Living without oil

Introduction

Crude oil is currently our most important global source of energy. It is vital in the manufacture of many modern materials. But the world's supply of oil is finite, its price is unstable and our reliance on oil has damaging environmental consequences. This course explains why developing alternatives to oil is an essential and urgent task for humanity.

This OpenLearn course provides a sample of level 1 study in Science.

Learning outcomes

After studying this course, you should be able to:

• demonstrate knowledge and understanding of the core concepts, principles and language relating to the science and social issues appropriate to the development of alternatives to oil products

• demonstrate a knowledge and understanding of the impact of the use of oil on the future of our planet

• express and rewrite concepts in an objective and factually correct way

• make sense of information presented in different ways, including textual, numerical or graphical material.

1 Introducing oil

Over the last 100 years or so, humanity has come to rely increasingly on oil products. Oil is so central to modern life that it's no exaggeration to say that, at the moment, modern economies could not operate without vast supplies of crude oil.

The central contention of the Living without oil course is that developing alternatives to oil is an essential and urgent task for humanity. Those alternatives will necessarily have to involve both new sources of fuel and new technologies for transport, and new ways to produce modern materials.

So in order to set the scene, this course will address in more detail the two questions: why is oil important, and why do we need to replace it?

1.1 Oil consumption

One way of establishing the importance of oil in the modern world is simply to look at the numbers. Oil fuels an estimated 95% of the world's transport. In 2010 the world consumed a staggering 12 million tonnes of oil daily, which is roughly equivalent to 14 billion litres of oil every day. These are enormous quantities - equivalent to the volume of over 5000 Olympic swimming pools or filling enough road tankers to stretch the distance from London to New York (Figure 1).

Figure 1 A pictorial representation of the amount of crude oil consumed globally each day.

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Part of a globe of the Earth, showing the North Atlantic, with London and New York marked with red spots, and an arc of 14 oil tanker lorries stretching between them.

Figure 1 A pictorial representation of the amount of crude oil consumed globally each day.

In 2010 the UK alone was responsible for the consumption of 92.3 billion litres of oil. It can be difficult to imagine what a large quantity like 92.3 billion litres represents, so it's useful to convert this figure into something more meaningful - in this case, you will calculate the average daily consumption of oil for each person in the UK.

When performing calculations involving very large numbers, like those involved when estimating oil consumption, scientists tend to write numbers in a specific way - using scientific notation. In scientific notation, 92.3 billion litres is written as 9.23 × 10¹⁰ litres. (One billion is 1 × 10⁹, so 92.3 billion becomes 92.3 × 10⁹, which is written in formal scientific notation as 9.23 × 10¹⁰.)

A typical adult needs to ingest up to 3 litres of water in drinks and food each day - so it could be argued that a typical UK adult is responsible for the consumption of more oil than drinking water!

In assessing the importance of oil and its potential replacements, it's inevitable that some numerical comparisons have to be made. This book will include a small number of calculations - in particular, it will be important at times to be able to convert quantities quoted in one set of units into another.

The oil industry tends to measure the quantity of oil in barrels - a rather old-fashioned unit, given the fact that oil is no longer transported in barrels. A careful web search for the world consumption of oil might lead to the annually published BP Statistical Review of World Energy (the source of most of the data in this section), where the value quoted will always be in millions or billions of barrels of oil. The daily global consumption of oil for 2010 is given in the BP Statistical Review as 87 million barrels of oil per day. The price of crude oil is generally given as the price (in US dollars) per barrel. On the other hand, scientists internationally tend to use SI units, where SI is an abbreviation for the Système International d'Unités (International System of Units). Examples of SI units are the kilogram or tonne for mass and the litre for volume. This course uses SI units wherever possible, but on occasions it will be necessary (or just more convenient) to go along with the oil industry and quote values in barrels.

In order to translate the units used in oil industry publications to those more commonly used in scientific publications, you need to be able to convert 'barrels' into standard SI units of mass and volume.

