The world is facing turmoil with the population expected to increase to 9.7 billion by 2050. The world is also faced with the depletion of natural resources and fossil fuels, land scarcity, and on top of all that climate change.
Furthermore, with advancements in technology and the increase of electronic devices, there is an increase in electricity demand. Hence, alternative sources of energy are needed to cope with demand.
There are a lot of innovations taking place around the world to take advantage of renewable resources such as wind, solar, geothermal, hydropower, etc… however, there is a renewable resource that is not getting enough attention and this is energy from the tide.
Tidal energy is a form of hydropower that converts the natural rise and fall of tides into useful forms of power such as electricity. Tides are created by the gravitational interaction between the moon and the sun which causes cyclical movement of the seas on earth.
Tides is an infinite source of energy as compared to non-renewable one. They are also predictable, they come in, they go out and it’s been doing that for a long time. The energy from tides and currents represents a massive resource just waiting to be tapped.
With free-flowing power, there is no need to rely on building massive dams and wind turbines that disrupt the environment. Turbines are put into water without affecting anything around. They sit on the seafloor and harness the energy of moving water that comes in and goes out.
If suitable ways to harass the power of the tides and waves off the coasts are found at large scales, it could provide the final push needed to convert grid to 100% renewable. The potential is huge.
It is estimated that tidal power could practically capture enough energy to power all homes in the United States twice over. Yet, at the moment all the electricity produced from existing tidal power plants worldwide can only power about 400 000 homes.
So why tidal power work is getting lots of attention?
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Why tidal energy is gaining importance?
As worldwide demand for clean and renewable electricity continues to grow, it is crucial to identify and secure sustainable resources beyond what is currently available. Researchers recognize the vast potential of the ocean to produce renewable energy.
Harnessing the power from the tide over other forms of renewable sources is an entirely predictable process. Also as water is denser than air, tides are more powerful than wind energy. It can produce more power with the same turbine diameter and rotor speed.
Tidal power is also more consistent than wind or solar energy. As wind and sun are intermittent and less predictable. This makes it an intriguing renewable source to pursue.
Tidal energy represents an opportunity to increase the world’s power-generating capacity. And with climate change, there is pressure for electricity systems to be more sustainable and provide additional clean energy.
It can provide a renewable source of electricity without emitting any gases responsible for global warming. And could also decrease the need for nuclear and fossil fuels to generate energy as they are associated with radiation risks and acid rain respectively.
Ways tidal power is harness
Turbines can be installed in places where there is strong tidal activity. Blades are used through turbines to turn a rotor that powers a generator. Turbines placed in tidal streams capture energy from the flow of water and underwater cables transmit it to the grid. There are currently three ways of harnessing tidal energy:
- Tidal streams
- Barrages
- Tidal lagoons
Tidal streams
The tidal stream is fast-flowing water created by tides. The power is generated using turbines that are placed in tidal streams. A turbine is a machine that takes energy produced from a flow of fluid by tides.
Since the flow of fluid can have a combination of air or water. The water is much denser, hence more powerful. Tidal energy generators and turbines are placed in the streams. The turbine swallows the energy created from the flow of fluid and converts it to electricity with the use of tidal generators.
Barrage
Tidal energy generated using a dam is called barrage. Hence tides water spills over the top or through turbines in the dam. Turbines inside the barrage harness the power of tides the same way a river dam harnesses the power of a river.
The barrage holds the water when the tide rises to create a pool. The water is then released through the barrage’s turbines when the tide is low, creating energy at a rate that can be controlled by engineers.
However, the environmental impact of the barrage system is quite significant. The land in the tidal range is completely disrupted. The level of the tidal lagoon might harm plant and animal life.
Fish are blocked into or out of the tidal lagoon and when the turbines move, marine animals can be caught in the blades. It can also limit food sources for birds which might force them to migrate elsewhere. The barrage system is much more expensive as it involves big construction and more machines.
Tidal lagoon
This tides energy generator involves the construction of tidal lagoons. A tidal lagoon is a body of ocean water that is partly enclosed by a natural or manmade barrier. It functions much like a barrage however, it can be constructed along the natural coastline.
A tidal lagoon power plant could also generate continuous power. Its environmental impact is reduced drastically as compared to the barrage system. The lagoons can be constructed with fewer materials. It can also use natural materials like rock.
The structure appears as a low sea wall at low tide and is submerged at high tide. Animals could swim around the structure. However, the energy output from generators produce by the lagoon is significantly low.
