Tidal power uses the kinetic energy of the tides to generate power. This process has a number of advantages and disadvantages associated with it. In this article, we explore the different pros and cons of tidal energy.
Tidal Energy Pros
Let’s start by looking at the different advantages of tidal energy.
1. Tidal Power is Environmentally Friendly
Tidal energy is an environmentally friendly alternative to fossil fuels. When we produce electricity from the tides, we produce zero carbon emissions. These are not only bad for our health but are also a key component of global warming.
As we source more of our energy from renewables, we help to improve the quality of the air we breathe. In addition, by reducing greenhouse gas emissions, we are helping to reduce the future effects of climate change.
2. It’s Both Renewable & Sustainable
Tidal energy is renewable, meaning we can use it again and again without it running out. Unlike non-renewable alternatives (such as coal, oil, and natural gas), we can always rely on the tides as a source of energy. The sustainable nature of tidal energy makes it a wise investment in helping to meet future energy requirements.
3. The Tides Are Reliable
The tides run like clockwork. We can rely on them to rise and fall throughout the course of the day. This makes tidal energy a very reliable and predictable energy source. It is even more predictable than wind and solar energy.
4. Tidal Energy is Efficient
Tidal energy is extremely efficient. Water has a density of around 1000 times greater than that of air. This allows tidal turbines to be effective at low water speeds, unlike wind turbines which require significant wind speeds.
5. It Has Low Running Costs
Ignoring construction costs, tidal power plants have very low running costs. Tidal turbines require infrequent maintenance, as do tidal barrages. Whilst maintenance can be an expensive process, there is usually a large gap between maintenance intervals.
6. Tidal Barrages Can Have Multiple Uses
A tidal barrage involves the construction of a dam-like wall to hold back seawater. Structures like these can be used for other purposes. For example, a barrage can be used as a road or footbridge, avoiding the need to build a separate structure. Tidal barrages can even double up as a flood barrier to help protect inland areas from flooding.
Tidal Energy Cons
Next, we’ll look at the various disadvantages that tidal energy has.
1. Tidal Barrages Impact The Environment
One of the bad things about tidal energy is that tidal barrages have a number of environmental effects. Many of these are similar to the environmental impacts of hydroelectric dams.
2. Tidal Turbines Can Harm Marine Life
Just like wind turbines kill birds, tidal turbines have the potential to harm marine life. Whilst tidal turbines spin much slower than wind turbines, they can still post a threat to fish and other marine life.
3. Barrages Can Disrupt Migratory Patterns
Tidal barrages have similar disadvantages to hydroelectric dams. One of these is that they can disrupt the migratory pattern of fish and other marine life. Some marine fish make their way up estuaries to spawn. Some species of fish living in estuaries migrate in the opposite direction (to the sea) in order to spawn.
4. Tidal Energy Can Restrict Access To The Sea
Both tidal turbines and tidal barrages can restrict access to open waters. This can have an effect on those who rely on unrestricted access to the sea. Fishermen, transport companies, and recreational sea goers are all affected by the presence of tidal energy plants. Some species of marine life can also be affected, especially where tidal barrages are concerned.
5. Tides Are Intermittent
Coastal areas experience two high and two low tides every 24 hours and 50 minutes (a lunar day). With the tides being intermittent, tidal turbines are unable to operate 24 hours a day.
It does, however, take six hours and 12.5 minutes for the water at the shore to go from high to low (or from low to high) tide. Whilst tidal turbines are only viable during part of this cycle, there is still a lengthy window where they can operate.
It is here where tidal barrages have a huge advantage over coastal tidal turbines. Barrages hold back water, acting in a similar way to that of a hydroelectric dam. Engineers can then release this water on demand to generate power as and when it is needed.
6. Tidal Energy is Location Specific
Tidal energy is one of the most location-specific renewable energy sources. Unlike solar and wind energy, tidal energy is only available at coastal areas and estuaries. It is therefore useless to landlocked countries.
To make matters worse, not all coastal areas are suitable for tidal power. According to the Ocean Energy Council, a tidal range of at least 7 meters is required for the economical operation of tidal turbines.
7. Tidal Power Plants Are Expensive To Build
It’s no secret that marine construction and coastal engineering projects are expensive. Large projects such as the construction of tidal barrages can cost in excess of $1 billion.
Whilst construction costs may be offset by the income a tidal power plant generates, such projects still require a significant upfront investment. This can sometimes be beyond the reach of less economically developed countries.
8. Maintenance of Tidal Turbines is Difficult
Tidal turbines can be difficult to maintain. When maintenance is due, engineers need to raise the turbines from the seabed. This is a complex procedure requiring specialist knowledge and equipment.
Luckily, most tidal turbines are designed so they require infrequent maintenance. SIMEC Atlantis Energy design their turbines to last for around six years between maintenance intervals.
So, there we have our list of tidal energy pros and cons. You can see from the points raised that there are valid arguments both for and against the use of tidal power.
On the one hand, tidal energy has numerous environmental and ecological drawbacks, it is expensive, and difficult to maintain. But, on the other hand, it is capable of generating clean and renewable electricity to help meet future energy demands.