Converting quantities of oil quoted in barrels to litres is relatively straightforward, since one barrel of oil contains a volume of 159 litres. To convert from barrels to tonnes is slightly trickier as it depends on where the oil comes from. Crude oils from different sources have different densities but, on average, one barrel is equivalent to 0.14 tonnes of oil.

Crude oil in its unrefined state is not very useful - it has to be processed to produce the fuels and materials so essential in the modern world. However, for now, you just need to be aware that each barrel of oil undergoes extensive refining and processing to produce fuels and materials. You estimated that each person in the UK consumes around 4 litres of crude oil each day - in the following sections you will explore what that 4 litres is used for.

Activity 1 Living without oil

The estimated time for this activity is 15 minutes.

Watch the 3-minute video clip in which some of the central issues surrounding living without oil are introduced and then answer the questions below. If you have time, you may wish to watch the whole clip through once, and then read the questions before watching the video again. Use the pause button while noting down your answers to each question.

Download this video clip.Video player: Video 1

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Transcript: Video 1

Voice over

There is now virtually no prospect of holding temperatures to 2 degrees if the science is correct. We're now talking about catastrophic climate change.

Biofuel scientist

What we have here is algae. Algae communicate by releasing chemicals, and the golden chalice is if we can find the chemical that they're producing that says to the other algae let's make more oil.

John Craven

But how close are you to this becoming anything like a commercial reality?

Presenter

What you're seeing in there is used cooking oil we've pumped over to the reactor and you end up with the biodiesel itself.

News reporter

Hydrogen could provide the ultimate renewable and clean fuel.

The consensus is among many in the motor industry that hydrogen really is the way ahead, the cure for so many of the motor industry's fuel problems, but there are major obstacles in the way. Of course there needs to be huge investment in the infrastructure, and we also need to be persuaded that hydrogen cars can be successful.

News reporter

You used to only see electric cars at motor shows as designers showed off their visions of the future. Now, though, manufacturers are racing each other to get electric cars onto the roads.

Quentin Willson

All these technologies need to be tested so we see which is the best. They may run parallel but what we've got to do is start looking at an alternative to the shackles of oil.

Voice over

There are very few things that can't be made in other products. The reason why it hasn't happened as fast as it ought to happen from environment perspectives is not that it can't happen, it's that the alternative's been too cheap.

End transcript: Video 1

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Video 1

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Question

• a.The clip states that 'the extraction and use of oil have damaging impacts on local environments and global climate'. Give one example each of
  • i.how the extraction of oil has damaged a local environment
  • ii.how the use of oil damages local environments
  • iii.how the use of oil has a damaging impact on the global environment.
• b.What alternatives to oil as a source of transport energy feature in the video?
• c.There are three broad alternatives to oil-based transport: biologically derived liquid fuels (biofuels), hydrogen and battery electric vehicles. The video makes it clear that all these technologies are likely to be tested in the near future. Which of these, if any, do you personally think is most likely to feature in meeting our transport needs in the long term?

Answer

• a. 

  • i.The extraction of oil can damage local environments through oil spillages; one example would be the Deepwater Horizon oil spill (Section 6.2), though there are many others.
  • ii.The use of oil can damage local environments through air pollution; one example you might mention is the role that particulates from diesel engines play in smog formation, though again you may have chosen other examples (Section 8).
  • iii.The most damaging impact that the use of oil has on the global environment is its contribution to anthropogenic global warming (Section 7).
• b.The alternatives to oil (which all feature in the video) are:
  • getting oil (biofuels) from algae
  • converting used cooking oil to biodiesel
  • using hydrogen-fuelled cars
  • battery electric vehicles
• c.Your answer will depend on your point of view, and your view may change. For my part (John Baxter), my experience in writing the course has led me to feel that perhaps battery electric vehicles may dominate the long-term future of transport - but I am far from sure!

2 Oil for personal transport

Figure 2 Personal transport relies on crude oil.

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Part of one carriageway of a motorway showing a traffic jam of cars and lorries.

