Pros
<span><span>Renewable.
Requires no fuel.
</span>Emission-free
Reliable, a plant can last 100 years
High efficiency
Predictable output
Could potentially provide a storm surge barrier.
Environmental impacts are local, not global</span>
Cons
<span>Expensive to build
<span>Very location specific (only 20 sites identified with high potential)
</span>Non-continuous, storage or grid-backup required
Locations are often remote
Barrages may restrict access to open water
Can change tidal level of surrounding area
Impact on fish, marine mammals and birds
Disrupts regular tidal cycles
<span>Decreases salinity in tidal basins
</span>Mud flats (where many birds feed) adversely impacted
Captures dirt, waste and pollution near the coast
<span>Reduces kinetic energy in the ocean</span></span>