Energy Sources

• Reasons for demand for energy is rising

  • increasing population size
  • increasing industrialization and urbanisation
  • improvements on standards of living and expectations
• Non-renewable - an item or resource that exists in a finite amount that cannot be replaced
• Renewable - an item or resource that will not be used up or can be replaced
• Non-renewable energy sources

  • oil
  • coal
  • natural gas
  • nuclear power
  • non-renewable as the material (uranium) it uses is only available for limited supply
• Renewable energy sources

  • geothermal
  • hydroelectric
  • tidal
  • wave
  • wind
  • solar
  • biofuels e.g. bioethanol, biogas and wood
  • wood can be replanted
• Nuclear fuels last for centuries and are a good replacement for fossil fuels, but the source material (uranium) is limited
• Biofuels may become limited, but it can be renewed by replacing the cut-down trees with new ones to obtain bioethanol and wood

  • Biogas can be obtained by recycling waste products
• Electromagnet induction - a process used for generating electricity that uses the movement of a metal coil and a magnet

  • Most electricity is generated by electromagnetic induction
  • Turns kinetic energy into electrical energy
• Different components in generating electricity:

  • Turbine - a machine, often containing fins, that is made to revolve by gas, steam or air (it is connected to a generator and rotates the coils)
  • Generator - a machine that converts mechanical energy into electrical energy
• Turbines are designed to provide the rotary motion needed in the generator

  • done by passing a stream of gas or liquid causing the shaft to move
• Simple electricity generation system

  • heat source heats up the water and it is converted to steam
  • steam passes through the blades of the turbine causing them to move
  • the rotation on the shaft causes the copper coils in the generator to move, producing electricity
  • electricity is transferred by the conductive wires to the light bulb
• Simple electricity generation system

  A) steam

  B) boiler

  C) burner

  D) turbine

  E) shaft

  F) generator

  G) wire

  H) bulb

  
• Burner - a receptacle used to hold fuel as it is burned
• Boiler - a vessel used to heat water to convert it into steam
• Efficiency of the turbine can be increased by fitting more blades or increasing the flow of gas or liquid that causes it to move by pressurising them
• Nuclear power:

  • Uranium, a radioactive element, releases huge amounts of energy when nuclear fission (splitting of the atom) occurs.
  • This energy is used to heat the water, produce steam, and rotate the turbines.
• Fossil fuels, biofuels, nuclear and geothermal power - these produce a massive amount of energy during combustion that is used to heat water and convert it into steam, which drives the turbine
• Wind, wave tidal and hydroelectric power - used to turn a turbine directly without the need to produce steam first
• Geothermal power:

  • Cold water is pumped under pressure into a layer of hot rocks
  • The rocks heat the water
  • The hot water returns to the surface under pressure and heats the second supply of water using a heat exchanger
  • The steam produced in the second supply moves the turbine, generating electricity
  • Water can be reused in the system to continue the process
• Geothermal power

  A) pump

  B) turbine

  
• Wind power:

  • Wind turbines have shafts (blades) that rotate due to wind
  • Gearbox maximises the rotation of the shaft as it enters the generator
  • Brakes slow down or stop the rotor in very windy conditions, preventing damage to the blade
  • As the turbine rotates, the generator produces electricity
• Wind power:

  A) generator

  B) grid connection

  
• Solar power - harnessing energy rfom sunlight

  • Uses photovoltaic cells that produce a small electric charge when exposed to light
  • A bank of cells organised into solar panelsand a group of panels organised into a solar array produces a significant amount of electricity compared to one cell
  • Advancements can make them far more efficient
• Tidal power - use of tides (natural change in sea levels) to generate electricity

  • Uses sea or large rivers
  • Uses the natural rise and fall in the level of water in an area
  • When the levels drop, water is held back by a tidal barrage
  • tidal barrage - a small dam that releases water back through a turbine
  • Tidal barrage generates electricity using a generator
  • Amount of power generated is dependent on the change in tide level throughout the day
• Wave power - use of changes in the height of a body of water to generate electricity

  • Uses sea or large rivers
  • also uses turbine and generator to generate electricity
  • uses the smaller differences in water levels that are caused by wind
  • power is produced by channeling the energy of waves at sea not tides
  • not limited to the regular pattern of the tides
  • electricity generation may stop when calm weather conditions mean that there is little or no wave production in an area
• Economic factors (1):