Figure 2 Personal transport relies on crude oil.

Most obviously, oil products provide us with the energy to move us around (Figure 2) and a proportion of the 4 litres of crude oil each person consumes each day will be used to fuel personal transport. Several crude oil products are used to fuel transport. Petrol (called gasoline in some parts of the world) and diesel are the fuels primarily used for road transport, whilst kerosene is used to fuel jet aircraft.

You can start to estimate how much of the 4 litres each person consumes is used for personal road-based transport by roughly estimating how much fuel you use for personal transport each day. You could begin by trying to select a typical day and estimating how much fuel was consumed on that day; but transport needs vary so much from day to day, that it is more appropriate to look at a longer period, and take an average. One way to do this would be to look at the transport fuel consumed over a period of a week: Table 1 shows estimates of the amount of fuel (petrol) used for car transport in a relatively quiet week for the author.

In general, UK petrol engine cars have an average fuel consumption in the region of 17 kilometres per litre (km l⁻¹), which is the figure that has been used in the calculations in Table 1. Diesel engines tend to be more efficient and deliver an average of around 23 km l⁻¹.

Here scientific SI units, km l⁻¹, are used rather than miles per gallon which might be commonly used in the UK. Expressing kilometres per litre in the form km l⁻¹ is again a standard scientific way of expressing things.

Here is an example of the type of calculation used to generate the final column in Table 1.

Approximate distance to cinema and back = 30 km

Estimated fuel efficiency = 17 km l⁻¹

Table 1 and the answer to Question 2 imply that the author's car is responsible for the consumption of 4.1 litres of crude oil a day. Three people live in the author's household and share the use of the car, so arguably the car's consumption can be divided between three, so the car alone accounts for about 1.4 litres of the 4 litres of crude oil each person in the author's one car household might be expected to consume each day. Coincidentally the author's calculations imply that in his household his car consumes the same amount of crude oil each day (4.1 litres) as the average UK citizen. Your calculations may give a quite different figure, depending on the car and the distance travelled.

The week shown in Table 1 is not a typical one for the author's family as the annual mileage recorded for his car is in the region of 10 000 miles or approximately 16 000 kilometres. This suggests that the car is responsible for not 1.4 but around 1.9 litres of the 4 litres of crude oil each of the three people in the household might be expected to consume each day. (You may like to check this calculation for yourself.) These are very approximate calculations, but they demonstrate that personal road transport is responsible for a very significant proportion of the crude oil consumed in the developed world. The calculation did not take into account trips made by public transport which also will be responsible for a small proportion of our daily consumption of crude oil.

Other forms of transport are important too - aviation is a huge consumer of fuel derived from crude oil (largely kerosene). A single return flight to New York from London could easily triple an individual's annual personal consumption of crude oil products.

However, as important as personal transport is in determining the amount of crude oil we consume, to gain a full appreciation of the centrality of oil in the modern world you also need to look at the role crude oil plays in transporting goods.

3 Virtual oil

There may be those amongst you who have used no powered transport at all in the last week - perhaps you cycled, walked or ran everywhere you needed to go, or even rode a horse. However, in the developed world, even individuals who don't personally use powered transport live lives that rely heavily on oil. Almost everything we buy has been produced by a process that consumes oil - it all contains what might be called 'virtual oil'.

Think firstly about the food we eat. Diets in the developed world rely on the cheap transport we get from oil. This applies whether we are eating intensively reared meat flown from the other side of the world or 'organically' grown vegetables driven from 30 kilometres away. Clearly there can be vast differences in the amount of oil consumed in bringing different foodstuffs to us, depending both on the distance travelled and the type of transport used.

In the past, campaigners in the UK have used the concept of 'food miles' to try to capture the differences in the quantities of oil consumed to get different goods to us - their focus was on making consumers aware of the greenhouse gas emissions involved (see Section 7 for more on this). The 'food miles' associated with an item of food measures the distance from the point at which the food was produced to the point at which it is consumed, but the concept has since come under criticism as too simplistic.

