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NexPlan Recycling & Renewable Energy
Tidal Power & Wave Power:
The flowing waters in the rivers and oceans and tidal waves can be a good source of alternative energy. Tidal power, sometimes referred to as tidal energy, is a type of hydropower that uses the movement of water caused by tidal currents or the rise and fall of sea levels due to the tides. Although not widely used yet, tidal power has potential for future electricity generation. It is a type of renewable energy that is more predictable than solar power and wind energy. Tidal power has great potential for future electricity and power generation because of the massive size of our oceans.
Tidal energy is produced through the use of tidal energy generators. These large underwater turbines are placed in areas with high tidal movements, and are designed to capture the kinetic motion of the ebbing and surging of ocean tides in order to produce electricity. With close to seventy percent of the earth's surface covered by water, a vast amount of energy can be produced by placing turbines at strategic locations under strong currents. This method of generating electric power is called hydrokinetic power generation.
Wave power is similar to tidal energy. Wave power refers to the energy of ocean surface waves and the capture of that energy to generate electricity and the pumping of water into reservoirs. Wave power is a form of renewable energy. Wave power generation is not a widely employed technology, and no commercial wave farm has yet been established.
If you have ever lived near the ocean, you know about tides. With consistency, the tide rolls in and out moving vast amounts of water back and forth. This massive movement of water also happens to contain a huge amount of energy. If the power of the tides could be converted to usable energy, tidal energy would be part of the answer to many of the energy problems in the world. There are three basic ways to tap the ocean for its energy. We can use the ocean's waves, we can use the ocean's high and low tides, or we can use temperature differences in the water.
Tidal Power Generation:
Tidal power can be harnessed using a barrage or dam built across an estuary that captures the potential energy generated by the change in height between high and low tides. As the tide goes in and out, the water flows through tunnels in the dam. The ebb and flow of tides are used to either turn a water turbine or compress air through a pipe that then turns a turbine, which generates electricity. Tidal fences and turbines can also be used to capture tidal power. Tidal fences are turbines that operate like giant turnstiles, while tidal turbines are similar to wind turbines. In both cases, electricity is generated when the turbines are turned by the tidal currents that occur in coastal waters. Ocean currents generate relatively more energy than wind energy because ocean water has a higher density than air and thus applies greater force on the turbines. Tidal energy involves converting the power of the horizontal movement of the water into electricity and producing energy from the rise and drop of water levels. With our vast knowledge of hydroelectricity production with dams, converting moving water is currently the preferred technology. One approach absorbs the principals of dams in hydroelectric production. The idea is to let water come in when the tide is rising and then prevent it from leaving when the tide goes out. Doors are used to cut off the water. The water is then diverted into pipes with turbines and you basically have hydroelectric power.
Tidal energy is produced through the use of tidal energy generators. These large underwater turbines are placed in areas with high tidal movements, and are designed to capture the kinetic motion of the ebbing and surging of ocean tides in order to produce electricity. The uses of tidal dams or ocean currents are basically two methodologies for creating tidal power. In the context of ocean energy, barrage based tidal power is not considered a truly sustainable resource. The difference between the tide mill and today's tidal power plant is the size of the unit and the amount of energy generated.
Tidal power does however have great potential for future power and electricity generation because of the massive size of the oceans and the initiatives for cleaner energy sources.
Ocean thermal energy is another idea that uses temperature differences in the ocean. Power plants can be built that use this difference in temperature to make energy. A difference of at least 38 degrees Fahrenheit (20 Celsius) is needed between the warmer surface water and the colder deep ocean water. This type of energy source is called "Ocean Thermal Energy Conversion" or OTEC. It is being used in both Japan and in Hawaii in some demonstration projects.
Tidal Power Companies:
Tidal power companies are taking advantage of the rising interest in this alternative energy source. Large amounts of coastal waters are being reserved on the coasts of North America, Europe and Asia by companies who plan to take advantage of ocean energy technologies, in the hopes that these sites will become profitable sources of electricity.
New Brunswick and Nova Scotia in Canada along the Bay of Fundy, which has the highest tides in the world and is starting to get some attention in regards to developing tidal power. The Bay of Fundy has the best potential for tidal energy of sites that have been studied in North America and may even be the best site in the world. Nova Scotia Power owns and operates one of three tidal power plants in the world and the only one in the western hemisphere. They are involved in a new study on tidal power that could see underwater turbines installed in the Bay of Fundy and in waters off five U.S. states. Nova Scotia Power wants back into the bay with another pilot project and the latest in tidal power technology, the forerunner to what it hopes will be an authentic tidal farm of underwater sea turbines. New technologies are being created to capture the power of the tides, including the use of offshore floating tidal turbines and turbines that are anchored to the ocean floor.
