Hydro -electricity,Waves & Tides

Question 1

How does Hydro-electricity work
What is environmental impact
Advantages /Disadvantages

Answer 1

• flooding of valley by building a dam. Water allowed out through turbines
• Big impact = 1. on environment (rotting vegetation releases methane and Co2), 2. loss of habitat, 3. reservoirs look unsightly when dry up
• Advantage = 1. Immediate response to increased demand for electricity 2. Reliable (unless drought) 3. No fuel costs 4. Minimal running costs 5. Good to generate electricity on small scale in remote areas

Water stored at a hydroelectric dam has potential energy. When it runs through the dam this turns to kinetic energy. The kinetic energy of the moving water is used to generate electricity.

• Disadvantage = initial costs high

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The advantages and disadvantages of hydroelectricity
Advantages
Hydroelectric energy is renewable. Find out what renewable energy is here: What is renewable and non-renewable energy?

It is a reliable energy source. Unlike wind and the sun, we know that stored water can provide a 24/7 source of kinetic energy.

Once built, it does not produce harmful emissions. This means it does not contribute to the production of greenhouse gases and climate change.

Disadvantages
To create a hydroelectric dam, you need to flood an area of land, which damages local environment and animal habitats.

In some cases, people may be forced to move home if they live on land that is to be flooded or developed due to the construction of a hydroelectric power plant.

Building hydroelectric dams is expensive and uses lots of concrete, which releases greenhouse gases when it is made.

Question 2

How does wave power work

Advantages/Disadvantages

Answer 2

Lots of small wave powered turbines placed around coast. Connected to generator

Key points
Waves contain kinetic energy. By using turbines, the kinetic energy of waves can be transferred into electrical energy.
Wave power does not use up any fuels and so it is a great source of clean, renewable energy source.
Although the technology is still in development, Scotland has over six thousand miles of coastline, and the potential to generate lots of electricity

Waves are created when the wind blows air across the surface of water. The stronger the wind, the bigger the waves.
And the bigger the waves the more kinetic energy they have.
Kinetic energy can be transferred into electrical energy by using turbines that rely on the movement of waves. The turbines transfer this kinetic energy to generators. When the generators spin, they transfer the kinetic energy to electrical energy.
There are lots of different types of device to turn wave energy into electricity. Three of the main types are called attenuators, absorbers and oscillator. Even though they look different, they all work using the same energy transfers.

Advantages = 1. No fuel costs 2. No pollution 3. Minimal running costs 4. Useful on small islands

Disadvantages = 1. Disturbs seabed 2. Disrupts habitats 3. Spoils views 4. Hazard to boats 5. Fairly unreliable 6. Initial costs high 7 can’t be large scale

Advantages and disadvantages of wave power
Advantages
Wave power is renewable since no fuel is needed. All that’s needed is wind and water.
Wind and water are free, natural, and we have an infinite supply.
It is clean as there is no pollution generated.
Once set up, the costs are low.
Disadvantages
Initial building costs are high and the process is difficult as turbines need to be built in high winds around giant waves.
Building wave turbines can also have a damaging impact on local marine ecosystems.
Turbines can obstruct shipping lanes.
Some people think turbines destroy natural beauty of the coastline.
It is not a reliable source of energy since on a calm day there will be no wind

Question 3

What is a Tidal Barrage and how does it work

Advantages/Disadvantages

Answer 3

Big dam across river estuaries with turbines. As tide comes in, it fills estuary. Water is then allowed out through turbines at controlled speed - tides produced by gravitational pull of sun and moon

Advantages = 1. No pollution 2. Tides are reliable 3. No fuel costs 4. Minimal running costs 5. Tidal power has potential to produce significant energy in some estuaries
Disadvantages 1. Initial costs are moderately high 2. Lower tides don’t create as much energy