Energy production

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Where does energy come from?

Photo: Oliver Herold

Most of the energy on Earth originates from the sun. The sun’s energy is a product of nuclear reactions that occur when hydrogen atoms combine to form helium atoms. The energy travels to Earth through space as solar radiation. We experience the radiation as heat and light. Plants trap the solar radiation through the process of photosynthesis and store the light energy as chemical energy in carbon based molecules.

(Photo: http://commons.wikimedia.org/wiki/File:Sun.jpg)

What are fossil fuels?

Fossil fuels such as oil, coal and gas consist of fossilised remains of living things from many millions of years ago. The sun’s energy from millions of years ago is stored in these carbon-based fuels as chemical bonds. It is densely stored carbon!

Energy Production

Most of our energy in Australia comes from burning fossil fuels 

Burning fossil fuels releases the chemical energy stored in these carbon compounds as heat. The heat generated is used to drive turbines involved in creating electricity and turn motors that drive the movement of vehicles.

Note: you may want to explain or show a diagram about how fuels are converted into energy for the more practical or technical minded.

Energy and Climate Change

When we burn fossil fuels, we add Oxygen (O2)+ the fuel Carbon (C) = heat + carbon dioxide (CO2)

Photo: Freefotouk

Carbon dioxide is one of the chemicals released when fossil fuels are burnt.

Carbon dioxide is a greenhouse gas that is being released in huge quantities as we burn fossil fuels for energy. The worlds’ leading climate experts are saying these is very strong evidence to demonstrate that increasing levels of carbon dioxide in the atmosphere is causing an enhanced greenhouse effect that is causing climate change across the globe.

(Photo: http://www.flickr.com/photos/freefoto/2759629888/sizes/o/)

Greenhouse effect

We all know the feeling of warmth we get from standing in the sun. When the Earth absorbs energy from the sun, it radiates this energy back out as heat. Some of this goes back into outer space, and some of it is trapped by the atmosphere. The additional carbon dioxide in the atmosphere caused by burning fuel acts like a blanket to trap more of the heat that would normally go out into space. In a greenhouse for growing plants, the glass also acts as a blanket, trapping in the heat. This is why climate change is sometimes called the greenhouse effect.

Where does our energy come from?

Approximately 95% of electricity generated in Victoria currently comes from burning coal

Hazelwood power station

Most of the electricity used to power homes and businesses in Victoria is generated in the Latrobe Valley. Hazelwood power station in the picture is the oldest of these power stations and quite inefficient by modern standards. The coal that is burnt is brown coal and is mined near the power plant.

(Photo: Environment Victoria)

Burning coal

Creates heat

Boils water

The steam drives turbines

That turn generators

Which produce electricity

Coal is dug out of the ground, crushed, transported and used to boil water. The steam produced then drives turbines that generate electricity in generators. Energy is transformed into high voltage electricity which is then transmitted though power lines to homes and businesses. Energy is lost at each stage of this process. In Victoria , brown coal is burnt. As it has a very high water content, it is very inefficient source of heat. The black coal that is found in New South Wales is marginally more efficient.

Other energy sources

Some energy sources produce less CO2e.g. 

•Solar

•Wind farms

•Geothermal

•Wave

All energy sources have environmental impacts

Some of the details of this are covered in the optional unit on alternative energy.

Photo: Environment Victoria

Coal vs gas

efficiency of energy production

0%

20%

40%

60%

80%

100%

120%

coal gas

fuel type

%

energy required to producepow er at home

pow er used at home

Gas is the “cleanest” fossil fuel. This graph shows that gas is a far more efficient source of energy than coal. While gas can be a source of electricity generation, it is usually transported to the home to be burnt directly for energy for cooking and heating. Being a far more direct source of energy, more of the energy contained in the fuel is released for use in the home rather than wasted through energy conversion processes and transmittion.

Mauve - Power used in the homePlum – Energy wasted in producing electricity

The “lost” energy is the energy in mining, transport, power generation andtransmission. It takes a lot of energy to produce power from coal but it is cheap because there is some much coal about in Victoria.

Australia’s total emissionsSource: State and Territory Greenhouse Gas Inventories 2006, published by the Australian Government

(Emissions from extracting oil & gas)

(emissions from electricity generation)

Definitions of these sectors and other terms are as follows:> The ‘Stationary Energy’ sector is mainly greenhouse gas emissions from the production of electricity and other direct burning of fossil fuels in industries such as manufacturing and construction.> The ‘Transport’ sector comprises greenhouse gas emissions from air, road, rail and shipping transportation.> The ‘Fugitive Emissions from Fuels’ sector comprises the greenhouse gas emissions from the extraction and distribution of coal, oil and natural gas.> The ‘Agriculture’ sector comprises the emissions of methane and nitrous oxide only (that is, greenhouse gases other than carbon dioxide) from livestock, crops, agricultural and forest soils, and agricultural burning including the prescribed burning of savannas.> The ‘Land Use Change’ sub-sector includes greenhouse gas emissions from the conversion of forests to grassland and cropland.> The ‘Forestry’ sub-sector is carbon dioxide removals (that is, carbon sinks) from plantations established on agricultural land since 1990, referred to as ‘afforestation and reforestation’ in the Kyoto Protocol. See the Australian Greenhouse Office web site at http://www.greenhouse.gov.au for more detail.

Where does most energy get used at home?

Energy use in the home (source: DSE 2006)

59%

21%

10%

4%

3%

3%

space heating &cooling

water heating

appliances other

fridge/freezer

cooking

lighting

percentage of energy use

Average Energy in the residential sector (i.e. homes) is mainly used for space heating and cooling (heaters and air conditioners), and water heating.

Figures from http://www.sustainability.vic.gov.au/www/html/1820-energy-use-by-sector-.aspReference: Residential sector energy services 2004-05 - Victorian Energy Efficiency Action Statement, Department of Sustainability and Environment, 2006.

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What can we do?

• Use energy smarter in the home

• Think about what we consume/buy

• Think about what we eat

• Reduce our waste

• Walk, cycle, use public transport instead of driving (or being driven)

This is a summary of what we can do.

We will learn more about what we can do to use our energy smarter in later classes. It is not about going without, it is about being smart and efficient with our energy use.