Tidal energy is a source of renewable power that comes directly from the ocean. When the waters rise and fall each day, the movement creates tides and currents that allow turbines to spin so that electricity generation is possible. Engineers first introduced this contact in the 20th century so that areas with a significant tidal range could benefit from the movements of the water.
It would be fair to say that energy production using this method is still in its infancy. Although some installations have been online for over 40 years, there are only a handful of commercially viable power plants that use this technology around the world. The largest facility is the Sihwa Lake Tidal Power Station in South Korea, while the oldest one is still producing energy in La Rance, France.
England, China, Canada, and Russia have significant potential when considering this renewable power resource. The United States doesn’t have a tidal energy plant, and there are only a few sites where the electricity could be produced at a reasonable price.
Several advantages and disadvantages of tidal energy and power are worth considering as the world looks for new ways to move away from fossil fuels.
List of the Advantages of Tidal Energy and Power
1. Tidal energy provides a high-efficiency method of power generation.
Tidal energy offers us one of the most efficient ways to generate power in the world right now. The most recent installations that use this technology can achieve an efficiency rating above 80% consistently. The only resource that we currently use that is better than this comes from nuclear power, which achieves a 91% efficiency rating in the United States. When you compare this renewable resource to the fossil fuels that release greenhouse gas emissions and particulates to the atmosphere, it is over 30 percentage points higher.
When we compare tidal energy efficiency rates to other renewables like solar and wind, the difference is more than 50 percentage points.
2. The lifespan of a tidal energy resource is extensive.
Tidal energy facilities have the capability of operating for over 50 years with very little maintenance needed to continue functioning. This advantage means that communities can use the electricity generated by this engineering feat for twice as long as the average solar or wind installation. The length of service time is comparable to what a coal-fired power plant can offer, and it is similar to the initial expectations of what we would receive with a nuclear facility.
Revised lifespan estimates for nuclear power plants have taken the capability of that technology to almost a century of usefulness. There is nothing to suggest that tidal energy couldn’t achieve the same results.
3. The operational costs of a tidal energy facility are minimal.
Although the initial installation cost of a power plant that relies on the tides is comparatively high to other energy resources, a significant level of savings occurs over the lifespan of the facility. This form of electricity is one of the cheapest options that we have once you go beyond the first capital expenses. Some locations are already generating power at a rate of $0.02 per kilowatt-hour.
There isn’t another form of renewables on the market today that can match this cost profile, and many fossil fuel-based forms of power generation also struggle to keep pace with it.
4. Tidal energy is entirely renewable once the installation is complete.
We must pay an initial fossil fuel expense to create or manufacture the equipment necessary to generate electricity from a tidal installation. Once we get beyond this first down payment, the power we can generate with this technology is 100% renewable. We will always have access to the ocean, sunlight, gravity, and the moon. That means we can use this idea indefinitely to generate resources so that we can live a modern lifestyle while still having the opportunity to reduce our overall carbon footprint.
5. Power plants using tidal energy are environmentally friendly.
The benefits to the environment when using this option don’t stop at a better greenhouse gas emissions profile. It requires less space to operate than comparable facilities, has a reduced risk of impairing marine life than some methods of electricity generation, and eliminates the need for supplementary carbon and methane since fewer transportation needs are associated with this form of energy.
The typical installation that uses tidal energy can recoup the fossil fuel expenses to create its equipment within five years. Since the power generation equipment sits on or below the surface of the water, we also have more usable land for other needs thanks to this advantage.
6. Tidal energy provides a predictable power resource for communities.
Tidal energy provides a predictable form of renewable energy that only geothermal can match. We know when the tides move up and down because the tables can be calculated with tremendous accuracy. Although some movements can be stronger or weaker than expected, we always know when they’re going to happen. When using solar or wind energy, there can be high levels of uncertainty because of cloud cover, a lack of wind, or having the breeze be too strong for the turbines to manage.
Tidal energy doesn’t require us to use batteries to store power for overnight use. It is highly scalable so that we can meet peak demand levels with relative ease. That means it is easy to identify how much each facility can generate based on the equipment levels that engineers install.
7. It doesn’t take much movement from the tides to generate useful power levels.
Tidal energy allows us to start generating electricity with minimal water movement. Waves that move at three feet per second are sufficient for creating turbine motions at most installations. It is a significant advantage when compared to hydropower that often requires flows at over 20,000 feet per second to create results. That means a lower tide than expected will still generate enough water movement to create the power we need.
8. The impact on the environment is minimal for many tidal energy stations.
Although barrage systems can create extensive environmental issues, a tidal energy generator using a lagoon would have a minimal impact at best. We can construct facilities with natural materials, such as rocks, that would create breakwaters at low tide and be submerged at high tide. Animals would swim around this structure, and predators would be unable to break through the barriers in place. The energy output is low in comparison, but it would also give us the opportunity to create new estuaries where the ecosystem can thrive.
List of the Disadvantages of Tidal Energy and Power
1. Legal concerns exist regarding underwater land ownership.
Riparian rights are systems that allocate water among those who possess land along its path. It’s part of the common law heritage in Australia, Canada, and the eastern United States. A property that adjoins a body of water receives reasonable use of it as it flows over or through their land. Boating, fishing, swimming, and the right to wharf out to a point of navigability are all part of the reasonable use consideration.
Installing a tidal energy facility in large lakes could interfere with these rights. Legal questions also exist regarding who owns the land that lies underneath the water’s surface, or if there is a right to it at all.
