The big picture

We all rely on energy in our daily lives, from using electronic devices (such as the computer you are using to access this online book) to transport. How much energy (e.g. in the form of electricity and fossil fuels) do you use on average each day?

What are the energy resources used in your area and what reasons determine this choice?

As discussed in the previous topic 6, global consumption of energy has increased with:

• Growth of population.
• Industrial development.
• Increase in affluence of human societies.

Most of our energy requirements have been met through the use of fossil fuels. Detrimental effects have included:

• Urban air pollution including photochemical smog.
• Acid deposition.
• Increase in greenhouse gases contributing to climate change.

Figure 1. Transport of fossil fuels such as oil also increases risk of oil spills.

Other potential sources of energy production include nuclear power and renewable energy. Development of technology resulted in the emergence of the first commercial nuclear power stations during the 1950s. However concerns over disposal of nuclear waste and accidents such as Chernobyl in 1986 and Fukushima in 2011 has curtailed the growth of nuclear power.

In recent years the pursuit of less polluting methods of energy production has seen significant investment and growth in renewable sources of energy such as solar and wind. Each source of energy has its own advantages and disadvantages.

Figure 2. Global investment into renewable energy 1995-2007.

In order to ensure reliable future supplies, many nations are attempting to:

• Diversify their sources of energy.
• Reduce growth in consumption through energy conservation strategies.

http://uk.oneworld.net/penguin/energy/

Review of resources

Resources are referred to as natural capital. Resources are classified as renewable, replenishable or non-renewable. If properly managed, resources are forms of wealth that can produce “natural capital” indefinitely in the form of valuable goods and services.

The three classes of natural capital are:

• Renewable natural capital is a biological resource that is dependent on the sun's energy for renewal. Examples: timber, fruit crops
• Replenishable natural capital is a non-living resource that is dependent on the energy of the sun for their replenishment. Examples: wind, solar
• Non-renewable natural capital is a resource which cannot be replenished within a timescale similar to the rate that they of extraction/exploited from the environment Example: fossil fuels, unsustainable logging.

Fossil fuels

Globally most of the energy we use for electricity generation, transport and heating comes from fossil fuels which comprises of coal, oil and natural gas. Our reliance on fossil fuel is expected to continue in the near future, with overall use increasing to meet rising energy demands.

Make sure that you analyse any table or graph presented in terms of proportion, ratios, percentages and absolute numbers depending on the command word in the question.

Figure 1. Global consumption of energy by fuel type 2014.

Fossil fuels are formed from dead plants and animals under pressure over millions of years. They provide a finite source of energy and if use continues they will eventually become exhausted.

Coal

In addition to the above advantages and disadvantage of using fossil fuel, other important factors about coal include:

• It is a hard solid that contains carbon, hydrogen, oxygen, nitrogen and sulphur compounds.
• Is the most abundant fossil fuel.
• Is found in many places around the world with the largest reserves in China, USA, Russia and India. The top producers of coal include China, USA and India.
• Usually obtained from either:
  • Deep mines.
  • Open mines.
• Mining can be hazardous to human health, for example, exposure to coal dust can lead to industrial bronchitis and coal workers pneumoconiosis (black lung disease).
• Mining is a very dangerous occupation. Thousands of deaths each year are caused by mining accidents.
• Coal mining can contaminate aquatic systems with toxic metals (e.g acid mine drainage).
• Burning of coal produces ash containing metal oxides and alkali requiring disposal.

Figure 2. Miners working in difficult conditions underground with high exposure to coal dust.

Oil

Additional key features of oil include:

• It is usually pumped from underground reservoirs. Offshore extraction resulted in the Gulf of Mexico Deepwater Horizon oil spill.
• Drilling can pollute underground aquifers.
• The largest reserves are located in Saudi Arabia, Venezuela, Canada, Iran and Alaska. The top producers of oil include Saudi Arabia, Russia and US.
• It is transported by tanker ships, pipes, trucks and train. This can also result in accidental oil spills affecting marine life.
• Oil refineries separate the oil out into different products that include:
  • Residue containing bitumen used in road building.
  • Fuel oil for ships and power stations.
  • Diesel for cars and lorries.
  • Kerosene used by aircrafts.
  • Gasoline (petrol) for cars.
  • Various additional chemicals used to make plastics and fertilizers.
• Waste from the refinery processes includes slurry containing metals and toxic compounds.
• Oil produces less emission of carbon dioxide, NOx, SO2 and particulates than burning coal but significantly more than natural gas.