Whilst the greenhouse gas emissions resulting from transport are an important part of the environmental impact of the things we buy, it's important to take into account the emissions involved in every stage of an object's production and use. In more recent years, campaigners have tended to use the concept of a 'carbon footprint' - an estimate of the total impact a product has on anthropogenic global warming. It is an area where there are often no clear-cut answers, and differing estimates of environmental impact can often lead to controversy.

The use of oil-based transport makes an almost invisible contribution to the manufacture of all modern goods. I own a cotton jacket (Figure 3) whose label tells me that it was manufactured in Romania. It is immediately apparent that oil will have been used to transport the jacket from Romania to the shop in Manchester where I purchased it (there were probably a few stops along the way). Cotton is not a crop that is grown commercially in Romania, so the cotton will have been imported into Romania from another country - perhaps Egypt or China. This too will have involved the consumption of oil.

Figure 3 (a) The author in his cotton jacket. (b) A close up of the jacket's label showing the composition and source of the materials from which it was made.

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(a) A gentleman wearing a white shirt, dark trousers and a sand coloured jacket.(b) A fabric label from the jacket, with the following wording - Made in Romania. Then the size, together with various manufacturers numbers and symbols to indicate how the jacket should be laundered. The composition is given as 100% cotton, body lining 65% viscose, 35% polyester, sleeve lining 100% polyester.

Figure 3 (a) The author in his cotton jacket. (b) A close up of the jacket's label showing the composition and source of the materials ...

The deceptively simple jacket is an amalgam of different parts manufactured all over the world. It has a lining made from polyester and viscose - two different synthetic materials which are likely to have been manufactured at different sites. It has plastic buttons and is held together by cotton threads. The cloth has been dyed an attractive olive colour - the dye will have been manufactured at one site and transported some distance to the factory that dyed the cloth.

The manufacture of the jacket is only possible because cheap transport fuelled by oil allows the manufacturer to assemble all the parts needed. This relatively complex process of bringing together parts from all over the world applies to almost all the goods around us in our homes. You have explored the manufacture of a jacket - but think of how many more parts and materials have to be produced separately and brought together to manufacture a complex object like a television or computer.

It is very difficult to state accurately how much of an individual's daily crude oil consumption is taken up by the 'virtual oil' in the goods they use. However, you can make a rough estimate. According to International Energy Authority statistics, approximately 61% of crude oil consumed is used for transport (this includes both personal transport and the transport of goods), and you have estimated that on average each individual in the UK is responsible for the consumption of 4 litres of crude oil.

This estimate of a daily consumption of 2.4 litres of crude oil for transport includes both the personal and public transport discussed in Section 2 and the 'virtual' crude oil in the goods and food used by each individual.

Most crude oil is ultimately used as fuel - so while in the UK a person might on average use 2.4 litres of their 4 litre allocation for transport in all its forms, a further 1.1 litres are used as fuel to provide energy for activities other than transport - this includes domestic heating fuel, and fuels for industrial and agricultural processes.

4 Oil as a source of modern materials

Figure 4 A UK citizen's 4 litre use of crude oil in graphical form.

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A bar chart with the vertical axis labelled individual use of crude oil/litres and with values from zero to 2.0 litres marked in intervals of 0.5 litres. There are 5 bars. Working from left to right, the labels and heights of the bars are as follows: personal transport 2.0 litres; 'virtual' oil about 0.4 litres; heating/industrial, etc. 1.1 litres; lubricants, waxes, etc. 0.3 litres; petrochemicals 0.2 litres.

Figure 4 A UK citizen's 4 litre use of crude oil in graphical form.

So far, 3.5 litres of the UK citizen's 4 litre daily allocation of crude oil have been accounted for. The bulk of the remaining 0.5 litres is used as lubricants, waxes and road coverings, but a small proportion of the allocation - in the region of 0.1−0.2 litres - is converted to petrochemicals (Figure 4). As the name implies, these are chemicals derived from crude oil (petroleum), although the term is also used to refer to products derived from natural gas. Petrochemicals are used to manufacture a huge variety of materials - including plastics, pesticides, drugs, adhesives, paints, and so on.

