Topic 7.1 Climate change and energy production

7.1 Energy choices and security

Range of Energy Resources• Renewable

– Solar– Hydroelectric– Geothermal– Biomass– Tidal– Wave

• Non-renewable– Coal– Gas– Oil– Nuclear

Macro-scale(country-wide schemes contributing to the national grid)

Micro-scale(domestic or within small communities)

http://www.youtube.com/watch?v=Gz_L6KuqvFI

Range of Energy Resources• In 2004, global energy production was 500 exajoules (1

exajoule = 1 x 1018 J)• Approximately 80% of this was derived from fossil fuels• Fossil fuels provided the basis of the industrial revolution

(initially coal in Britain) and have been depended on ever since

• Oil is (was?) plentiful, portable and readily distilled into fractions such as petroleum and kerosene

• The advent of the combustion engine has cemented our dependence on oil

• Crude oil is extracted in combination with natural gas • The effects of fossil fuels on the environment were not really

considered until recently

Range of Energy Resources

Energy Consumption

Energy Consumption

• Per capita energy use in MEDCs is much higher than LEDCs

• The economies of MEDCs are based on high technology, high energy use, high fossil fuel use

• The economies of LEDCs traditionally have less available technology, greater dependence on natural resources (wood and biomass combustion), lower use of fossil fuels

http://www.youtube.com/watch?v=9qFKqDnGX0g

Energy Security

• This depends on supplies of energy that are:– Adequate– Reliable– Affordable– Provide a degree of independence

• Security in energy is also helped by increasing the efficiency of energy use

Energy Consumption

Energy Consumption

Energy Consumption• Non-renewable resources are generally cheaper than

renewables• Natural gas is cheap, relatively plentiful, can be burned

without refining, and is fairly clean (compared to other fossil fuels)

• Non-renewables generally have high capital costs, may be in the experimental stage and may be dependent on unreliable natural phenomena (wind, waves, sun etc.)

• The use of renewables will increase in the future as fossil fuels become depleted and less accessible – prices and taxes on polluting fuels will increase

Renewable Resources

• Do not usually release greenhouse gases (the exception is biofuels – which are in any case carbon neutral)

• Do not release NOx and SOx

• Small ecological footprint (biofuel cultivation is an exception)

• Generally expensive to exploit compared to fossil fuels (high capital and maintenance costs)

• Many technologies are still in the developmental stage

• Locations may be limited due to politics, local conditions and reluctance of local people (e.g. to live near wind turbines)

Advantages Disadvantages

Hydroelectric Power

• Reliable source of energy which can be switched on and off when needed

• Do not release NOx and SOx or greenhouse gases

• Creates artificial lakes which are used as recreational areas and reservoirs

• Cheap to run and maintain once built

• High capital costs• Large areas must be

flooded, displacing populations, destroying farmland and altering downstream ecosystems

• Increased downstream erosion rates

Advantages Disadvantages

Tidal Power

• Reliable source of energy

• Do not release NOx and SOx or greenhouse gases

• Cheap to run and maintain once built

• High capital costs• Locations are limited

by tidal range and shape of the coastline

• May interfere with navigation routes and wildlife

Advantages Disadvantages

Solar Power

• Reliable source of energy• Do not release NOx and SOx

or greenhouse gases• Cheap to run

• High capital costs and still being developed

• Locations are limited by availability of sunlight

• Storage of energy requires use of expensive batteries which may be polluting when disposed of

• May be expensive to maintain if things go wrong

• Components are expensive and their extraction may cause environmental damage

Advantages Disadvantages

Wind Power

• Reliable source of energy• Do not release NOx and SOx

or greenhouse gases• Cheap to run and maintain

(there is little to go wrong with a wind turbine)

• High capital costs and still being developed

• Locations are limited by availability of wind

• In many places there is reluctance to live near wind turbines due to noise and perception that they spoil landscapes

• May have effects on wildlife, especially birds

Advantages Disadvantages

Biofuels

• Carbon neutral• Do not release NOx and SOx

• Do not require existing technologies to be replaced for their use (i.e. the internal combustion engine)

• As portable as existing fossil fuels

• Produce greenhouse gases when combusted

• Large ecological footprint• Monoculture – therefore

often displace farmland and poor communities (also affecting food prices) or destroy virgin forest or other ecosystems

• Pesticide use represents further risk to the environment

Advantages Disadvantages

Combustion of Waste Materials

• Free resource (readily available and represents no depletion of natural capital – although waste should be minimised)

• May be burned directly or used as a source of methane from decomposition

• Burning of methane reduces the effect of a potent greenhouse gas that would otherwise enter the atmosphere

• Reduces pressure on landfill sites and waste transportation

• Produces greenhouse gases when combusted

• Results in the production of other harmful pollutants, especially dioxins

Advantages DisadvantagesRenewable or non-renewable resource?

Geothermal Energy

• Free and readily available resource

• Does not need to be converted to other forms of energy if used for heating

• May also be used to generate electricity

• Simple technology with low capital and maintenance costs

• Does not result in any form of pollution or have any visible effects on the landscape if used domestically

• Generally restricted to volcanic areas such as Iceland

Advantages Disadvantages

Fossil Fuels

• Cheap and plentiful (at least in the past)

• Existing technology for extraction and use

• Existing technology to control pollution (to some extent)

• Generally portable and can be delivered over long distances (coal is perhaps an exception)

• No other sources are able to generate as much energy at the present time

• Polluting (CO2, NOx, SOx)• Unsustainable (by definition,

supplies are limited)• As resources diminish it will

become more difficult and dangerous to extract them

• Accidents cause severe damage to ecosystems

• Open-cast mining causes habitat destruction on large scales

Advantages Disadvantages

Nuclear Power

• Does not produce greenhouse gases

• Existing technology • Produces large quantities of

energy• Extremely energy efficient (1kg

of uranium produces 20000 x more energy than 1kg of coal)

• By-products may remain radioactive for many thousands of years (there are unresolved problems of waste disposal)

• Radiation exposure results in death, severe forms of cancer and DNA damage (genetic effects are heritable)

• Accidents may cause severe damage to human health and ecosystems (there is high associated risk)

• Uranium is a scarce and non-renewable resource

• Planning is long and complex

Advantages Disadvantages

Factors Affecting Choice of Resource

MEDCs have much higher energy demands than LEDCshttp://www.youtube.com/watch?v=KtWoPZluI2E

Factors Affecting Choice of Resource• GDP has a large say in which resources can be used or developed• Historical basis (fossil fuel dependence is a hangover from the industrial revolution,

especially in those countries that participated in it)• Greater car use in MEDCs leads to greater dependence on petroleum• Low uptake of nuclear power in MEDCs due to perceived risk and problems of waste

disposal (France is an exception with 78% of electricity generation from nuclear sources; USA 20%)

• Fossil fuels are often a cheaper option due to existing, readily available, large-scale technology

• Humans are resistant to large-scale change especially when costs are stable (recession can change this perception)

• There is some reluctance to change to renewables due to the perception that they can spoil natural landscapes

• There is increasing awareness of the environmental damage caused by fossil fuel use which is leading to greater acceptance of renewable resource use

• Choice of resources is largely driven by government policy

Questions1. Outline the range of energy resources

available2. Evaluate the advantages and disadvantages

of two named renewable resources and two named non-renewables

3. Discuss the factors that affect the choice of energy resources by MEDCs and LEDCs