Figure 3. Oil refinery that separates crude oil out into different components.

Natural gas

Additional features of natural gas include:

• It comprises of mostly methane but also ethane, butane, propane and pentane.
• The largest reserves are found in Russia, Iran, Qatar and Turkmenistan. The top producers of natural gas include the US, Russia and Iran.
• Leaks can be difficult to detect because natural gas is odourless, colourless and tasteless (hence hydrogen sulphide which smells of rotten eggs is often added to aid leak detection).
• It has a lower nitrogen and sulphur content than oil or coal resulting in less harmful emissions. Overall it produces less carbon dioxide, NOx, SO2 and particulates than other fossil fuels.
• Recent expansion of hydraulic fracking to obtain shale gas (e.g. in U.S shale gas contributes to about a third of overall gas production). Fracking can potentially:
  • Contaminate groundwater.
  • Pollute surface waters with waste products.
  • Contribute to seismic activity.

Figure 4. Fracking process in which under pressure, water, sand and chemicals are used to extract gas from otherwise unavailable sources.

Watch the following video by In a nutshell - Kurzgesagt on 'Fracking explained: opportunity or danger':

Click here for video

Nuclear power

Most nuclear power plants are concentrated in North America, Europe and parts of Asia. In France about 75% of all of the electricity generated is from nuclear power compared to about 20% in the USA and 2% in China.

Figure 1. Nuclear power in the world 2014.

Power generation

Uranium is mined in a number of countries around the world (e.g. Kazakhstan, Canada, Australia, USA and Namibia). The ore is processed and purified prior to forming fuel elements that are used in a nuclear reactor. Neutrons start a chain reaction in which energy is produced from the splitting of uranium atoms, also referred to as nuclear fission. The heat generated is used to turn water into steam. The steam is feed through a pipe to a steam turbine. The steam rotates the blades within the turbine that generates electricity.

Figure 2. Neutron hits a fissionable nucleus such as uranium atom causing nuclear fission and a chain reaction.

Figure 3. Nuclear power plant, energy from the core reactor is used to heat water to drive a steam turbine to produce electricity.

Used nuclear fuel can generate a lot of heat and contains highly radioactive material hence is usually stored in lead containers immersed in cooling ponds.

Radioactive waste management

Radioactive waste is generated at all stages of the nuclear fuel cycle. The time it takes for radioactive material to decay varies from fractions of seconds to thousands of years. Low level waste is often filtered and then disposed of into the environment e.g. through atmospheric emissions or wastewater discharge. Solid waste such as paper towels and gloves used on site are buried underground. Other waste material is stored in lead covered stainless steel container. The main route of disposal elected by most countries is underground repositories. Concerns over this include potential:

• Dispersal of radioactive materials caused by:
  • Chemical corrosion of the container.
  • Microbial action.
  • Geological change e.g. earthquake or volcanic activity.
  • Human activity e.g. terrorism.
• Contamination of groundwater.

Watch the following video that provides an overview of the development of nuclear power and how it is used to generate electricity ‘Nuclear energy explained: How does it work?’ By In a nutshell – Kurzgesagt:

Nuclear accidents

With the use of nuclear power, there is always a risk of nuclear accidents. Built in safety features in modern plants attempt to reduce these risks. Two major nuclear accidents include Chernobyl and Fukushima are discussed here.

Chernobyl, Ukraine

Figure 4. Location of Chernobyl in Ukraine.

On the 26 April 1986 operators at the Chernobyl nuclear reactor overrode a safety mechanism during a routine test. An unexpected power surge led to a fire breaking out in the reactor and an explosion that blew the roof off. This resulted in the release of a radioactive plume that was blown west by prevailing winds over Europe. In addition to radioactive contamination in the Ukraine, Russia and Belarus, wind and rainfall patterns resulted in high levels of contamination in Norway, Sweden and parts of the UK.

Following the explosion, helicopters were used to drop material into the reactor to extinguish the fire and prevent more radioactive material escaping into the atmosphere. Tunnels were dug beneath the reactor and filled with concrete to isolate the reactor from aquifers and surface waters. Members of the army were used to clear highly radioactive material.

The official death toll of the accident was 31, although there is still great debate about the number of people that have died as a consequence of exposure to radioactive material. There has been an increase in the number of children born with birth defects and a rise in the number of cancer cases particularly thyroid cancer. More than 350,000 people from the contaminated region were relocated.

Watch the following video which provides an overview of the Chernobyl accident, ‘Chernobyl: The world’s worst nuclear disaster’ by TestTube news.