In New York, tidal turbines are being submerged in the East River to generate electricity from rapid tidal currents. Verdant Power is a maker and installer of tidal power and hydroelectric systems. Verdant Power is installing six of these underwater turbines in New York's East River. The project involves a set of six submerged turbines that are designed to capture energy from the East River's tidal currents. Hydro Green Energy is another US based company that builds and operates kinetic hydro power projects that generate electricity from moving water river currents, tidal currents, and ocean currents without having to construct dams or other infrastructure. In addition to its abundant solar power and wind power resources, the United States Pacific Northwest is also uniquely located to capture the renewable energy of the ocean. Buoys, turbines, and other technologies can capture the power of waves and tides and convert it into clean, pollution-free electricity. Oregon and Washington have among the strongest wave energy resource in the United States and could eventually generate several thousand megawatts of electricity using wave resources. Commercial projects are currently under development in this area as well as California and Alaska.
In Europe, Scottish Power is proposing to build tidal power turbines in Scotland, under plans that will see it develop a manufacturing facility capable of serving three tidal farms and exporting turbines to other utilities carrying out similar projects. These turbines will be mounted on the sea bed and aligned to the tidal flow. Each of these turbines will generate around 1MW of output, and if 60 are installed as planned, they will generate enough energy to power 40,000 homes. They hope to have the project up and running by 2011.
Other sites include the White Sea in Russia and the Rance River in France which is the largest tidal power generating site in the world. Southeast Asia is another area ocean currents could be exploited for energy. In particular, the Chinese and Japanese coasts, and the large number of straits between the islands of the Philippines are suitable for development of tidal power generation from coastal currents. There are other tidal and wave energy projects either being planned or in production around the world.
Several models for tidal facilities have emerged in recent years, including tidal lagoons, tidal fences, and underwater tidal turbines, but none are commercially operating. Perhaps the most promising is the underwater tidal turbine. Several tidal power companies have developed tidal turbines, which are similar in many ways to wind turbines.
Advantages of Tidal Power:
There are many advantages to tidal power. Once the dam and the plant are set up, tidal power is free and it is a renewable energy resource. It produces no greenhouse gases or other wastes. Tidal power produces electricity reliably, since tides are totally predictable and tidal power facilities are inexpensive to maintain. Turbine design, which acts as a highly efficient underwater vertical-axis windmill, could produce energy for as cheaply as two cents per kilowatt hour, well below commercial grid energy wholesale prices today, according to a few studies. With more than half the planet being covered by water it is time to put some resources into this type of energy.
Another incentive for tidal power and wave power is government grants and loans. Many countries in Europe are providing support for clean energy projects like tidal energy. They want to meet ambitious targets for clean, green energy. The Unites States and Canada have also provided grants and loans to certain companies that wish to develop tidal energy.
Disadvantages of Tidal Power:
Tidal-power projects are very expensive, since massive structures must be built in difficult saltwater environments. The inherent corrosive nature of salt water leads to much higher maintenance costs There are relatively few coastal locations in the world where the tidal range (the difference between high and low tides) is large enough to justify exploitation of the available tidal energy. Not only must there exist a sufficiently high tidal range for construction of an economically practical plant, but the site should also include a natural bay which can store a large volume of seawater at high tide and be situated within the estuary that the operation of the plant will not significantly change the tidal resonant system. There are other issues in regard to tidal power. The tidal area can be hurt because the natural tide cycle is interrupted and the volume of moving water is reduced because the dam can't be built with a large enough opening to allow all water to enter. Potentially the largest disadvantage of tidal power is the effect a tidal station can have on plants and animals in the estuaries. Wave energy is dependant on the waves where sometimes you'll get loads of energy and sometimes almost nothing. Wave energy requires a suitable site where waves are consistently strong. Wave and tidal power is not always feasible. Research into the environmental impacts of tidal power is limited. Concerns about the impacts of tidal power technologies have caused recent endeavors to focus on tidal turbines and tidal fences. Tidal turbines can operate with tides and currents some distance from land, like underwater wind farms. History has shown that there are always consequences for an ecosystem when humans tamper with the natural balance of an environment.
Tidal Power cuts Greenhouse Gases and Global Warming:
Worldwide potential for wave and tidal power is enormous; however, local geography greatly influences the electricity generation potential of these technologies. Tidal power and wave power are part of the vast renewable energy sources that need to be used in order to offset global warming and greenhouse gas emissions. Ocean water is abundant and we are starting to realize the potential of using it for producing clean energy. Clearly there are still technical difficulties to overcome, but in the next few years, countries will begin to see wave power and tidal power connected to energy supplies. In addition to other alternative energy sources such as solar power and wind power using tidal energy can cut down our dependence on foreign oil and benefit our environment.
Short video taken of Reversing Falls, on the Bay of Fundy.
Pulp Mill on the edge of Reversing Falls, on the Bay of Fundy.
Pulp Mill and surrounding area
Reversing Falls, Bay of Fundy Pictures
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