Impact of tidal energy
Tidal power is a clean, renewable, sustainable resource that represents a significant opportunity to meet growing global electricity needs for now and the future. Water is denser than air which makes this source a powerful one.
It is more efficient than wind or solar energy as it is relatively predictable and produces reliable continuous flow. Low tide and high tide are easily predicted as they rarely experience unexpected changes.
It also produces no greenhouse gases or other waste making it a renewable energy source to pursue.
Here are some beneficial impacts of tidal energy:
Environmentally friendly
Tidal is a clean source and doesn’t release any greenhouse gasses into the atmosphere. Since the system is installed on the coastlines and offshore, it is good for the environment as lands are not affected.
Renewable energy source
Like other forms of renewable sources, using tides to generate electricity won’t run out as long as there is the sun and the moon. Tide is an infinite source of energy.
Predictability
Tides happen at the same time and regularity that can be predicted in advance. It is a well-understood cycle that makes it easier to develop tidal energy systems. And the level of power the system will be exposed to is highly predictable.
Cost-competitive
Once a tidal power plant is constructed, it has the potential to generate electricity for many years. Although the upfront costs of constructing the plant are high, the return on investment will be realized in the long run.
It can be more effective than wind energy
Tides produce more power than wind since ocean water is 832 times denser than air. This means tidal current applies more force on the turbines which generate more energy.
Examples of tidal power plant
LaRance Tidal Power Station, France
The world’s first tidal barrage was built between 1961 and 1966. It is currently the world’s second-biggest renewable tides power plant operated by Électricité de France (EDF). It has an annual generation capacity of 540GWh and serves the needs of around 130,000 households every year.
Sihwa Lake Tidal Power Station, South Korea
The world’s biggest tidal power plant was built in 2011 with an installed capacity of 254MW. The project is owned by Korea Water Resources Corporation. Its annual generating capacity is 552.7GWh. It allowed South Korea to reduce its CO2 emissions by more than 300,000 tonnes each year.
Annapolis Royal Generating Station, Canada
Annapolis Royal Generating station has a capacity of 20MW which makes it the world’s third-biggest operating tidal power plant. It generates 50GWh annually which powers over 4,000 homes.
Jiangxia Tidal Power Station, China
It is the fourth-largest tidal power station in the world. Its capacity is 3,200 kW and generates up to 6.5 GWh of power annually. The power station feeds energy demand for small villages in its proximity through transmission lines.
Swansea Bay Tidal Lagoon, South West Wales, UK
Swansea Bay Tidal Lagoon project is the world’s biggest tidal lagoon power project and will become the world’s third-biggest power plant when complete. It will be able to generate electricity for 155,000 homes for the next 120 years.
Future of tidal energy
Despite the advantages, countries have been slower to invest in tide electricity generation systems than other renewable resource projects. The industry poses some challenges such as the initial setup costs being considered expensive when compared with other energy sources.
Hence making it difficult to get investments and funding. It is also difficult for private investors to generate a profit in short term this is why so far, projects have only been conducted by governments.
The Environment can be harsh for technologies as saltwater can cause a lot of maintenance issues. There is also ocean plant and animal that could interfere with devices which can potentially cause damage.
The robustness of devices, environmental challenges, and cost-efficient for a commercial application are barriers that need to be overcome to exploit this free-flowing power.
Thus, to realize the benefits of tidal energy on a commercial scale, it will be important to identify new technologies and methods that can significantly lower installation and maintenance costs and reduce environmental effects.
There are various countries such as Scotland, France, Japan, Korea, China, Canada and the United States are bringing forward new and improved technologies that show some potential.
These technologies can help clear all barriers to the commercial viability of tidal power and can be critical to the sustainable industry. The industry is largely just emerging, with complex barriers to overcome before it can sustainably grow and thrive.
There are definite opportunities associated with this source that could offer solutions to combat the world’s climate crisis. The potential power that could be generated from tides on a global scale is enormous.
A report published by BBC states that tidal power is severely underestimated. New technology and a more systematic understanding of tidal streams have put the concept in a more promising position.
It could become one of the most reliable forms of renewable energy. Even more reliable than wind power. Right now, it’s difficult for tidal power to compete with traditional electric companies which offer energy sourcing from coal, oil and natural gas.
However, the future looks brighter than ever before as costs are coming down. More scientists’ are showing interest in more efficient underwater turbines and power generators are finding ways to preserve biodiversity.
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