Fukushima Daiichi nuclear accident

Figure 5. Location of Fukushima Daiichi, evacuation zone and the epicentre of Tōhuku earthquake responsible for the tsunami.

The Tōhuku earthquake and tsunami on 11 March 2011 caused high waves to breach the seawalls near the Fukushima nuclear power plant. Seawater flooded the nuclear power plant including the main generator and the rooms containing the emergency backup generators. With the resulting failure of all the generators used to circulate cooling waters, the reactors overheated resulting in meltdown and production of gases causing a number of explosions. This released radioactive material into the atmosphere.

Evacuation of people in the region reduced exposure levels. No direct deaths were attributed to the Fukushima accident although the number of thyroid cancer cases in the area has risen. The Tōhuku earthquake and tsunami was one of the most powerful ever recorded and estimated to have caused about 18,500 deaths.

Figure 6. Impact of the Tōhuku tsunami which devastated the eastern coast of Japan.

The Fukushima Daiichi accident influenced public opinion around the world about nuclear power. After the accident Germany closed eight out of 17 of its nuclear power reactors.

Advantages and disadvantage of nuclear power

Nuclear power is sometimes referred to as a ‘clean’ energy source because it produces few emissions that contribute to GHGs, acid rain or urban pollution. Table 1 outlines some of the advantages and disadvantages of using nuclear power.

Some advocators of nuclear fuel (including those with a technocentric view point such as a cornucopian) argue that future technological development will:

• Provide a solution to the radioactive waste created.
• Provide a replacement for uranium as a fission material that produces less radioactive waste and is more abundant.

International-mindedness

Although the use of nuclear power is often decided at a national level the impacts of a nuclear accident could have regional or global implications.

Renewable energy I

Renewable sources of energy include solar, wind, hydropower, biomass, geothermal, wave and tidal.

Advantages of using renewable energy compared to fossil fuel sources include:

• Improvements to local air quality e.g. production of less primary pollutants such as particulates, SO2, NOx and secondary pollutants such as ozone.
• Reduced GHG emissions e.g. CO2.

Developing renewable energy can also provide employment opportunities and improve the energy security of a country.

The use of renewable energy although on the increase is relatively gradual. Factors which could accelerate growth include:

• Decline in fossil fuel reserves forcing prices up.
• Technological developments improving efficiency of renewable energy and capital cost.
• Governmental support through economic incentives e.g. subsidies.
• Increase awareness of environmental impact of using fossil fuels e.g. climate change.
• Need to meet agreed international targets e.g. reduction in carbon dioxide emissions.

ADVANTAGES & DISADVANTAGES OF RENEWABLE SOURCES OF ENERGY.

Solar power

The amount of solar radiation that reaches the planet surface depends on a range of factors including:

• Tilting of the earth reflecting the season e.g. highest radiation occurs during the summer months.
• Amount of cloud cover.

Figure 1. Sunlight hitting the earth at midday on a spring or autumn day. The density of sunlight per unit land area in Cambridge (latitude 52°) is about 60% of that at the equator in Nairobi.

Two main types of solar panels include:

• Solar thermal panels used to heat water and buildings.
• Photovoltaic panels used to convert sunlight to electrical energy.

Solar thermal panels

These can be fitted onto the roof of buildings and can be used in a number of different ways e.g.:

• Air can be warmed and then passed back into the building.
• Water can be heated and then either be:
  • Stored until required (e.g. hot water for washing and bathing).
  • Stored where it can transmit its heat (e.g internal wall). The heat from the water is gradually released during the night helping to maintain a more even room temperature.

Figure 2. Use of solar panels to heat the building (underfloor heating) and swimming pool.

Photovoltaic panels

The efficiency of photovoltaic panels typically ranges between 10 to 20%. Cost of production and installation is relatively high, although running costs are relatively low. The manufacture of solar panels produce pollutants such as carbon dioxide but once set up and running there are no emissions. Panels called heliostat can track the movement of the sun, maximizing the amount of electricity produced.

Watch the following video on ‘How photovoltaic solar cells work’ by adriotsolar:

Figure 3. Desert Sunlight solar farm, California (capacity of 550MW) one the world’s largest solar parks.

Wind power

Windmills have been used historically to pump water or drive mechanical machinery e.g. for grinding grain to produce flour. Wind turbines that produce electricity are called aero-generators.

They usually have fewer blades than the traditional windmill and hence require stronger winds to get started. In northern hemisphere countries such as the UK, higher energy demand in the winter months is matched by greater number of windy days and higher wind speeds.

