Tidal Barrages

• Tidal barrages use the Sun and Moon's gravity
• Tides are used in lots of ways to generate electricity. The most common method is building a tidal barrage
• Tidal barrages are big dams built across river estuaries, with turbines in them. As the tide comes in it fills up the estuary. The water is then allowed out through turbines at a comtrolled speed
• Tides are produced by the gravitational pull of the Sun and Moon
• Tidal barrages cause no pollution
• The main problems are preventing free access by boats, spoiling the view and altering the habitat of the wildlife e.g. wading birds, sea creatures and organisms that live in the sand
• Tides are pretty reliable in the sense that they happen twice a day without fail, and always near to the prediced height
• The only drawback is that the height of the tide is variable so lower (neap) tides will provide significantly less energy than the bigger 'spring' tides
• Tidal barrages also don't work when the waterlevel is the smae either side of the barrage - this happens 4 times a day because of the tides
• Initial costs are moderately high, but there are no fuel costs and minimal running costs
• Even though it can only be used in some of the most suitable estuaries, tidal power has the potential for generating a significant amount of energy