Renewable resources

Explain how wind power produces energy

Wind power produces energy through the use of wind turbines. Each wind turbine has a generator inside of it, and the rotating blades turn the generator and produce electricity.

What are the advantages of using wind power?

• No fuel costs.

• No pollution except a small amount when being manufactured.

What are the disadvantages of using wind power?

• They have a high set up price.

• They cause visual pollution and if placed near homes, can be noisy.

• They're not always reliable due to being dependent on weather, meaning they cannot always meet demand.

• Output varies due to changes in wind power.

Overall, how reliable is using wind power?

Fairly reliable, but not as reliable as using the non-renewable resources.

Explain how solar cells produce energy

Solar cells generate electricity by converting light energy from the sun directly into electrical energy through the photoelectric effect. When sunlight strikes a solar cell, light particles (photons) excite electrons in the semiconductor material, causing them to break free and flow through the cell as an electrical current.

What are the advantages of using solar cells?

• Almost no cost to run.

• No pollution when being used.

• Can be used in various countries.

What are the disadvantages of using solar cells?

• Costs to make are high.

• Uses a lot of energy to make.

• It's not constant because sunlight hours vary, meaning it doesn't always meet demand.

• Most suited to sunny countries.

Overall, how reliable are solar cells?

Solar cells are not very reliable at all.

What does 'biofuels' include?

There are 3 main forms of biofuels:

• Wood

• Waste

• Crops

How do we use wood as a biofuel?

Wood can be burned as a biofuel in many forms - firewood, charcoal, wood chips and sawdust. It is very readily available and can be easily grown.

How do we use waste as a biofuel?

Waste products from plants and animals will rot due to the action of bacteria. This produces biogas (methane) which can be burnt to generate electricity, heat water or fuel vehicles.

How do we use crops as a biofuel? What are the advantages and disadvantages?

Crops are often grown specifically to be used as a biofuel. These are good as they have a low pollution rate, however it does take away space for food growing which could cause a food shortage.

What about the carbon footprint of biofuels?

They all produce CO2, however the plants you grow (either to burn or to feed the animals) also remove CO2 so the carbon footprint appears to be 0. But, there is debate around this because for this to work you would need to be growing crops at the same rate you are burning them, if not quicker. It also doesn't take into account the CO2 produced from growing, harvesting and processing the crops. Despite these issues, biofuels typically have a lower carbon footprint than fossil fuels.

What are some overall disadvantages of biofuels?

• Land clearing can cause species to lose their habitats.

• Using up land also means less space for food growth.

• Crops take time to grow which may make it hard to meet demands.

• Produces CO2, methane, soot and smoke.

• Cost is very high.

Overall, how efficient are biofuels?

They are moderately efficient but still not as efficient as fossil fuels.

How can we use water to produce energy?

There are 3 main ways we use water to produce energy:

• Hydroelectric power

• Wave power

• Tidal barrages

Explain how hydroelectric power produces energy

Hydroelectric power usually requires the flooding of a valley by building a big dam. Water is then allowed out through the turbines.

What are the advantages of using hydroelectric power?

• There is no pollution.

• Can provide an immediate response to increased demand.

• Very efficient and reliable

• No fuel costs and minimal running costs.

• Little to no impact on humans.

What are the disadvantages of using hydroelectric power?

• Can massively impact the environment around the valley = flooding leads to rotting vegetation which releases methane and CO2 and also causes habitat loss for some animals and humans.

• Initial cost to build is high

• Can fail during drought.

• Only really good for small scale energy in remote areas.

Explain how wave power produces energy

Lots of small wave powered turbines are placed around the coast. Like with the wind power the moving turbines are connecter to a generator.

What are the advantages of using wave power to produce energy?

• No pollution.

• Very efficient when waves are good and can generate lots of electricity.

• No fuel costs and minimal running costs.

• Can provide large scale energy.

What are the disadvantages of using wave power to produce energy?

• Disturbs the seabed and habitats of marine animals.

• Spoils the view of the coast.

• Can be a hazard to boats.

• Initial costs to build is high

• Fairly unreliable because they need wind to work

Explain how tidal barrages produce energy

Tidal barrages are big dams built across river estuaries with turbines in them. As the tide comes in and out, the water is allowed in and out through the turbines at a controlled speed.

What are the advantages of tidal barrages?

• No pollution.

• No fuel costs and minimal running costs.

• Potential for significant amount of energy at a very high efficiency.

• Pretty reliable as it happens twice a day.

What are the disadvantages of tidal barrages?

• Prevent free access by boats.

• Spoil the view

• Alter habitat of wildlife.

• The height of the tide can affect the amount of energy produced.

• Can only be used in some of the most suitable estuaries.