GCSE Design and Technology AQA (8552) Unit 2: Energy Generation

Fossil Fuels

• Fossil fuels are formed from the fossilised remains of plants and animals over millions of years
• Coal, oil and gas are extracted through mining and drilling
• Fossil fuels are considered a finite resource as they take a few million years to form, and humans are using them significantly faster than the environment can replace.
• They are relied upon for power generation because they are effective and they are a cheap source of energy
• Extraction of fossil fuels can disrupt the environment, especially open cast mining.

Energy Generation

• Fossil fuels can be burned to superheat water under pressure, which in turn, drives turbines
• Chemical energy from fuel is turned into heat, in the form of superheated steam
• The steam drives turbines, converting heat to kinetic energy
• Kinetic energy drives the shaft which spins an electricity generator, converting kinetic energy to electricity
• The electrical energy is transferred to the National Grid by pylons, where it is used.

Fracking

• Fracking involves drilling into layers of shale rock deep in the earth to release pockets of gas
• Water, sand and chemicals are injected into a well in order to force gas up
• The water pressure creates fissures in the rock which open up areas with gas
• Sand stops the fissures from closing up, and allow the gas to flow into the well pipe
• Chemicals can contaminate nearby water tables used for drinking…