7.1 Energy Choices & Security

What are the fossil fuels?

• Coal

• Natural gas

• Crude oil

What are fossil fuels made up of?

Formed from remains of plants and animals

• Chemical energy stored in fossil fuels from sunlight

• Energy from sun transferred to chemical energy stores vis photosynthesis

• Animals ate plants and energy transferred to their chemical store

What are the advantages of fossil fuels?

• Readily available on daily basis

• Reliable for large scale energy production

• Efficient - high energy

What are the disadvantages of fossil fuels?

• Non-renewable

• Prices increase as demand increases but supply is decreasing

• Produced harmful gases: CO2, sulfur dioxide - greenhouse effect, acid rain respectively

• Oil spills can occur during transport, damage environment

• Prices fluctuate rapidly

• Supplies can be affected by conflict and political disagreements

What are uses of fossil fuels?

• Transport

• Generating electricity

• Heating

What are majority of vehicles in world powered by?

Petrol, diesel, kerosene

What is an advantage and disadvantage of electric vehicles?

Advantage: produces zero carbon emissions

Disadvantage: when vehicle is charged, connected to national grid, which uses non-renewable and renewable energy sources

Why is the energy demand increasing?

• Higher demand for food leads to more intensive farming, requiring more energy for machines, light, heat

• Increasing industry requires energy for heating, lighting, machinery

• More transport needs more energy

• Urbanisation increases with development = more domestic appliances

• Increased wealth = buying more appliances, requiring energy

What are the renewable energy sources?

• Solar

• Biomass

• Hydropower

• Wind

• Wave and tidal

• Geothermal

How do solar cells work?

• Energy from sun falls on earth is transferred by radiation

• Visible light and IR converted to electricity

What are solar PV cells?

• Transfer energy from sunlight to produce current and generate electricity

• Energy can be stored in batteries for later use

What are solar PV cells made out of?

Semiconducting materials

What are the advantages of solar PV cells?

• Renewable

• Reliable in sunny countries

• No greenhouse gases/pollution

• Useful in remote places

• Small/large scale

What are disadvantages of solar PV cells?

• Need to be large scale to produce large amounts of electricity, expensive to set up

• Uses large areas of land

• Visual pollution

  • Unreliable (not enough sunshine)

Describe solar thermal panels

Transfer energy from sunlight to the thermal store of the solar panels which is used to heat water in pipes

What are advantages of solar thermal panels?

• Renewable

• Reliable

• No greenhouse gases/pollution

  • Can cut cost of energy bills for households

What are the disadvantages of solar thermal panels?

• Additional energy is still needed to heat water to a higher temperature in domestic households

  • Not reliable as sun doesn’t shine regularly

What are biofuels?

Renewable fuels from organic materials (plants/animal waste)

What is a difference between biofuels and fossil fuels in terms of energy density?

Biofuels are less energy dense

What are the advantages of biofuels?

• Renewable

• Some vehicles can be powered with this

• Carbon-neutral

  • No sulfur dioxide produced

What are the disadvantages of biofuels?

• Crops must be grown that take a long time

• Growing crops takes lots of land and takes resources needed for food productions

• Buring biofuels releases CO2 into atmosphere

What is hydropower?

When water stored above ground level has GPE and energy can be transferred to KE

Flowing water turns turbine to generate electricity

What are the advantages of hydropower?

• Can respond to demand quickly so is reliable and available

• Can generate large scale amounts of electricity in a short period of time

• Often in sparsely populated areas

What are the disadvantages of hydropower?

• Expensive to build and maintain

• Creating reservoirs sometimes results in need to flood valleys, which destroys habitats, towns, villages

• Pumping systems release large amounts of greenhouse gases

• Dam traps sediment which can affect ecosystems downstream

• Visual pollution

  • Prevents fish movement and migration upstream

What is wind power?

Renewable source that uses wind to generate electricity, rotating blades transfer KE to generator, which converts it to electrical energy

What are the advantages of wind power?

• Renewable, sustainable

• No GHGs

• Reduces dependence of fossil fuels

• Creates jobs in manufacturing

• Small/large scale

• On land/offshore

  • Cheap to run

What are the disadvantages of wind power?

• Wind not constant so availability fluctuates

• Electricity generation depends on wind speed and consistency

• Visually intrusive

• Wind farms requires large areas of land

  • Birds may collide with turbines, impacting on local wildlife populations

What is wave and tidal power?

The rise and fall of wave/tide can turn turbine and generate electricity

What are the advantages of wave and tidal power?

• No pollution

• Reliable and can produce a large amount of electricity

• Renewable

  • Useful for small islands

What are the disadvantages of wave power?

• Expensive to build and maintain

• Damages fragile habitats

• Very few suitable locations

  • Technology not advances yet for large scale production

What is geothermal energy?

Caused by heat that is generated from within the Earth. water into steam, which turns turbine and generates electricity (for homes)

What are the advantages of geothermal energy?

• Renewable

• Reliable source of energy

  • Geothermal power stations are small compared to nuclear/fossil fuel power stations

What are the disadvantages of geothermal power?

• Few locations suitable so small scale only

• Can result in release of GHGs underground

  • Expensive to build and maintain

What is nuclear energy?

Energy stored in the nucleus can be released when nucleus splits - fission. Produces steam to turn turbines to generate electricity

What are the advantages of nuclear energy?

• No pollution into atmosphere

• Nuclear reactors are safe

• Can generate electricity on large scale

• Small amounts of uranium needed

• Reduces reliance on fossil fuels

• Increases energy security

What are the disadvantages of nuclear energy?

• Uranium is finite

• Produce radioactive waste - stored for thousands of years

• Safe ways of storing radioactive waste expensive

• If accident occurs, radioactive waste can leak out and spread