developing this resource.
3. Tidal energy facilities have a longer useful lifespan.
When the first nuclear power plants were constructed, the expected lifespan of each facility was approximately four decades. Ongoing improvements and technological advancements have extended this timeframe by another 30 years. Some estimates give these facilities up to 70 years of additional life. When you look at title energy, there are facilities which have been in operation for more than 50 years. They are producing the same amount of power for use in their communities today as they were when they first came online.
4. Tidal energy generates power with minimal water movements.
One of the most common forms of renewable energy that we harvest from water supplies comes through a hydropower station. Often built on a river and housed in dams, this form of production sometimes requires up to 23,000 ft./s of water movement.
That is why some rivers are not suitable as a power generation resource.
When a tidal energy facility comes online, you can begin generating power from some of the smallest water movements. Waves that are just 3 ft./s can produce enough power to move the turbines in the facility. That means the opportunities for power creation are up to 1,000 times greater than they would be using “traditional” solutions.
5. Tidal energy offers a predictable resource for power.
One of the most significant disadvantages of using renewable energy resources is that the primary source of generation is unpredictable. Some forms of solar energy can be influenced by clouds in the sky. Wind energy is not always possible even when turbines could be spinning due to the current limitations of that technology. We must use batteries and other methods of storage when using them to fill in the gaps when additional power is not being created.
The only form of renewable energy that is comparable to the tidal forces of the ocean is geothermal. Both are reasonably predictable for the amount of electricity we can generate from the facilities each day.
6. Tidal energy is a 100% renewable resource.
Once engineers get beyond the initial fossil fuels investment required to build a tidal energy facility, this resource is one of the few assets that we have that creates a 100% renewable product. The only way that we would be unable to take advantage of this resource would be if the oceans disappeared, the planet stopped orbiting the sun, or the moon was to explode suddenly. Since none of those options seem likely, we can rely on this method of power generation to fulfill many of our needs.
7. Tidal energy is an eco-friendly form of electricity creation.
Once a facility goes online, tidal energy does not create greenhouse gas emissions which could be potentially dangerous to our atmosphere. Although there is a small investment that must be made to develop a power station in the first place, most facilities are able to see their net emissions savings begin in less than five years. This technology also requires less space than traditional forms of power generation which rely upon fossil fuels. That means we have more usable land to use for other purposes.
8. Tidal energy is a proven power generation resource.
We have been collecting information about tidal energy power generation for over five decades. This data shows us that the environmental impacts of this technology are minimal. Every facility that has become operational around the world comes to this conclusion. If the equipment is installed correctly, then we can produce electricity without creating an adverse impact locally.
List of the Cons of Tidal Energy
1. Tidal energy facilities must guard against corrosion.
Most tidal energy facilities are located near ocean shores because that placement offers the most potential water movement. The equipment is under constant threat from the salt in the water, and the air as energy collection activities occur. Even when the items are given a coating that is resistant to the corrosive atmosphere, there is no guarantee that this will extend the life of the object in question.
Although there are lower maintenance costs associated with this form of power generation, most of the studies that compare this option to our traditional resources are only short-term observations.
2. Tidal energy facilities are always under the threat of damage.
As human populations expand, the amount of space that we require continues to grow. Because these facilities are located near a shoreline where wave movements are necessary, you can become a natural attractant to some individuals. Not only is there the threat that a strong wave could rip apart some of the equipment in the facility, but there is also the problem of having people, debris, or animals being caught in the undertow the structures might generate. Even with proper warning signs in place, it is not 100% possible to predict human behavior.
3. Tidal energy facilities must account for “king” tides.
Although tidal energy is a predictable resource, the actual movement on the water changes over a 30-day period. There is a time during each window where a huge tidal event occurs. These facilities can take the additional pressure from the most massive tides of the month (or the year) without much trouble. The issue here is that the placement of the facility could change how the waves come in during these times. It is possible that the facility could change how the water movements occur, thereby disrupting the potential for electricity and power creation.
4. Tidal energy facilities can change the structure of the water.
When tidal energy facilities first come online, the environment works to adapt to the changing circumstances. One of the ways that it does this is through a change in the salt levels found in the water. This process can create harm for the natural habitats that marine life use in the region. Although it won’t create fresh water from ocean tides, these facilities can reduce salt levels enough to cause harm to the fish in the area.
5. Tidal energy facilities can alter the regular patterns of water movement.
Beaches form because of how the waves move sentiment up and down the coastline. It is a constant ballet of removing items to then replace them. When a tidal energy facility goes online, the shift in wave patterns that can happen may impact the actual movement of the water.
Some facilities may discover that the movements they wanted to use for power generation become less intensive (or go away completely) because the equipment altered how the waves come to shore.
6. Tidal energy facilities are not cheap to create.
The primary reason why the United States is not researching tidal energy as a viable resource is because of the cost required to bring a new facility online. The Severn Estuary in the United Kingdom proposed to add 8000 MW to the power grid at the cost of roughly $15 billion. The Philippines is looking at the installation of a facility that would produce 2200 megawatts at the expense of $3 billion.
7. Tidal energy does not create a lot of electricity.
For over 45 years, the largest tidal energy facility in the world was able to produce 240 MW of output capacity. Only the Sihwa Lake Tidal Power Station in South Korea was able to eclipse that figure, and even then, it only produces 254 MW. Some of the facilities that are in operation around the world deliver minimal output capacity. A facility in Russia only generates 1.7 MW each year.
8. Tidal energy facilities may create unknown environmental consequences.
One of the most significant advantages of tidal energy is that the impacts it makes on the surrounding environment are usually minimal. Although we have over 50 years of data to suggest that we can incorporate this power resource successfully, the long-term information for this technology is still missing. We must continue to study how wildlife interacts with facilities like these to ensure that we are helping our planet instead of harming it unintentionally.
The pros and cons of tidal energy give us another solution to consider as we begin to look at ways to wean ourselves off of fossil fuel resources. Because there are only a handful of sites in the world today which are suitable for this technology, its development is moving slower than other forms of renewable power. Since it is a provable resource for new electricity, innovations in this field could one day make it possible for us to transition to this resource and limit greenhouse gas emissions.
Brandon Miller has a B.A. from the University of Texas at Austin. He is a seasoned writer who has written over one hundred articles, which have been read by over 500,000 people. If you have any comments or concerns about this blog post, then please contact the Green Garage team here.