2.3 Problems with Fossil Fuel Use: Resource Depletion

Fossil fuels are a form of solar energy, stored in biomass which has compacted in the earth's crust over billions of years, which is the reason they are so energy dense. There is a finite amount of fossil fuels left in the earth's sub-surface. A steady consumption of a finite resource will have a certain and inevitable conclusion: the reserves will eventually run out. An exponential consumption of a finite resource will have the same effect, only much quicker. The debate on resource depletion is not then if, but when the resource will run out.

Peak oil

Hubbert was a US geophysicist who worked for the oil industry in the USA during the 1950s. He postulated that the amount of oil being discovered was reducing, and made a prediction that oil production for the US would slow, “peak” and then drop off, following a bell shaped curve graph as follows:

Figure 2.3.1 – Hubbert's curve. The dotted red line shows when the prediction was made

(Source: Wikipedia [see reference 6])

Figure 2.3.1 sourced from Wikipedia (Author: Sfoucher) under a Creative Commons Attribution-Share Alike 2.5 Generic License
http://en.wikipedia.org/wiki/File:Hubbert_US_high.svg

Below is Hubbert’s original prediction for worldwide oil supply. He approximated world oil supplies would peak “about half a century” after the report was written (1956).

Figure 2.3.2 Worldwide peak oil predicted by Hubbert

(Source Wikipedia [see reference 7])
Figure 2.3.2 sourced from Wikipedia (Author: Hankwang) under a Creative Commons Attribution-Share Alike 2.5 Generic License
http://en.wikipedia.org/wiki/User:Kgrr/Sandbox/Peak_oil

The following is a graph with several predictions made by oil companies and other energy agencies. Some are more optimistic than others.

Figure 2.3.3 Predictions for world oil production

Figure 2.3.2 sourced from Wikipedia (Author: Hankwang) under a Creative Commons Attribution-Share Alike 2.5 Generic License
http://en.wikipedia.org/wiki/User:Kgrr/Sandbox/Peak_oil

Note that peak oil isn't the time when oil runs out; there will still be as much left in the ground as we have already extracted, but the rate of finding new wells, production and extraction will reduce.

Another important point to consider is world consumption. When consumption exceeds production there is a shortfall between supply and demand. At this point prices in oil go up, and there are concerns about where to secure oil from.

We have already established that our current energy demands are reliant on oil and other fossil fuels. Once peak oil is reached, as well as a rise in price, energy security will become an issue. As with other valuable resources, oil has the potential to cause international conflict.

Hubbert's peak has been used specifically for oil, but all production of fossil fuels and other mined minerals of which there is a finite supply follow a similar curve, leading to peak gas, peak coal, peak uranium, peak copper etc.

Some reports estimate around 40 years of petroleum supply remaining. Natural gas supply is expected to last only a little longer at around sixty years; coal is much more abundant and expected to last just over 200 years; however, it is one of the largest emitters of carbon dioxide per unit of energy generated.

As fossil fuels become harder to obtain, the energy required to mine them becomes greater. This is known as the energy return on investment (EROI): how much energy you need to put in to how much you get out. In the early days of oil discovery this was very high, as oil was easy to find and didn't require much energy to extract. Now the return is much lower, more energy is put in to get lower amounts out in a reducing spiral.

The real problem with fossil fuels is that they form an economic scenario based on highly fluctuating prices, that their availability is unequally distributed (just as much between North and South as between rich and poor) and that they have a demonstrated harmful impact on the ecosystem.

The subject of peak oil and the implications of our reliance on a substance that will one day run out has sparked heated debate in the last few years, especially as the price of oil has been steadily rising.

Now watch this TED talk covering in detail society's addiction to oil, and strategies to overcome this addiction by transitioning society to a sustainable energy system.

Rob Hopkins Transition Towns

http://www.ted.com/talks/lang/en/rob_hopkins_transition_to_a_world_without_oil.html