2.2 World Energy Use

From the early 18^th century global energy use experienced an exponential growth as represented in the graph below (shown from 1850). A major contributor to this trend was the invention of the steam engine, which heralded a new era of the use of fossil fuels such as coal. Towards the end of the 20^th century the exponential nature of energy use tails off to a more linear growth, with a hint of flattening out towards the year 2000. Efforts to explain this change in trajectory based around theories of resource depletion will be included later in the chapter.

Figure 2.2.1 Global primary Energy use since 1850

(Source: The Open University Open Learn [see reference 4])
Figure 2.2.1 sourced from The Open University under a Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Licence
http://openlearn.open.ac.uk/mod/oucontent/view.php?id=399545&section=1

The figure below has been created from the US Energy Information Administration using statistics up to 2005. It shows that the world energy usage of the 3 major fossil fuels, as well as nuclear and renewable energy has increased steadily over the last 25 years.

Figure 2.2.2 Global energy consumption by fuel type since 1980. Note the figures are in watts – this is because it is showing the average energy used over that year. This is the same for the following charts

(Source EIA [see reference 5])
Figure 2.2.2 sourced from the U.S. Energy Information Administration, International Energy Outlook (2011)"
http://www.eia.doe.gov/oiaf/ieo/world.html

The figure below shows that in 2006 80.9% of the worlds primary energy comes from fossil fuels – Coal, Gas and Oil

Figure 2.2.3 Energy production worldwide in 2008

(Source Climate Lab [see reference 10])
Figure 2.2.3 sourced from Climate Lab under a Creative Commons Attribution-ShareAlike 3.0 Unported (CC BY-SA 3.0) license
http://climatelab.org/Coal_Power

Figure 2.2.4: What we use the energy for

(Source The Game Plan [see reference 1])

Figure 2.2.4 sourced from Slideshare.net (Author: Skeen) under a Creative Commons Attribution- 3.0 license
http://www.slideshare.net/skeen/game-plan-v10-1

This chart shows what we use worldwide energy for, with agriculture, Industry, transport and domestic the biggest sectors. The forestry sector figures are of interest, as not only does the cutting down of trees use a large amount of energy, but the trees lost as a result increase the effects of climate change, as they are natural carbon sinks. Climate change and its implications for the future of the biosphere will be discussed in more depth later in this chapter.

Figure 2.2.5: Energy Use by Region 2008

(Source The Game Plan [see reference 1])

Figure 2.2.5 sourced from Slideshare.net (Author: Skeen) under a Creative Commons Attribution- 3.0 license
http://www.slideshare.net/skeen/game-plan-v10-1

The difference in the levels of consumption between the poorest countries (around 80kWh per capita per year) and that of richer countries (around 8,000kWh per capita per year) reaches two orders of magnitude. Richer countries have been consuming electricity for many decades at a rate much higher than the growth rate of their populations and even of their economies. Another important fact to consider is that much of the energy consumed in Asia (especially China) is used for producing goods that are consumed in the more economically developed countries. If this was taken into account the energy demographics would be even more out of proportion.

The figures above serve to demonstrate the current world energy use. The main points to take from the graphs are:

The majority of our energy currently comes from fossil fuels. As mentioned, these fuels are incredibly energy dense, and this has enabled us to progress in terms of technology and infrastructure at a rate never before possible. The problems with becoming reliant on fossil fuels will be explained in the next section.

The energy use is not evenly distributed throughout the world. As with other issues surrounding sustainability, inequality is an important issue. More economically developed countries (MEDCs) consume the majority of the world’s energy.

As will be demonstrated, even if alternative forms of energy are taken into consideration and brought on line in a big way, there will still be a gap between the amount of energy we need and the energy that is available without fossil fuels. The challenge is to reduce our consumption of energy, which is no easy task when viewing the trends outlined in figure 2.2.1 – a steady increase of consumption over the last 150 years.

 

Activity Think about the electrical energy you use in an average day. Make a table and for each activity make a note of the power used (e.g. your laptop uses 50W – this should be written on the back of it, an energy saving light bulb uses 12W) and multiply this by the number of hours you use it for which will give you total energy for each activity. Add up the energy column to find your total electrical energy consumption for a day. Activity Power Hours Energy Laptop 50W 4 200Wh Kettle 2kW 0.5 1000Wh     TOTAL 1.2kWh Find out the conversion for kWh to tonnes of carbon and calculate your carbon footprint per year This is just electrical energy. Make a list of other forms of energy you use daily and research/estimate carbon emitted for these activities. How would this differ to somebody living in a less economically developed country? How could you reduce your consumption? For one activity (driving a car, watching TV, producing a plastic bag, turning on central heating) draw a flow diagram of where the energy comes from. An example for switching on a light is below: Switch on a light: trace the energy flow back through the national grid as electricity to the generator, round the turbine as angular momentum, back through the pipe as steam, back into the furnace as burning coal, back through the coal train to the Russian coal mine back deep down into the earth's crust and reverse a million years to a dinosaur, through the digestive system to a prehistoric plant life then right back to the beginning as a UV ray travelling from the sun. (It carries on but we'll stop there). What could you do to reduce your energy consumption? There are online carbon footprint calculators that guide you through the steps of energy use in your life:   http://www.carbonfootprint.com/calculator.aspx   http://footprint.wwf.org.uk/