The worldwide potential for tidal power is estimated to be 700 TWh a year. Currently, tidal power is early in the development stages and not able to compete with fossil fuels. However, Focus on renewable energy sources and demand for clean energy contributes to a rapid development of methods to harness this energy source. What are the pros and cons of tidal energy and what can we expect in the future?
Advantages of Tidal Energy
Tidal Energy is a renewable energy source. This energy source is a result of the gravitational fields from both the sun and the moon, combined with the earth’s rotation around its axis, resulting in high and low tides.
It is this difference in potential energy that is the source of power generation from tidal energy, whether we are talking about stream generators, tidal barrages or more the more recent technology, dynamic tidal power (DTP).
So, why is tidal energy renewable? Compared to fossil fuels or nuclear reserves, the gravitational fields from the sun and the moon, as well as the earth’s rotation around its axis won’t cease to exist any time soon.
Tidal power is an environmentally friendly energy source. In addition to being a renewable energy, it does not emit any climate gases and does not take up a lot of space.
However, there are currently very few examples from real tidal power plants and their effects on the enviroment. An important task is therefore to study and assess these things.
Tidal currents are highly predictable. High and low tide develop with well-known cycles, making it easier to construct the system with right dimensions, since we already know what kind of powers the equipment will be exposed to.
Because of this, even though the turbines that are being used (tidal stream generators that is) are very similar to wind turbines, both the physical size and the installed capacity has entirely other limitations.
4. Effective at Low Speeds
Water has 1000 times higher density than air, which makes it possible to generate electricity at low speeds. Calculations show that power can be generated even at 1m/s (equivalent to a little over 3ft/s).
5. Long Lifespans
We have no reason to believe that tidal power plants are not long lived. This ultimately reduces the cost these power plants can sell their electricity, making tidal energy more cost-competitive. The tidal barrage power plant La Rance was opened already in 1966 and still generates large amounts of electricity.
Disadvantages of Tidal Energy
1. Environmental Effects
As previously mentioned, the effects tidal power plants have on the environment are not completely determined yet. We know that these power plants generate green electricity
Tidal barrages relies on manipulation on ocean levels and therefore potentially have the environmental effects on the environment similar to those of hydroelectric dams. Technological solutions that will resolve some of these issues are currently being developed.
2. Close to Land
Tidal power plants needs to be constructed close to land. This is also an area where technological solutions are being worked on. Hopefully in a few years we can exploit weaker tidal currents, at locations further out in the sea.
It is important to realize that the methods for generating electricity from tidal energy is a relatively are relatively new technologies. It is projected that tidal power will be commercially profitable within 2020 with better technology and larger scales.
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Author: Mathias Aarre Mæhlum
Last Update: 16 October 2012