Generating Electricity

• Wind
• Wave
• Solar
• Geothermal
• Tides
• Food
• Hydroelectric
• Biofuels
• Never run out
• Damage the environment less than non-renewable sources
• Don't provide much electricity -> unreliable

• Coal
• Oil
• Natural gas
• Nuclear fuels (uranium and plutonium)
• They will all run out one day
• All damage environment
• Provide most of our electricity

1. The fossil fuel is burned to convert chemical energy into thermal energy

2. The thermal energy is used to heat water to produce steam

3. The steam drives a turbine, converting thermal energy into kinetic energy

4. The turbine is connected to a generator, which transfers kinetic energy into electrical energy

• Involves wind turbines
• Each wind turbine has its own generator inside it, so electricity is generated directly from the wind turning the blades, which turn the generator
• No pollution
• Spoil landscape, but no permanent damage to landscape once turbines are removed
• Can be noisy
• Unreliable
• Initial costs are high

• Often used in remote places to power road signs and satellites 
• No pollution
• Very reliable in sunny countries but only in daytime
• Still cost-effective in cloudy countries
• High initial costs but free energy and very low running costs
• Often used to generate electricity on a relatively small scale e.g. homes
• Often not practical or too expensive to connect to National Grid

• Requires flooding a valley to build a dam
• Rainwater is caught and allowed out through turbines
• No pollution
• Big impact on environment due to flooding of the valley -> rotting vegetation releases methane and CO2, loss of habitat, loss of villages, dams look unsightly when dried up
• Can provide an immediate response to an increased demand for electricity
• Reliable (except in times of drought)
• High initial costs, but no fuel costs and low running costs
• Useful on a small scale in remote areas

• 'Spare' night-time electricity is used to pump water up to a high reservoir
• Can be released quickly during periods of peak demand
• Doesn't generate electricity, only stores it when it has already been generated 

• Requires many small wave-powered turbines located around coast
• Waves provide an oscillating motion which can be used to drive a generator
• No pollution
• Spoils view and is a hazard to boats
• Unreliable as waves tend to die out when the wind drops
• High initial costs, no fuel costs and low running costs
• Useful for providing for small islands

• Big dams built across river estuaries with turbines in them
• Incoming tide fills up estuary to a height of several metres and drives turbines
• Water can be allowed out through turbines at a controlled speed
• Source of energy is gravity of Sun and Moon
• No pollution
• Prevents free access by boats, spoils view, alters habitats
• Reliable tides with accurate predicted height
• Good for storing energy
• High initial costs, no fuel costs and low running costs
• Can be only used in some suitable estuaries

• Only possible in volcanic areas with hot rocks near surface
• Source of energy is slow decay of radioactive elements e.g. uranium
• Free energy
• Can be used to heat homes directly without being converted to electrical energy
• Aren't many suitable locations for power plants
• High building costs compared to amount of energy gained

• Generate electricity the same way as fossil fuels
• Can also be used in cars
• Can be solids (e.g. straw, nutshells and woodchips), liquids (e.g. ethanol) or gases (e.g. methane)
• Can get biofuels from organisms that are still alive or from dead organic matter
• E.g. crops like sugar cane can be fermented to produce ethanol
• E.g. plant oils can be modified to produce biodiesel

• Mostly the same as a fossil fuel power station, but with nuclear fission
• Uses nuclear fission (with uranium or plutonium) to produce heat to make steam to drive turbines
• Nuclear reactors also have a boiler
• Has the longest start-up time of all power stations (compared to natural gas, which has the shortest time)