History
Utilizing the tides was first done in the 18th century to compete with windmills and another water technology–water wheels. Water mills were quite popular but became scarce once the steam engine gained its popularity. Tidal power plants have not traditionally been a popular way to convert energy into electricity.

Current Usage
Presently France is the only country that successfully uses the tides as a power source. In their country, tidal power accounts for just about 240 megawatts of power at the world’s largest tidal plant–the La Rance. This facility was constructed in 1966, and is currently Europe’s only tidal plant. This plant provides roughly enough energy to fuel 240,000 homes. Though the energy source is both reliable and plentiful, extracting usable power from it is not.

Future
The comparison between tidal energy now and wind energy 10 years ago has been made. Researchers are hopeful that developments to the technology can be made. One offshoot of tidal power that is currently being researched is the possibility of using the energy extracted from waves to produce hydrogen for fuel or fuel cells. There is hope that this would be used specifically in remote areas such as the Highlands and Islands of Scotland.

World wide only about 20 sites have been identified as having the potential to harness the power from the waves. This is due to the fact that between 12 and 18 feet difference (called ’head‘) between high and low tide is needed, and very few areas experience this range of heights. (In the United States one of the only usable sites is at Nantucket, though it is unlikely that they will begin construction due to the unpleasing appearance of the plants)

Another option yet to be completely explored would be to use offshore turbines.

(Somewhat comparable to an underwater wind farm.) These would be quite a lot cheaper than building the large-scale bridges and wouldn’t pose such risks to the environment. There are many more potential sites for this type of technology than the current tidal technologies. Some would speculate that these would pose risk to marine life, but it has been pointed out that they pose far less risk than the propellers on ships, as they are both stationary and rotate 10 times more slowly.

Advantages and Disadvantages:

• Once constructed, it is a free source.
• No greenhouse or other gas emissions.
• Reliable.
• Inexpensive to maintain.
• Tides are very predictable.
• Needs to be close to the coast.
• Not a continual energy supply throughout the day.
• Not aesthetically pleasing.

Tidal power has the potential to one-day account for one fiftieth of our total power consumption, so they could never solve our current energy dilemma. They could provide assistance, but never more than that–we could not totally rely on this technology. The greatest drawback is that we know little about the effect this has on marine life. There is always a potential threat to the natural ecosystems when we disrupt nature’s processes, and the ocean is no exception. The reduced tidal flow that Tidal energy systems cause has environmental impacts on tidal basins because they decrease the flow of the tides and also silt buildup. There is speculation that if we use this technology to a great degree the tides will slow down, posing a great treats to the ecosystem.

Wave energy is produced when electricity generators are placed on the surface of the ocean. The energy provided is most often used in desalination plants, power plants and water pumps. Energy output is determined by wave height, wave speed, wavelength, and water density. To date there are only a handful of experimental wave generator plants in operation around the world.

The Aguadora Wave Park (AWP) in Portugal is the worlds first commercial wave farm. The AWP produces roughly 2.25 Mega-Watts of power (enough for 1500 homes) and cost just over 8.5 million euros to deploy (though by 2009 costs are expected to exceed 70 million euros).

Construction and Maintenance

Most turbines require a constant, powerful flow which works in opposition to the very nature of waves, as waves are inconsistent in both direction and power. Powerful storms and the corrosive power of salt water are also adversarial to the construction of a reliable energy collection device. Accounting for the aforementioned problems, a device and its maintenance may become too expensive to be a reliable alternative to coal, oil, biodiesel or even solar power.

Harnessing the Waves

Wave energy collection is, however, remarkably passive. Unlike oil which requires a distillation process before energy can be used, wave energy is automatically converted by turbines. Wave energy is also environmentally friendly, as it creates no atmospheric pollution and has a small carbon footprint (non-existent if not for the manufacture of its devices). More-so, it allows us to utilize a space which has, for most of history, been underutilized: the ocean.

The flowing waters in the rivers and tidal waves can be a good source of alternative energy. With 70% of the earth’s surface covered with water, a great 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.

The Future of Wave Power

According to Trey Taylor Co founder & president of Verdant Power, 4 commercial projects are planned for the next 3-5 years which should have the capacity to produce more than 200 MW when operating in waterways. As great minds continue to tackle the problems of renewable energy, we may see major advancements making wave energy more feasible. Groups such as OREC (Ocean Renewable Energy Coalition), continue to drum up support for projects, but it seems policy makers are a bit uncertain of wave energy’s true benefits.

For now we should focus on implementing wind power and solar power strategies to replace our dependence on oil. It may seem like a panacea on paper, but the reality exposes the truth, wave power is just not ready for wide-scale commercial use yet.