Figure 4. Growth in global wind power.

Often the windiest and therefore best sites are located on the top of hills where they could be considered to be visually intrusive and a blot on the landscape. Opponents of wind power also cite noise produced and interception of bird migratory routes as issues. These aspects can be considered when determining where to site wind power to minimize any potential impact.

Watch the following video ‘Wind Power’ on how wind power works and some of its pros and cons by NOVA PBS:

Offshore wind power

Wind farms can also be sited offshore where winds are often stronger than on land. Although noise becomes less of an issue at sea, other areas of concern include:

• Visual impact on the seascape, especially when sited near the coast.
• Corrosion of the aerogenerator.
• Potential impact of vibrations from the aerogenerator on sea life.
• Potential impact on seabirds.
• Disruption to shipping routes.
• Reduced fishing grounds for fishermen.

Hydropower

Hydropower is currently the most used renewable source of energy. The energy obtained from the movement of water has historically been used to drive a variety of machinery from grinding flour to sawing wood. Hydroelectric power (HEP) is produced when flowing water drives turbines connected to a generator which converts mechanical energy into electrical energy.

HEP schemes are often also associated with building reservoirs for water resources. The dam wall built to maintain water in the reservoir also raises the height of the water prior to reaching the turbines, which increases the amount of power generated from the falling water. The environmental and social impacts of daming a river are discussed in subtopic Access to fresh water.

Figure 1. World’s largest hydro-electric dam scheme - Three Gorges Dam along the Yangtze River, China.

The largest producers of hydropower are China, Brazil and Canada. Paraguay generates most of its electricity from hydropower via the Itaipu Dam it shares with Brazil and the Yacyretá Dam it operates with Argentina.

Small scale hydropower schemes have fewer environmental impacts than large scale schemes. Watch the following video about a micro hydropower scheme in Nepal.

You should be able to outline of the advantages and disadvantages of a micro hydropower scheme over a large scale scheme or other forms of energy.

Geothermal energy

This is energy from the interior of the earth that sometimes leaks through faults and fractures to the surface of the earth. Groundwater heated by geothermal energy can reach the earth’s surface as hot springs and geysers.

Figure 2. Geothermal energy escaping from the earth as steam.

Geothermal energy can be used to heat buildings and generate electricity.

Enhanced geothermal systems can also be created in which holes are drilled into heated areas called ‘hot dry rock’ through which pressurised water is passed and collected as steam used to drive turbines that generate electricity.

The following short video provides an explanation of enhanced geothermal systems (EGS)

Energy security

Definition

The International Energy Agency defines energy security as 'the uninterrupted availability of energy sources at an affordable price'.

Energy resources are not distributed equally around the world. Some regions have large fossil fuel deposits whereas other areas have few. This can lead to conflict over ownership and territorial rights.

Some countries such as Saudi Arabia, Russia and Canada are major exporters of fossil fuels. Also nations which produce surplus electricity can sell this to other countries e.g. Paraguay produces electricity from hydropower and exports surplus to its neighbours Brazil and Argentina. Some countries rely on imports to meet their needs i.e. when consumption exceeds national production levels. This reliance can make them vulnerable to political changes in the exporting nation.

Figure 1. Differences in production and consumption of energy in different countries.

Energy security depends on:

• An adequate supply of energy which matches demand.
• Reliable supply, that is not interrupted e.g. by conflict.
• Affordable supply to ensure access to all.

A reduction in energy supplies can affect everyday activities, transport, industry and therefore the national economy. Hence the availability of energy affects national security.

Threats to energy security include:

• Political instability and /or conflict in exporting country.
• Accidents or natural disasters e.g. Fukushima accident.
• Risk of terrorist attacks on source or supply infrastructure.
• Exhaustion of resource.

Risk of these threats can be reduced by:

• Reducing imports and becoming more self-sufficient in energy supply. This may involve:
  • Diversifying sources of energy, increasing alternatives to fossil fuels such as renewable sources.
  • Exploiting indigenous resources.
  • Reducing demand by increasing energy efficiency and energy conservation measures.
• Reducing reliance on one or two exporting countries and using multiple exporters i.e. spreading out the risk.

Examples of increasing energy security

Governments around the world have recognized the importance of improving energy security and are attempting to address this issue. Below are two such examples.

Iceland

Iceland is an active volcanic island in Northern Europe. Its energy policy capitalizes on its abundant natural resources with the aim of using renewable resources to become energy independent by 2050.

