Ryan, Saad, Sufie Energy Resources Assignment SPH 3U Tidal Energy Ryan, Saad, Sufie Energy Resources Assignment SPH 3U

What is Tidal Energy? A type of hydropower that is used to generate electricity by converting the energy of tides into usable energy. Tidal energy is a type of hydropower that is used to generate electricity by converting the energy of tides into usable energy, mainly electricity. There are multiple methods of collecting this tidal energy, some of which haven’t been attempted in the real world. Hydroelectricity is the most widely used form of renewable energy, and makes 16 percent of our global electricity generation.

Tidal Stream Generators (TSGs) Tidal Stream Generators make use of the kinetic energy of moving currents to turn turbines and power generators. The amount of power generated by TSGs is dependent on the strength of the water current. Tidal Stream Generators make use of the kinetic energy of moving currents to turn turbines and power generators. The amount of power generated by TSGs is dependent on the strength of the water current, so it varies slightly. TSGs can also be built existing bridges and other structures, practically invisible.

TSGs - Advantages Constant streams of water currents allow a constant generation of electricity. Highly efficient; TSGs convert about 80% of the kinetic energy of the water into electricity. Tidal Stream Generators are constantly generating electricity because they are built in strong water currents. While they are constantly generating electricity, TSGs are also being highly efficient; they convert about 80% of the kinetic energy of the currents into electricity.

TSGs - Disadvantages Difficult to install and maintain the underwater turbines. Changes in tidal movement reduces efficiency. Devices sometimes break down because of excessively strong water currents and sea water corrosion. Floor mounting may disrupt habitats of sea life. The underwater turbines in TSGs are difficult to install and maintain. The devices sometimes break down because of strong water currents and seawater corrosion. Also, changes in tidal movements reduce the efficiency of the devices in the water slightly. Finally, the floor mounting of TSGs may disrupt habitats of sea life.

Types of TSGs Horizontal Axis Turbines Vertical Axis Turbines Reciprocating Devices Venturi Effect Tidal Stream Devices Horizontal axis turbines are devices that have blades that rotate on a horizontal axis, while vertical axis turbine blades rotate on a vertical axis. There are multiple different reciprocating devices that all produce similar amounts of electricity. Venturi Effect TSGs involve the use of a funnel-like water turbine.

Tidal Barrages Dams that use the raising and receding tides and the potential energy involved. When the tides rise, water flows from the sea into the basin of water that the dam is holding back. When the tides recede, the water is released through gates of turbines, which power generators. Tidal barrages are dams across rivers and oceans that have gates and turbines to control the movement of the tides. When the tides rise, the water flows into the dammed area. Once the tides switch directions the gates open and water flows through the hydroelectric turbines producing electricity.

Tidal Barrages - Advantages The tides are predictable because of the relation to the moon, thus making it a reliable source of renewable energy. Barrages are not dependent on random weather patterns, unlike wind or solar energy. It is a cheap energy source once the initial cost is paid off. Tidal barrage is a reliable source of renewable energy because the tides are predictable do to the connection to the moon. Barrages do not depend on the weather conditions like wind and solar energy do. Also It is a cheap energy source after initial cost is paid off.

Tidal Barrages - Disadvantages Fish and other marine life can be hurt or even killed by colliding into or going through the turbines; their movements or migrations could also be affected. Limited suitable locations, needs good sized tides and large areas for the dam and the water retainment The disadvantages of tidal barrages are that they can injure or kill fishes and other marine lives by them colliding into the rotating turbines. Tidal barrages are constructed in suitable location. These locations need good sized tides and a large area so the dam can fit.

Types of Tidal Barrages Ebb Generation Flood Generation Two-Way Generation Double Basin Tidal Generation There are 4 types of tidal barrages, ebb generation occurs when the basin is filled through gates until high tides and flood generation occurs when the basin is emptied through the gates and turbines generate at tide flood. Two way generation happens when the tides Ebbs and floods. Double basin is two basin, one is filled at high tide and other is emptied at low tide.

Dynamic Tidal Power (DTP) An untried, proposed technology which involves building long wall-like dams straight out from the coasts of specific areas. As waves hit the dams, strong coastal-parallel currents are created and can be captured and transformed into electricity through generators. This system is just a theory, but has promising technology. Basically, DTP involves a T-shaped dam, with at least 30 km coast-parallel (yellow in the graph) and bidirectional turbines. Blue represents low water and red represents high water. The differences in height allow the turbines to spin and generate power.

DTP - Advantages A single dam can produce 8 to 15 gigawatts (8 to 15 billion watts) in an hour. Very stable compared to other methods. High availability, only requires a wide coast. Potential for combined functions, such as with coastal protection. The main advantage of DTP is that a single installation can produce 8 to 15 gigawatts of power, the highest among all kinds of tidal energy. Secondly, it is stable because it continues generating no matter which direction the tide is moving. Also, it is highly predictable and available, and it also has various of beneficial combined functions.