  • plentiful supply and ease of access
  • supply of energy is expensive - especially where the demand is increasing and the supply is limited
  • high demand fuel and short supply of fuel will cause the price to rise
  • a country with its own fuel supply can use their own sources rather than importing other sources - much cheaper
• Economic factors (2):

  • countries may have naturally occuring sources e.g. high amounts of sunlight, heat from underground rocks
  • some countries face an economic barrier that prevents them from using certain energy sources
  • cost of investing in technology might prevent a country or region developing solar power even though it has a plentiful supply of sunlight
• Social factors (1)

  • impact of different fuel sources will depend on the local area and the industry
  • mining or drilling an area might mean land is no longer available for agricultural use but it might mean greater local employment
  • increase in industry locally might mean businesses are supplied with the needs of the energy business and its workers
  • development of large scale products could provide improvements to the local infrastructure e.g. roads, supply of mains water and electricity, healthcare and schooling
• Social factors (2):

  • energy business could cause displacement of communities - the land in a valley is flooded due to dam construction
  • development of new technologies might bring new manufacturing opportunities - might seem as a disadvantage for those working in a sector that then starts to decline
• Social factors (3):

  • development of new energy sources can change political relationships and trading patterns between 2 nations e.g. developing a renewable energy source means that a country is less dependent on oil, reducing oil trade
  • investment in energy sources might have health effects for the local population e.g. dust from extraction, noxious fumes from combustion, risk of radiation from nuclear power
• Environmental factors (1):

  • biofuels will produce carbon dioxide when combusted but the growth of the plants will use carbon dioxide during photosynthesis
  • fossil fuels are a major contributor to CO2 in the atmisphere
  • pollution - spillage of fuel e.g. oil spills in the ocean, damage to wild life, burning fuels can produce toxic gases and waste products
• Environmental factors (2)

  • changes to the ecosystem - extraction of fuels from underground can destroy habitats for a range of animals or their food sources, renewable sources can cause problems e.g. damming a river can affect ability of fish to breed
  • visual impact - nature of the landscape can be changed e.g. large areas of solar panels or wind turbines impact an area’s natural beaty
• Fossil fuels

  • Advantages
  • Plentiful supply in some locations.
  • Extraction provides jobs
  • Existing technology: the fuel is available for most countries to use
  • Disadvantages
  • Carbon dioxide and toxic gases when burnt (impacting on climate change)
  • Extraction causes damage to local area
  • Limited supply: prices will rise as the supplies get smaller
• Nuclear power (using uranium)

  • Advantages
  • Does not produce carbon dioxide (impact on climate change)
  • Small amount of fuel produces large amounts
  • Power plant employs lots of people
  • Disadvantages
  • Risk of radiation leakage (impact on human health and environment)
  • Waste products cannot be recycled as radiation of energy active for centuries Power plants employ lots of people
  • Limited supply
• Biofuels

  • Advantages
  • A renewable source -bioethanol and wood are both obtained from growing plants, biogas from the recycling of waste products
  • Growing more plants uses carbon dioxide
  • Potentially a plentiful supply
  • Disadvantages:
  • Carbon dioxide and other toxic gases produced when burnt
  • A lot of land is needed to grow crops for fuel
  • Potential removal of natural ecosystems to grow crops
• Geothermal power

  • Advantages
  • Doesn’t produce carbon dioxide
  • Water can be reused for other purposes
  • Disadvantages
  • Can be expensive to install
  • Only certain areas have suitable conditions
• Hydroelectric power

  • Advantages
  • Doesn’t produce carbon dioxide
  • Tidal movements doesn’t depend on weather conditions
  • Disadvantages
  • limited to coastal areas
  • impacts on tourist industires and local fishers
• Wave power

  • Advantages
  • Doesn’t produce carbon dioxide
  • A renewable source of power
  • Disadvantages
  • Limited to specific areas
  • Currently not very efficient, so large amounts of resources are needed
• Solar power

  • Advantages
  • Doesn’t produce carbon dioxide
  • Sunlight isn’t a limited resource
  • Disadvantages
  • Only efficient under certain weather conditions
  • Generation only occurs in daylight hours
  • Visual impact and potential damage to local ecosystems
• Wind power

  • Advantages
  • Doesn’t produce carbon dioxide
  • Uses a renewable resource
  • Disadvantages
  • Not all locations are suitable
  • Generation only occurs in certain conditions (at certain wind speeds)
  • Visual impact
  • Uses a large area