2. Investors are not keen on supporting tidal energy right now.
Because tidal energy technologies are still in their infancy, investors are not as willing to put resources into this option since a return isn’t guaranteed. Engineers continue to work to improve the power generation capacity of this approach, and new installations can create significantly more electricity than the first stations that came online over four decades ago. Even with that progress, the lack of solid installation points and little long-term information makes many people leery of trying to expand the reach of this technology.
3. Installation points are few and far between for many countries.
The United States does not currently operate a tidal energy facility. Even when we look at the idea of an interior installation, such as what might be possible in one of the Great Lakes, the opportunities are few and far between for Americans to take advantage of this renewable energy resource. Even in the countries that operate facilities right now, only a handful of suitable installation points exist where electricity generation makes financial sense. There must be a lagoon, inlet, or similar structure available that provides consistent water movement in a confined area to maximize tidal flows.
4. Corrosion can be a significant issue for tidal energy facilities.
Even when this technology uses freshwater resources to generate electricity through title movements, a strong threat of corrosion exists. Most of the usable installation points for tidal energy exist near ocean coastlines. The increased levels of salt in the air place the equipment at a constant threat that exists above or below the surface of the water.
Although manufacturers give the equipment a rust-resistant coating to reduce the risk of this disadvantage, there is no guarantee that the low maintenance benefits of this technology will become available. All of the research that we currently have regarding this issue only looks at the situation through a short-term lens.
5. Tidal energy facilities can incur damage at almost any time.
Humans like to have access to a lot of space. As our population continues to grow, theoretically reaching over 10 billion individuals by the year 2100, we are going to need more land to manage our homes and businesses. People are naturally drawn to shorelines because of the natural beauty that exists when living by the water. That means more pressure on the ecosystem will occur over time, providing a potential source of damage to the equipment that generates electricity.
Even today, the threats of microplastics, human activities, and marine life all create problems that could lead to more maintenance issues. Warning signs don’t always act as a deterrent for human-based activities, and marine life could get swept into the paddles and collectors.
6. The equipment that generates power from tidal energy changes water flows.
When tidal energy facilities first come online, the environment works to adapt to the changing circumstances. One of the ways it accomplishes this result 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 generate freshwater from ocean tides, these facilities can decrease salt levels enough to cause injury to marine life in the area.
7. Tidal energy facilities don’t produce a lot of electricity.
Tidal energy plants cannot compete with the biggest hydro and nuclear facilities that currently operate in the world today. Small facilities like Itaipu Dam in Brazil have a total capacity of 14,000 MW. Several facilities in China, Canada, and South Korea can produce over 5,000 MW of power. The Sihwa Lake Tidal Power Station currently produces about 250 MW when operating at its full capacity. Since the expense profile of a new hydroelectric facility with a dam is comparable to that if a tidal energy solution, it is easy to see why most governments choose to go with a top producer.
8. The cost of a new tidal energy facility is massive.
Although private companies are trying to establish tidal energy facilities in Wales and South Korea, the initial investment to bring a power plant online that uses this technology is massive. The United States estimates that it would cost roughly $15 billion to add about 8,000 MW of capacity to the country’s infrastructure when using this approach to power generation. The Philippines is looking toward this solution to provide an additional 2,200 MW of capacity to their islands at an expense of roughly $3 billion.
Those same investments could go toward other forms of energy production that could triple the capacities listed in this disadvantage. Until we develop new approaches or efficiencies with tidal energy, the output capacities are minimal with this approach.
9. Habitat changes can occur with tidal energy installations.
The tidal energy facility located on the Rance River estuary in France uses a barrage to generate electricity. It came online in 1966, and it is still functioning. River currents combine with tidal energy from the English Channel to create a power resource. What we’ve learned since this facility came online is that increased levels of silt have entered wildlife habitats. This outcome has caused native aquatic plants to suffocate in the altered environment, and a flatfish is now extinct because of the installation.
The marine life dynamic also shifted because fish that thrive in heavy silt environments now love to call this area home. Cuttlefish are around in extreme numbers because of the cloudy waters.
10. Unknown consequences may occur after installing tidal energy facilities.
Although there are more than four decades of information to support the viability of tidal energy for power generation, we don’t have any long-term data to review. This technology is still in its infancy, so the impact it has on the environment is still somewhat unknown. We know that careful installation processes and safeguard installations can prevent marine life injury, but habitat changes can also create an imbalance in certain areas. It is entirely possible that we could find ourselves unintentionally hurting our planet as we try to help it.
11. Some equipment can disrupt the tides.
Placing a turbine in a tidal stream is a complex process. The machines can be exceptionally large, and that means they have the potential to disrupt the tide that is being harnessed to generate electricity. Since this option is most effective in shallow waters so that ships can steer around them, the resulting installation could change the way that the tide comes into the shore. The blades would also spin at speeds that could be dangerous to some forms of marine life.
Tidal energy provides us with another solution to review as we look for ways to reduce our dependencies on fossil fuels. The reliability of this resource, combined with its ability to distribute electricity through our existing infrastructure, gives us certain advantages that other renewables cannot provide with our current level of technology.
The issue that we may always have with this approach to energy production is the lack of geographic availability. Although this problem may slowly disappear as new, innovative technologies enter the market, it is a significant barrier to today’s electricity generation needs.
The advantages and disadvantages of tidal energy show that it is a highly efficient way to produce the power we need. It may become an effective way to reduce greenhouse gas emissions in the future. We must continue to develop new processes and approaches to take advantage of this potential resource.
Blog Post Author Credentials
Natalie Regoli, Esq. is the author of this post and the editor-in-chief of our blog. She received her B.A. in Economics from the University of Washington and her Masters in Law from The University of Texas School of Law. In addition to being a seasoned writer, Natalie has almost two decades of experience as a lawyer and banker. If you would like to contact Natalie, then go here to send her a message.