Tidal Energy

ADVANTAGES

DISADVANTAGES

Tidal energy doesn't produce greenhouse gases.
As 71% of Earth’s surface is covered by water, there is scope to generate this energy on large scale.
We can predict the rise and fall of tides as they follow cyclic fashion.
Efficiency of tidal power is far greater as compared to coal, solar or wind energy. Its efficiency is around 80%.- Large in size- Severn barrage would produce the same amount of energy as 5 nuclear power stations
Maintenance costs are relatively low.
Tidal Energy doesn’t require any kind of fuel to run.
The energy density of tidal energy is relatively higher than other renewable energy sources.
Benefits the estuary as erosion rates reduced behind the barrage

Cost of construction of tidal power plant is high.
Intensity of sea waves is unpredictable and there can be damage to power generation units.
Influences aquatic life adversely and can disrupt migration of fish- adverrse effect on spawning fish and salmon
The actual generation is for a short period of time. The tides only happen twice a day so electricity can be produced only for that time.
Frozen sea, low or weak tides, straight shorelines, low tidal rise or fall are some of the obstructions.
Technology is still not cost effective and more technological advancements are required to make it commercially viable.
Usually the places where tidal energy is produced are far away from the places where it is consumed. This transmission is expensive and difficult.
Flooding of wetlands bordering estraries, often homes of species of migrating birds, is damaging

CASE STUDY: La Rance Tidal Barrage, N France

1967

Largest tidal power barrage in the world.

produces enough electricity for over 19,000 homes.

Rance River estuary chosen due to its large tidal range; average tidal range of 8m.

Rance Barrage is 750m long and 13m high.

Since constructed, has produced approx £3.30bn worth of electricity.

Since construction needed to drain estuary in the initial years after construction was completed, there were severe impacts to local environment; however 10 years later it was considered that Rance estuary once again had a rich diversity of aquatic life.

INFORMATION

Greatest tidal range- best potential & sites suggested for UK, including the Severn.

Schemes with reversible blades could harness power of in & out going tides.

Major drawback= economic & environmental cost. Tidal barrage across estuary of River Rance close to St Malo, Brittany, France & another large-scale scheme, which began generating electricity in 1984, in Nova Scotia, Canada in Bay of Fundy.