| Tidal power is using the tides to extract energy | | | | There is hope that this would be used specifically |
| to convert into electricity. The tides are the result | | | | in remote areas such as the Highlands and Islands |
| of the gravitational force between the Earth and | | | | of Scotland. |
| Moon. On a daily basis this force pulls up tons of | | | | World wide only about 20 sites have been |
| water, thus the tides. The tides are also brought | | | | identified as having the potential to harness the |
| back down, allowing for tidal power to be used | | | | power from the waves. This is due to the fact |
| twice daily, which would sum to about 10 hours. | | | | that between 12 and 18 feet difference (called |
| Tidal power is catching this water when it is at | | | | 'head') between high and low tide is needed, and |
| high tide and storing it in reservoir type structures | | | | very few areas experience this range of heights. |
| until the time of low tide. During low tide, the | | | | (In the United States one of the only usable sites |
| water is released, allowing it to flow back out to | | | | is at Nantucket, though it is unlikely that they will |
| sea through the turbines, and thus generating | | | | begin construction due to the unpleasing |
| power. In order to create a tidal plant, we build a | | | | appearance of the plants) |
| dam, called a barrage, at the bottom of a tidal | | | | Another option yet to be completely explored |
| basin. This includes a device called a sluice, which | | | | would be to use offshore turbines |
| opens up allowing the tide to come in at high tide. | | | | (Somewhat comparable to an underwater wind |
| This water rushes past a turbine that is attached | | | | farm.) These would be quite a lot cheaper than |
| to a generator, or in some cases the water | | | | building the large-scale bridges and wouldn't pose |
| pushes air through tunnels that then act like wind | | | | such risks to the environment. There are many |
| through a turbine. When it is time for the tide to | | | | more potential sites for this type of technology |
| go out at low tide, the function of the sluice | | | | than the current tidal technologies. Some would |
| reverses and the water flows back out through | | | | speculate that these would pose risk to marine |
| the turbines. | | | | life, but it has been pointed out that they pose far |
| History | | | | less risk than the propellers on ships, as they are |
| Utilizing the tides was first done in the 18th | | | | both stationary and rotate 10 times more slowly. |
| century to compete with windmills and another | | | | Advantages and Disadvantages: |
| water technology--water wheels. Water mills were | | | | Once constructed, it is a free source. |
| quite popular but became scarce once the steam | | | | No greenhouse or other gas emissions. |
| engine gained its popularity. Tidal power plants | | | | Reliable. |
| have not traditionally been a popular way to | | | | Inexpensive to maintain. |
| convert energy into electricity. | | | | Tides are very predictable. |
| Current Usage | | | | Needs to be close to the coast. |
| Presently France is the only country that | | | | Not a continual energy supply throughout the day. |
| successfully uses the tides as a power source. In | | | | Not aesthetically pleasing. |
| their country, tidal power accounts for just about | | | | Tidal power has the potential to one-day account |
| 240 megawatts of power at the world's largest | | | | for one fiftieth of our total power consumption, |
| tidal plant--the La Rance. This facility was | | | | so they could never solve our current energy |
| constructed in 1966, and is currently Europe's only | | | | dilemma. They could provide assistance, but never |
| tidal plant. This plant provides roughly enough | | | | more than that--we could not totally rely on this |
| energy to fuel 240,000 homes. Though the | | | | technology. The greatest drawback is that we |
| energy source is both reliable and plentiful, | | | | know little about the effect this has on marine life. |
| extracting usable power from it is not. | | | | There is always a potential threat to the natural |
| Future | | | | ecosystems when we disrupt nature's processes, |
| The comparison between tidal energy now and | | | | and the ocean is no exception. The reduced tidal |
| wind energy 10 years ago has been made. | | | | flow that Tidal energy systems cause has |
| Researchers are hopeful that developments to | | | | environmental impacts on tidal basins because |
| the technology can be made. One offshoot of | | | | they decrease the flow of the tides and also silt |
| tidal power that is currently being researched is | | | | buildup. There is speculation that if we use this |
| the possibility of using the energy extracted from | | | | technology to a great degree the tides will slow |
| waves to produce hydrogen for fuel or fuel cells. | | | | down, posing a great treats to the ecosystem. |