Sherman.wiki.spring,2011

By Crystal Sherman
 * Tidal Wave Energy **



The moon is caught in the gravitational pull of the earth. Tides occur because the moon also exerts its gravitational field on the earth. While it is not strong enough to move land, it is strong enough to impact large bodies of water, primarily oceans. But what actually causes the tide? Well, the moon does not rotate the earth at the same rate as the earth spins. This means that whatever side of the earth happens to be facing the moon at a particular time seems to have the biggest impact of the moons gravity. This causes water to be pulled in this direction, causing tides. The end result is we have two high and two low tides every day.
 * What is a tide? **

**What is tidal energy?** The movement of a mass of water like an ocean requires a ton of energy. This energy is originally gravitational, but is formed as the kinetic energy of water moving. Tidal energy works by trying to capture this kinetic energy.

**What is the problem at hand?** The problem at hand is that our nonrenewable resources are depleting at an extremely rapid pace. Without them we will need to find new energy sources to supply enough energy to satisfy the needs of the people that populate this earth. Another problem is that fossil fuels create pollution, especially air pollution.



The driving force of the problem is the humans that inhabit this earth, we are the problem. We are over using our resources and soon they will not be there for us to use. We waste energy all the time.
 * What is the driving force of the problem? **



 People are currently trying to fix this problem. We are inventing new was to harvest energy. There are many, many solutions that people have come up with so far. Also the new ways that people are developing don’t hurt the environment. In a way we are tackling two major problems that go hand in hand, at once. We are looking for new energy sources while preserving what is left of our environment. The solution that I want to focus on is tidal energy as a source of energy that we can use to convert to electricity. There are many techniques that have been used to gather this tidal energy such as offshore turbines, Powerbuoys, tidal barrages, and tidal energy generators. Some other techniques include the Oyster, Ocean Energy Bionics, and many more.
 * How is the crisis being fixed? **

 Offshore Turbines

 PowerBuoy

 Tidal Energy Generators

 Tidal Barrages


 * <span style="color: black; font-family: Arial,sans-serif; font-size: 12pt;">The Advantages **

<span style="font-family: Arial,sans-serif; font-size: 16px; line-height: 24px;">There are many advantages to tidal wave energy. <span style="color: black; font-family: Arial,sans-serif; font-size: 12pt;">One is that the tides are a predictable renewable resource. The energy is constant. Tidal energy has an efficiency of 80% in converting the potential energy of the water into electricity. <span style="font-family: Arial,sans-serif; font-size: 16px; line-height: 24px;">The energy that is produced is clean and non-polluting. There is no carbon dioxide or any other by-products released. <span style="color: black; font-family: Arial,sans-serif; font-size: 12pt;">Tidal power can provide other benefits such as bridges and roads, which are built over the tidal generators <span style="color: black; font-family: Georgia,serif; font-size: 10pt;">. <span style="font-family: Arial,sans-serif; font-size: 16px; line-height: 24px;">It produces no greenhouse gases or other waste. The energy is free once you built the generators, turbines, etc. Maximum ocean energy can reach 100,000 watts per square meter, compared to 1000 watts per square meter for solar energy. They are not expensive to maintain and some of the techniques used to gather the energy have very little environmental impact. Once a plant is built it is expected to be around for between 75 and 100 years, that is a lot of energy being produced!


 * <span style="color: black; font-family: Arial,sans-serif; font-size: 12pt;">The Disadvantages **

<span style="color: black; font-family: Arial,sans-serif; font-size: 12pt;">On the other hand there are some disadvantages to using this form of energy as well. Holding back the tide allows silt to build up on the river bed. The dams and barrages sometimes interfere with shipping. Pose same threats as large dams, altering the flow of saltwater in and out of estuaries, which changes the hydrology and salinity and possibly negatively affects the marine mammals that use the estuaries as their habitat. Turbidity decreases as a result of smaller volume of water being exchanged between the basin and the sea. The average salinity inside the basin decreases, also affecting the ecosystem. A barrage across an estuary is very expensive to build, and affects a very wide area - the environment is changed for many miles upstream and downstream. Many birds rely on the tide uncovering the mud flats so that they can feed. There are few suitable sites for tidal barrages. Only provides power for around 10 hours each day, when the tide is actually moving in or out. Tidal energy is currently more expensive to generate than conventional energy or that from many other renewable sources. Operation and control must be provided remotely and maintenance is complicated due to sea-basing of the generation facilities. The generating facilities and mooring infrastructure are potential navigational hazards. The barrages are expensive to construct. It may look like a lot of disadavntages but most of them only relate to barrages, which is only one way techniques used in harvesting this energy.

