3.5 Energy

Global energy use

Why amount of energy being used in countries is increasing

• Increasing ownership of cars/vehicles

• More aircraft/flights

• Tourism is increasing

• More use of electrical appliances in the home

• Industrialisation

• Mechanisation/technological development

Why there is variation in the amounts of energy used in different parts of the world

• Variation in population size; Less/more people live there

• Variation in amount of energy resources; Some countries have more energy resources; e.g. oil, coal etc.

• Variation in availability of energy/electricity supply; available throughout the country

• Variation in affordability of energy supplies 

• Variation in technology; some countries use more electronic devices/home appliances

• Variation in industry; some countries are more industrialised/have more factories - Eg. manufacturing industry is likely to use large amounts of energy

• Variation in transport; Some countries use more transport/have more cars; Eg. car ownership is higher in MEDCs

• Variation in travel; Some countries travel more by plane/for leisure travel

• Impact of climate e.g. impact of air conditioning

Why there is relationship between GDP per person and use of electricity per person

• Electricity availability tends to increase with development

• Higher GDP will enable investment in power stations/supply infrastructure

• Countries with higher GDP likely to use energy/electricity in factories/workplaces

• Countries with higher GDP likely to use more home appliances

• In many countries with low GDP, many rural areas are not connected to grid

Renewable energy

• Geothermal power

• HEP

• Wind power

• Solar power

• Tidal power

• Wave power

• Biomass/biofuels 

• Fuelwood (main source of energy in developing countries)

Geothermal energy

Natural heat found in earth’s crust in the form of steam, hot water & hot rock.

Advantages 

• Low environmental impact

• Occupy small land areas

• Low maintenance costs

• Not dependent on weather conditions (wind/solar)

Disadvantages 

• Few locations where significant amount of geothermal energy can be generated

• Some of these locations are far from where the energy needs to be used

• Expensive to setup/install

• Total global generation is small

HEP

How hydroelectric power is generated

• Water held in reservoir/water stored behind dam

• Flows down slope/into water inlet/through control gate

• Turns turbine

• Turbine linked to generator/creates electricity

Why some parts of a country can generate large amounts of electricity from HEP

• Have lots of rainfall

• Mountainous / have steep slopes

• Experience periods of melting snow / ice

• Have large / fast flowing river(s) / waterfalls

• Have many places to build dams / reservoirs

• Have large areas of land which can be flooded / open space / sparsely populated

Factors influencing location of HEP stations 

• In mountainous areas/on steep slopes/drop in height

• Where it is easy to build dams/in a valley

• On/next to/close to (fast flowing) rivers

• Two lakes at different levels.

• In areas with high amounts of precipitation

• So water flow will be constant

• In areas where temperatures do not fall below zero for long periods of time

• So rivers/reservoir does not ice over

• Impermeable rock

• Firm foundations/hard rock/not prone to earthquakes

• In sparsely populated areas

• So there is less opposition

Drawbacks of using HEP

• Large dams have visual impact

• Affects aquatic life

• Deterioration in water quality

• Large areas of land may need to be flooded to form reservoir behind dam

• Submerging large forests without clearing can release methane (greenhouse gas)

Wind power

Why there is limited use of wind turbines for electricity generation in many countries

• Limited areas with high winds speed/winds not strong enough/winds don’t blow all the time/little wind

• Limited space available for siting of turbines/they need a large area

• Expensive building cost/cannot afford to build 

• Technology not available in all countries/lack of skills to build

• Only generate relatively small amounts of energy

Tidal & wave power

Advantages 

• Less visual impact/ Infrastructure is less obtrusive

• No greenhouse gas emissions

• No air pollution

• Has the potential to produce large amounts of energy

• Reliable (compared to solar/wind)

Disadvantages

• Few suitable sites

• Expensive to build and maintain

• Can affect marine ecosystems

Biomass

Advantages 

• Uses waste or biofuels (from crops) which regrow

• Available in most locations

• Cleaner emissions than petroleum-based fuels

Disadvantages 

• Air pollution

• Produces greenhouse gases/global warming

• Large areas of cropland used to produce biofuels; global food crisis

• Large amounts of water & fertilisers used to produce biofuels

• Expensive

• Low energy output

Fuelwood

Advantages 

• It is free 

• Does not require technology 

• Can be renewable if the trees are replaced

• No high technology equipment is needed to use the fuel

Disadvantages

• The use contributes to deforestation, soil erosion and desertification

• Amount of wood cut each year is greater than rate of replanting and regrowth

• Little wood left in many areas, so people have to walk larger distances to collect it

• Leads to indoor pollution, which leads to health issues from exposure to smoke. 

Opinions regarding development of renewable energy resources

Supporters argue:

• Low running costs // Low cost electricity once constructed

• Energy supply will never run out; Renewable/sustainable electricity produced

• No air pollution/gases/CO2; Away from land so no noise pollution (if in sea)

• Less likely to cause global warming

• Creation of employment for construction/maintenance

Opponents argue:

• Visual impact/can be seen for many miles

• Hotel owners may be worried about loss of tourism

• Noise pollution (wind turbines)

• Ecosystems disrupted by construction

• Birds flying into wind turbines // marine ecosystems disrupted by construction

• Loss of habitat

• Deforestation

• Loss of farming land/land can be used for other purposes (if on land) // Possible disruption to shipping / Fishing industry problems (if in sea)

• Only small amount of energy can be generated relating to initial cost

• Construction costs are expensive

• Energy will only be generated when sun is shining/doesn’t work at night // energy will only be generated when wind is blowing

Non-renewable energy

• Coal

• Oil

• Natural gas

• Nuclear energy

Renewable Vs. Non-renewable sources

Benefits for a country by using renewable energy rather than fossil fuels. 

• Renewable sources won’t run out // fossil fuels will run out/finite/not renewable

• Renewable sources don’t depend on imports/can export renewable energy

• Renewable sources have cheaper production/running costs // fossil fuels are expensive to produce/extract/import; Fossil fuels have high transportation costs

• Renewable sources don’t pollute atmosphere

• Renewable sources don’t emit CO2/greenhouse gases/don’t enhance global warming

• Renewable sources do not produce acid rain

• Renewable sources produce no waste products; less chance of oil leaks

• Renewable sources have benefits of multi-purpose schemes, eg. recreation/irrigation

Why renewable sources do not provide large amounts of energy in many countries.

• Many countries don't have physical conditions required for its generation

• E.g. not enough sunshine for solar power/not enough precipitation for HEP/inland location so wave power is not possible 

• Many countries cannot afford to develop them

• Cost of setting up is relatively expensive

• Many countries lack suitable technology/expertise

• Currently many countries are limited in the quantities of electricity which can be produced/most are small scale

• Infrastructure is geared towards fossil fuels

• Political preferences/e.g. preference for nuclear power

Nuclear power

Benefits

• Reduced reliance on imported fossil fuels

• Low production/running costs ; not vulnerable to fuel price fluctuations

• Does not produce air pollution/CO2/greenhouse gases

• Does not enhance/contribute to global warming

• Uses small quantities of uranium/raw material; produce large amount of energy from small amounts of uranium

• Uranium has no other uses 

• Large amounts of electricity can be generated

Drawbacks

• Concerns about radiation/meltdown/cancer

• Nuclear power stations could be damaged by earthquake

• Problem of disposing of nuclear waste

• Expensive to build/setup/construct 

• Political issues/government ideology

• Public pressure/opposition/protests/environmental awareness

• Risk of terrorism: some countries may be developing nuclear weapons