Figure 2. Energy sources in Iceland, 2014.

Most of Iceland’s electricity already comes from renewable energy, approximately 71% from hydropower and about 29% from geothermal power. Most homes are heated via geothermal power. Iceland has in recent years also invested in wind power, further diversifying its portfolio of renewable energy sources.

Fossil fuels are used for vehicles, boats and some industrial purposes. Iceland’s aim is to replace imported fossil fuels with hydrogen fuel cells and electric vehicles.

Figure 3. Hydrogen fuel cell in which electricity is generated from reaction between hydrogen and oxygen forming water.

Watch the following video ‘Geothermal energy in Iceland’ by Ken Schreiner, which discusses how renewable energy is harvested in Iceland:

United States of America

The USA is one of the largest consumers of energy in the world. Currently the majority of its energy comes from fossil fuels.

Figure 4. Energy sources in the USA, 2014.

The US uses large amounts of fossil fuels. Despite being a major producer of fossil fuels, the US is a net importer of oil. In 2014, the US imported about a quarter of the oil it uses from over 40 countries which include Canada, Saudi Arabia, Mexico, Venezuela and Iraq.

In order to reduce reliance on other countries for energy, the US is attempting to become more energy independent by:

• Increasing indigenous production levels of fossil fuels e.g. expansion in shale gas extraction.
• Diversifying energy sources to include renewables e.g. wind and solar.
• Increasing energy efficiency e.g. improved fuel efficiency in vehicles.

The Clean Power Plan announced in 2015 aims to reduce greenhouse gas emissions by 32% of 2005 levels by 2030 through:

• Reducing emissions from coal power station.
• Increasing renewables including wind and solar power.

General trends in the US include:

• Increase energy conservation to reduce demand.
• Increase indigenous production of fossil fuels and reduced oil imports.
• Reduction in use of coal and oil but increase in use of less polluting natural gas.
• Continued use of nuclear power.
• Increase in renewable energy sources e.g. wind, solar and biomass.
• Investment in low carbon emission technologies e.g. electric vehicles.
• Overall increase in the range of different energy sources.

Figure 5. LED lights use up to 90% less energy than traditional bulbs.

Factors affecting energy choices

Factors that determine the choice of energy sources include availability, sustainability, scientific and technological developments, cultural, political, economical and the environmental impact.

Availability

The availability of an energy source will depend on the location that determines:

• Geology e.g. some countries have an abundance of fossil fuels or relatively easy access to geothermal power.
• Topography e.g. hillsides suitable for wind power and rivers for hydropower.

Figure 6. Aerogenerators located on a hill.

Sustainability

Many countries are beginning to consider energy choices over the long term and investing in renewable resources rather than non-renewable fossil fuels which will eventually run out.

Scientific and technological developments

Developments in science and technology are increasing the choices of affordable alternative sources of energy e.g. technology development has decreased the cost of photovoltaic panels. Scientific discoveries may provide new options for the future.

Cultural attitudes

Some communities have a more nature centered environmental value system and are more proactive in changing their behaviour to reduce energy use and moving to less polluting energy sources.

Politics

Some national governments have a greater political will than others to improve long term energy security and make dramatic changes to policies that alter energy sources and individual lifestyles. Governments often make decisions that reflect changing values of the population they represent. Governments may also be responding to international agreements including environmental emission targets.

Figure 7. Protest against nuclear power in Berlin, Germany.

Economics

Energy sources need to be economically viable as they must be affordable to all to ensure full access. The economic wealth of a country may limit the choice of energy source e.g. nuclear power stations are expensive to build.

Environmental impact of energy resource

There is a general drive by many countries to reduce greenhouse gases emission such as carbon dioxide and hence a move away from the use of coal and oil and toward less polluting resources such as wind and solar.

International-mindedness

Many global factors influence energy security. Hence it could be viewed as a global rather than just a national issue.

Watch the following video ‘300 Years of fossil fuels in 300 seconds’ by postcarboninstitute:

Biogas is naturally produced when organic matter decomposes in anaerobic conditions. The methane produced can be harnessed on a range of scales and used to burn as a cooking fuel or to create electricity. Suggest why methane is still being allowed to escape directly into the atmosphere instead of being harnessed as a fuel.

Tip: This is a question of scale of investment, public perception, infrastructure availability, government priorities etc. It also relies on you having an understanding of decomposition and the nitrogen cycle.

Biofuels - the answer or the problem? Discuss

Tip: Exam plan