In this guide, we list the pros and cons of tidal energy.
This guide forms part of a series of guides we have put together outlining the benefits and disadvantages of different energy sources and energy generation methods.
Summary – Tidal Energy Pros & Cons
Is renewable (unlike fossil fuels which are finite)
There is no re-fuelling that needs to take place once tidal energy technology is set up (unlike coal plants for example)
May have significant potential for large scale power generation/supply
Tides can be a reliable and predictable source of power (more so than wind or the sun)
Can be effective at low water speeds
Life span of a tidal wave setup is relatively long – meaning the return on the initial investment increases with each year of operation
Doesn’t take up inland real estate
Is in early development – technology needs much more research and development to become more effective and established
Final impact on the environment in unclear
Limited by how close it needs to be constructed to shore
Can’t be used by a single individual (like for example a solar cell can be)
Not a portable energy source
Currently an expensive energy source for suppliers and consumers – is not yet profitable commercially without larger scales and better technology
More of a supplementary power source at this stage
Tidal energy is another potential form of a green, renewable energy source.
Like wave energy, it might have significant potential for future energy generation on large scales in the long term.
However, at this stage, there needs to be further development and technological advances before it become competitive commercially, and before it becomes feasible and effective on a large scale.
It appears to be much more of a prospective/speculative energy source at this stage compared to other already established energy sources.
*Note – the above pros and cons are broad generalisations
Obviously there are different variables to each specific energy project that impact the final pros and cons (like new technology that reduces emissions for coal power plants just as one of many examples).
Each energy project and situation (in different countries and cities) should be analysed individually.
Having said that, some broad principles and patterns about the pros and cons of different energy sources tend to stay consistent too.
What Is Tidal Energy
The most common form of tidal energy generation is the use of Tidal Stream Generators.
These use the kinetic energy of the ocean to power turbine – underwater turbines that look and act much like wind turbines.
Tidal barrages or more the more recent technology, dynamic tidal power (DTP) are also used.
– renewableresourcescoalition.org, and energyinformative.org
Tidal Energy Pros
It relies on ocean undercurrent and tides for power
High and low tides are a result of [mainly gravitational forces from the sun and moon, and also the Earth’s rotation]
Being that the Sun is estimated to be around for billions more years, it might be accurate to call tidal energy renewable
This is in comparison say to finite fossil fuels that have to be mined from the ground, such as coal for example
Is A Form Of Green Energy
Doesn’t produce any waste or greenhouse emissions during operation
This is unlike coal for example that produces carbon emissions, and produces waste like fly ash
This is a benefit for environmental issues like climate change just as one example
No Refuelling Required
Tidal energy doesn’t require refuelling like coal energy does for example
Significant Potential For Energy Generation
[A report] estimated that tidal energy could meet as much as 20% of the UK’s current electricity demands (openaccessgovernment.org)
The worldwide potential for tidal power is also estimated to be in the 100’s of Terrawatts a year
If in the future this energy potential can be realized, tidal energy would become an energy source capable of producing electricity at larger scales like other energy sources can, and this would make it a much more valuable energy source
Reliable and Predictable
Tidal currents are highly predictable, and reliable
High and low tide develop with well-known cycles, making it easier to construct the system with right dimensions, since we already know what kind of powers the equipment will be exposed to.
This is in comparison to more variable forms of energy for example
Effective At Low Water Speeds
According to some sources, water has 1000 times higher density than air, which makes it possible to generate electricity at low speeds
This adds to the flexibility, utility and potential of tidal energy
Lifespan Seems Long
The tidal barrage power plant La Rance was opened already in 1966 and still generates large amounts of electricity.
A long lifespan means the cost these power plants can sell their electricity at is ultimately reduced, making tidal energy more cost-competitive.
This can also be a good thing for investors, and it may also lead to other benefits such as not needing to wait on lead times for new constructions.
Doesn’t Take Up Inland Resources
Unlike solar panels or wind turbines for example, tidal doesn’t take up inner land resources.
Instead, it uses ocean space.
This could be an advantage for land scarce areas and cities, and places without suitable geographic locations to utilize other types of energy.
– energyinformative.org, and renewableresourcescoalition.org
Tidal Energy Cons
In Early Development, & Needs More Research & Development
Tidal power is early in the development stages.
It needs more research, development and investment to get a better idea of how effective it can be as an energy source.
Because of this, it is not able to compete with fossil fuels and other more established energy sources yet.
More Of A Supplementary Power Source Right Now
Can’t be used as primary energy source right now because it simply isn’t established or proven enough (amongst other reasons)
Environmental Impact Is Uncertain
Because tidal energy generators rely on ocean levels and current, there’s a possibility they may have similar effects to hydro-electric generators which can impact the ecosystem around them.
Technological solutions that will resolve some of these issues are currently being developed.
Either way, there may not yet be a consensus on their environmental impact.
Currently Need To Be Constructed Closer To Shore
Onshore construction is required as opposed to offshore tidal systems.
In the future, there might be a preference to exploit weaker tidal currents, at locations further out in the sea.
Technological advancements are being worked on in this regard.
But, overall, this is a potential limitation.
Currently Expensive For Suppliers & Consumers
It is projected that tidal power will be commercially profitable by 2020 with better technology and larger scales.
But, this is speculative, and even then, the technology and scale will be limited in some ways.
Until cost and price become competitive with other energy sources, this is another limitation.
Not For Individual Use
Can’t be used individually for households, like solar can be for example.
Can’t be used as a small, portable power source, like small solar panels can be for example