Tidal Power Schemes
The phrase 'tidal power scheme' is used to refer to a particular method of capturing energy from the tides. For instance, a tidal barrage is one type of scheme while a tidal stream generator is another. There are four main types of tidal power scheme.
|
Scheme |
Description |
|
Tidal Barrage |
A barrage is a dam and these systems work by trapping water a high tide (usually) and then releasing it through defined channels that carry it through a turbine. |
|
Tidal Lagoon |
This is similar to a tidal barrage, except the damn is replaced by a 360 degree enclosure that creates a pool. |
|
Tidal Stream Generator |
These work much like wind turbines, but they use water rather than wind. As the tide flows in and out, it pushes the rotors of a turbine. |
|
Dynamic Tidal Power |
This strategy uses long walls the jut out perpendicular to the shore. As the tide passes the wall, it is trapped on one side or the other, creating head. This high water is only allowed to flow past the wall by flowing through define paths that carry it past generators. |
Each tidal power scheme has advantages and dsadvantages and each is suited to specific locations. The following table explains the advantages and disadvantages of each scheme. One of the disadvantages of all tidal power systems is that they cannot generate power 24 hours per day. Because tides ebb and flow, power generation drops when the tide is switching from ebb to flow. Even the best tidal systems only generate power for 20 hour/day at most. Storage systems or alternative generation methods are needed for the hours when electricity is not being generated by these systems.
|
Scheme |
Advantage |
Disadvantage |
|
Tidal Barrage |
High power generation Proven design Long life span Low maintenance Can provide flood control |
Requires high tidal flows Most environmental impact Expensive to build |
|
Tidal Lagoon |
High power generation Proven design Less ecological impact than barrage Low maintenance |
Requires high tidal flows Expensive Generates less power than barrage No assistance in flood control |
|
Tidal Stream Generator |
Moderate power generation Modular Low cost Least environmental impact |
Difficult maintenance Corrosion more problematic Requires flow of 2.0 m/s or greater |
|
Dynamic Tidal Power |
Huge power generation capability Single installation |
Unproven, untested design Extremely expensive Massive engineering feat Limited available sites |
