How Efficient is Tidal Energy? Things To Know

How Efficient is Tidal Energy? Things To Know

Read and learn how efficient is tidal energy and what challenges tidal energy is facing.

Waves and tides offer some of the most predictable, consistent, and just generally big energy resources available. Do you know how effective tidal energy is, though? In comparison to coal and oil, which only convert 30% of the energy contained therein, tidal power produces electricity using about 80% of the kinetic energy.

You can find out more about the effectiveness of tidal energy by reading this blog.

How Efficient is Tidal Energy?

Tidal energy systems have the potential to be very effective. According to engineering firm N-Sci, tidal turbines convert 80% of the energy of the tides into electricity. This is considerably more effective than coal, oil, or natural gas, as well as current wind or solar energy systems.

Power plants only release 30% to 45% of the energy contained in these fossil fuels, according to the Energy Information Administration.

Is Tidal Power Renewable and Sustainable?

Tidal energy is renewable because it doesn’t depend on any resources that can be used up. The tide will keep coming in and going out every day for as long as there is a moon in the sky.

How Efficient is Tidal Energy? Things To Know

Because it doesn’t pollute, tidal energy is also environmentally friendly and sustainable. Producing and maintaining the turbines is the only carbon-intensive part of tidal power generation.

The absence of environmental issues, however, does not follow from tidal power. As discussed below, tidal turbines can harm marine ecosystems in a variety of ways. One of the main obstacles to expanding the use of tidal energy is minimizing the harm done to marine life.

Why Isn’t Tidal Power More Common?

“The fundamental question is one of economics,” says the University of Washington Associate Professor of Mechanical Engineering and Director of the Pacific Marine Energy Center Brian Polagye Tidal power is an expensive source of energy due to the early stage of the technology: a 2019 study estimates that commercial-scale tidal energy costs between $130 and 280 per megawatt-hour, compared to $20 per megawatt-hour for wind. This is because tidal energy is still in its infancy as a source of energy.

High upfront costs of building plants, expenses associated with maintaining machinery that can survive corrosive seawater, and the pricey engineering work that goes into them make up a significant portion of that cost discrepancy. Polagye adds that the supply chain for tidal power also isn’t yet capable of providing the necessary components and technologies at scale to make this energy source and, as of now, “everything’s pretty custom.”

In fact, the market discrepancy between tidal and other, more mature, renewable energy systems is actually growing because the cost of generation from wind and solar generation continues to drop. Beyond the economic difficulties, the tidal power industry also must overcome technical challenges such as the lack of an established and routine production market and legislative red tape.

The environmental impact is a further consideration, the extent of which is still not fully known. Tidal barrages can kill off plants and animals, alter salinity and sediment levels, and cause havoc with coastal ecology, depending on the size and design of the system. Researchers like Polagye are trying to figure out how to harness tidal currents with much less environmental impact. “We’re learning from our mistakes and trying to identify problems and stress mitigation proactively before they occur,” he says.

How Efficient is Tidal Energy? Things To Know

Benefits of Tidal Power

As a source of renewable energy, tidal energy has a lot of potentials. Tidal power systems are:


Air is over 800 times less dense than water. In comparison to an equally fast stream of air, a stream of water has a much higher energy content. A water turbine can generate significantly more power than a wind turbine of the same size operating at the same speed. (But for the reasons covered in the paragraphs below, tidal turbines can’t really be this large.)


A tidal turbine produces no pollution once it is operational. Specifically, it doesn’t emit greenhouse gases that contribute to climate change.


Tidal power is a renewable energy source. Except for the production, installation, and maintenance of the turbines, it does not require any natural resources.


Long-lasting tidal turbines. According to the British power company SIMEC Atlantis Energy, a turbine can run for 25 years and only needs maintenance every 5 years. That keeps operating costs low.


Unlike wind, tidal energy is predictable and stable. It can offer a consistent supply of energy, which is necessary to maintain the grid’s efficiency.


Offshore wind plants often attract complaints from people who think they spoil the landscape. This issue is not brought on by tidal turbines, which are typically underwater and invisible from the shore.

Challenges Facing Tidal Power

How Efficient is Tidal Energy? Things To Know

Despite the benefits of tidal power, it hasn’t gained widespread acceptance. Scaling up is difficult due to a number of significant issues and difficulties. These include:


Although the weight of the water increases its energy, it also puts a great deal more strain on the turbines. To resist pressure, they must possess exceptional strength. And they generally can’t be as big as wind turbines, which means it takes more of them to produce enough power.

Tidal power systems must also be constructed underwater. Additionally, most need cables buried beneath the surface to connect to the grid. They are therefore challenging to install and maintain.

All of this comes at a high price. According to a Clean Technica analysis from 2020, the cost of electricity from a proposed tidal lagoon in Britain would probably be around 20 cents per kilowatt-hour. That’s roughly ten times the cost of wind power.

Scientists might figure out how to make tidal power systems less expensive, produce more energy from them, or both. But until they do, it will be hard to make them cost-effective.


The tide’s strength changes over time even though it is constant and predictable. Only about 10 hours of the day can be powered by it. And those 10 hours don’t always meet up with the hours of highest demand for electricity.

There are two ways to eliminate this power supply jerkiness. One is to construct tidal energy storage systems. The second is to construct tidal plants in numerous locations so that the tide is consistently high at some of them. But both solutions add further to the cost.


How Efficient is Tidal Energy? Things To Know

Only coastlines can accommodate tidal power systems, and not all coastal locations are suitable. You require a strong water flow in order to harness tidal energy. For that, either there must be a significant drop in water level from high tide to low tide, or there must be a narrow channel where the force of the water is concentrated.

There are a limited number of sites that meet these requirements. Moreover, the ones that exist aren’t always near existing power lines, so hooking them up adds to the cost.


In a number of different ways, tidal turbines can damage marine ecosystems. They can also catch aquatic life in their blades, obstructing their movement. They have the ability to alter the water’s salinity and silt content.

Communication among marine life may be hampered by the noise that underwater turbines make. Even the electromagnetic fields from power lines might have an impact on delicate species, making them stay away from the area. And restricting the movement of fish reduces the food supply for marine birds, which might also relocate as a result.

Future Outlook of Tidal Energy

In some nations, tidal energy is thriving. In Scotland, a 600-ton turbine anchored right off of the Orkney Islands is already generating power. For the next 15 years, it is anticipated that the O2 turbine will supply all of the energy needs for 2,000 homes.

A new set of incentives supporting tidal energy was recently introduced in the UK. The tide may also turn in the US: last year, the Department of Energy announced a $27 million investment in research and development around tidal and wave energy technology.

In the United States, it is unlikely that tidal power will ever be a significant source of energy. We have a few locations where we could harness tidal energy at a reasonable cost. Other nations, such as China, France, Russia, and the U.K., are in a better position to take advantage of tidal energy’s potential.

Conclusion: the Efficiency of Tidal Energy

The efficiency of tidal energy in converting water’s potential energy into electricity is 80%. A long-term source of electricity is tidal power. If constructed, a proposal for the Severn Barrage is expected to reduce annual coal consumption by 18 million tons. Consequently, less greenhouse gas is released into the atmosphere.


Why is Tidal Power Inefficient?

Tidal power is a promising renewable energy source, but production costs, a limited number of suitable locations, and technological challenges hinder its expansion.

Is Using Tidal Energy Effective?

Tidal energy is stronger than wind because water is hundreds of times denser than air. It is more efficient than wind or solar energy due to its relative density and produces no greenhouse gases or other waste, making it an attractive renewable energy source to pursue.

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