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## Answers

[edit] Example calculation of tidal power generation

Assumptions:

Let us assume that the tidal range of tide at a particular place is 32 feet = 10 m (approx)

The surface of the tidal energy harnessing plant is 9 km² (3 km × 3 km)= 3000 m × 3000 m = 9 × 106 m2

Density of sea water = 1025.18 kg/m3

Mass of the sea water = volume of sea water × density of sea water

= (area × tidal range) of water × mass density

= (9 × 106 m2 × 10 m) × 1025.18 kg/m3

= 92 × 109 kg (approx)

Potential energy content of the water in the basin at high tide = ½ × area × density × gravitational acceleration × tidal range squared

= ½ × 9 × 106 m2 × 1025 kg/m3 × 9.81 m/s2 × (10 m)2

=4.5 × 1012 J (approx)

Now we have 2 high tides and 2 low tides every day. At low tide the potential energy is zero.

Therefore the total energy potential per day = Energy for a single high tide × 2

= 4.5 × 1012 J × 2

= 9 × 1012 J

Therefore, the mean power generation potential = Energy generation potential / time in 1 day

= 9 × 1012 J / 86400 s

= 104 MW

Assuming the power conversion efficiency to be 30%: The daily-average power generated = 104 MW * 30% / 100%

= 31 MW (approx)

A barrage is best placed in a location with very high-amplitude tides. Suitable locations are found in Russia, USA, Canada, Australia, Korea, the UK. Amplitudes of up to 17 m (56 ft) occur for example in the Bay of Fundy, where tidal resonance amplifies the tidal range.