<span style="font-family: Arial,sans-serif; font-size: 16px; line-height: 24px;">Less than 1% of the world's energy supply is produced by tidal wave energy. This is due to the fact that it is so new and no large scale projects have been started yet. Also since there are so many techniques out there there is a lot of experimenting with which technique will be the most effective and cost efficient. It has the potential to be a good renewable energy source but since it is just starting to be used, it has a long way to go before it is perfected. Countries that are on the coast line use this kind of energy because the ocean is need for this type of energy to be produced. For this to be create a lot of energy it would need to be done on a large scale. A lot of time and money would have to be put into this. The cost however, would be a one time only cost, except for the cost of maintenance. The turbines or other devices used to gather the tidal wave energy would need to be mass produced and many of them would need to be placed into the ocean to harvest all of that energy. At such a large scale the energy would be supplied to the world would be a much larger amount than the amount of energy that is being supplied as of right now.



<span style="font-family: Arial,sans-serif; font-size: 12pt;">Rance Tidal Power Station was the first tidal power station built in Brittany, France. The construction took over 6 years, from 1960-1966. This proves that advantages in renewable energy were already being made is the early 1960’s. It is the largest tidal power station in the world and is generated by 24 turbines. This turbines are special reversible turbines. Not only is it producing energy (with an annual output of 600 GWh), but it is also generates money be being a tourist <span style="font-family: Arial,sans-serif; font-size: 16px; line-height: 24px;">attraction.

<span style="color: black; font-family: Arial,sans-serif; font-size: 11pt;">In other areas of the world they are working on developing tidal power stations as well. The Snohomish County Public Utility District, just north of Seattle, WA, received a $10 million grant from the Energy Department for the tidal project now in the final phase of obtaining permits. The turbines would generate an average of 100 kilowatts of electricity, enough to power 50-100 Washington homes during the pilot phase. <span style="color: black; font-family: Arial,sans-serif; font-size: 11pt;">"We want to monitor the effects of this particular project, but also understand the processes so we can apply the findings to other potential tidal energy sites," says Brian Polagye, UW research assistant professor of mechanical engineering.


 * <span style="color: black; font-family: Arial,sans-serif; font-size: 12pt;">How Would you Improve Tidal Wave Energy? **

<span style="font-family: Arial,sans-serif; font-size: 12pt;">After learning about tidal wave energy the first thing that I would do to change it would be to perfect a couple methods, to narrow down the wide range of devices that are being used today. If only a couple devices were being produced then more people could focus their energy and time into improving those devices. Next I would try to improve the efficiency of the devices and locate them in areas where they will obtain the most energy. It would be a trial and error experiment and over time the results would help improve these devices. Once all of this has happened, I would work on expanding where the devices are used. Then start using them in large scale projects to obtain even more energy. All of these improvements would be used to help this form of renewable energy become a useful source of energy that can be easily obtained and inexpensive.

**<span style="font-family: Arial,sans-serif; font-size: 12pt;">Sources ** <span style="font-family: Arial,sans-serif; font-size: 12pt;">Environmental News Network- [] <span style="font-family: Arial,sans-serif; font-size: 12pt;">Wikipedia - [] <span style="font-family: Arial,sans-serif; font-size: 12pt;">Solar Feeds, News and Comemtary - [] <span style="font-family: Arial,sans-serif; font-size: 12pt;">AE Tidal Power- [] <span style="font-family: Arial,sans-serif; font-size: 12pt;">Renewable Energy Development- [] <span style="font-family: Arial,sans-serif; font-size: 12pt;">Energy Sources: Tidal Power- [] <span style="font-family: Arial,sans-serif; font-size: 12pt;">Ocean Energy Council- []  <span style="font-family: Arial,sans-serif; font-size: 12pt;">The Environmental Blog.org- [] Energy Resources: Hydroelectric Power-[]