DTP - Disadvantages Unsure if the technology involved will be efficient or even successful, since it is not currently in use. Can only be tested on a large scale, which could be expensive. There is potential to negatively affect the environment and the ecosystem. First of all this method is untested, therefore unsure about the effectiveness. Secondly the cost will be expensive with building a 30 km dam. Finally, the environmental impact of DTP is uncertain, there may be potential negative effects on marine’s living pattern such as changing in mating pattern, migration pattern and so on.

Tidal Lagoons Tidal Lagoons are a newer design concept, involves building circular wall-dams that retain water, capture potential energy of the tides, and transform it into electricity using turbines and generators. Similar to Tidal Barrages, but artificial location and no pre-existing ecosystem. Tidal Lagoons are a newer design concept, which started planning very recently. The idea of tidal lagoons involves building circular wall-like dams that retain water, capture the potential energy of the tides, and transform it into electricity using turbines and generators. The concept is similar to tidal barrages.

Tidal Lagoons - Advantages Tidal Lagoons are reliable because of constant electricity generation and predictability. Easy to combine with special pumps that use renewable energy to raise water levels, increasing energy production. Dam could support potential local sports, such as walking, cycling and swimming. Tidal Lagoons are reliable because of their constant electricity generation and high predictability. Lagoons would be easy to combine with special pumps that use renewable energy to raise water levels and increase energy production. Also, the dam could support potential local sports, such as walking, cycling and swimming.

Tidal Lagoons - Disadvantages Higher cost due to large size and amount of resources needed. Do not capture as much as water as the other methods, individually they create less energy. Energy generation is significantly lower than other technology, such as wind- or tidal stream- generated. Tidal lagoons have a higher cost due to the large size, and the amount of resources needed. They do not capture as much as water as the other methods. Individually, they create less energy; their energy generation is significantly lower than other technology, such as wind- or tidal stream-generated.

Application of Methods Tidal Barrage; Rance Tidal Power Station in France, opened 1966 (World first and largest tidal power station until the one in Korea is installed). Stream Generator; Seagen in Strangford Lough in the U.K. Tidal Lagoon; Swansea Bay Project construction is scheduled for completion in U.K. by 2017 The actual application of the three methods are the world first tidal station-- Rance Tidal Power Station in France using tidal barrage. Stream generator method is applied in Seagen in the U.K. Tidal lagoon method is applied in the Swansea Bay Project which is scheduled to be completed by 2017.

Tidal Energy Vs. Wind Energy Tidal energy costs more to operate and construct the machines than wind energy. Wind energy is unpredictable due to unstable weather conditions; tidal energy is completely predictable. Water turbines produce much more electricity than wind turbines; Water turbines produce an average of 1,824,000 kWh per day, wind turbines produce an average of 14400 kWh per day. Wind turbines create noise for people living nearby, and may harm birds and other wildlife. The difference between tidal energy and wind energy are that tidal energy machines have a higher constructional and operational cost. Water turbines produce much more electricity that wind, also wind energy is unpredictable do to the unstable weather conditions. Wind turbines create noise and can harm birds and other wildlife.

Tidal Energy Vs. Solar Energy Initial cost of solar energy panels are cheaper than tidal energy devices. Weather patterns directly affect the efficiency of solar energy since solar panels depend solely on sunlight. Tidal energy produces more electricity, constantly. Solar panels require space on land to be built: the amount of space depends on the amount of panels. Solar energy produces pollution, Nitrogen trifluoride and sulfur hexafluoride… these greenhouse gases have an impact on global warming; tidal energy is pollution free. Tidal energy is much more efficient than solar energy because solar panels produce electricity for half of the day do to the sun. Solar panels has a lower initials cost than tidal energy devices. Solar energy produces greenhouse gases that have an impact on global warming.

Monetary Cost of Building a Tidal Project Construction cost There is a high capital cost for a tidal project, with a 5 to 7 year construction. Meanwhile, the high cost of engineering design, using large manpower. The cost of one tidal turbine that converts 65 kw of power costs $4,000,000. However, at the same time, it introduces job opportunities to complete construction which is good for the economy. Maintenance A minimum lifespan of 120 years is estimated by engineers. The construction cost of building a tidal project is fairly high, but it has a long lifespan with a minimum of 120 years. A time of 5-7 years of construction is required, meanwhile, a large amount of money is spending on design, manpower, engineering and so on. One tidal turbine costs about 4 million dollars.

Environmental Impacts A mortality of rate of fishes passing through a tidal barrage is 20% -80%. Holding back the tide allows silt to build up in the river bed, reducing the water flow for years! Disrupted fish migrate; may reduce the fish population in the oceans. The noise pollution produced by the turbines. There are many kinds of environmental impacts due to installing a tidal project. The tidal blades are possible to kill the swimming sea life like fishes. Noise pollution is produced by the turbines that causes marines to leave that sea area. Also, holding back the tide can cause silt to build up the river bed and reduces water flow over a number of years!

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