The proportion of crude oil used to make petrochemicals is small but it is a very important part of the story. The economic importance of petrochemicals can be seen from the fact that recently the world production of transport fuels from crude oil was estimated to have a value of US $385 billion, whilst world production of petrochemicals was estimated to have a value of US $375 billion. Over 80% of crude oil is used to make transport fuel, while 3-5% is used for petrochemicals, yet their value is roughly the same.

Examining the statistics is one way to gain an insight into the importance of petrochemicals, but another way is to look at the things around you in your home. Let's return momentarily to my jacket: the lining is made of the synthetic materials polyester and viscose (Figure 3b) - products that are both to a greater or lesser extent derived from crude oil. More precisely, these materials are made from petrochemicals.

Polyester is ultimately derived from a petrochemical called xylene. Viscose is derived from cellulose extracted from plants, in a manufacturing process that incorporates a number of petrochemicals. The plastic buttons, and the dye too, are almost certainly derived from petrochemicals.

Figure 5 A selection of products made from petrochemicals.

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A photograph of various items including clothes, candles, adhesive tape, face and hand creams, chewing gum, washing line, string, tin of paint, aerosol can of insect repellent, baby oil, disinfectant, washing powder, fabric dye, mothballs, a can of butane, a petrol can and a pair of trainers.

Figure 5 A selection of products made from petrochemicals.

It's hard to exaggerate how commonplace petrochemical products have become in our daily lives - we are surrounded by them (Figure 5). We walk on petrochemical products in the form of synthetic fibre carpets and vinyl floorings. The colours on the walls which surround us are derived from petrochemicals. We sit on seats stuffed with plastic foams derived from petrochemicals. Crude oil is the source of almost all the many plastics we use. For example, we get clean water from plastic pipes, whilst other plastic pipes take our waste water away. Our music players, computers and mobile phones are all made in part from plastics derived from oil. The food we eat doesn't just rely on oil for the transport elements of its production; it also relies on the pesticides, herbicides and fertilisers which are usually chemically derived from oil. The packaging which keeps our food fresh or allows us to transfer it directly from the fridge to the oven is derived from oil. Modern medicines are almost always derived from oil, as are replacement heart valves and artificial limbs.

The list of modern goods that rely on the products of the petrochemical industry is almost endless - that is why the small fraction of a barrel of oil used for petrochemicals is so valuable.

5 Is the oil running out?

Oil is one of a number of fossil fuels - fuels derived from the fossilised remains of living things. The two other most abundant fossil fuels are natural gas and coal.

The supplies of all fossil fuels are finite and (in theory) if we keep using them, they will eventually run out. The imminent exhaustion of oil supplies has been predicted a number of times in the last 100 years. In 1919 the head of the prestigious US Geological Survey predicted that the United States would run out of oil within nine years. Almost 100 years later, oil is still being extracted in the US. Discoveries of new oilfields and more efficient extraction techniques have so far kept the oil flowing, though the quantity of oil produced has declined.

There is no question that at some point the oil will run out, but this is unlikely to happen in our lifetimes or even our children's lifetimes. However, when the oil wells run dry is not the key question - or at least not the one likely to affect our or the next generation. Instead, the key question is whether we can produce enough oil to satisfy global demand. Consider Figure 6, produced in 2003 by members of the campaigning organisation the Association for the Study of Peak Oil. The figure shows an estimate of the global production of oil over a 120-year period.

Figure 6 An estimate of past and future oil production which was produced by the Association for the Study of Peak Oil in 2003.

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A graph with the vertical axis labelled annual crude oil production/billion barrels and running from 0 to 35, in intervals of 5. The horizontal axis runs from1930 to 2050, in intervals of 10 years. The curve runs gently upwards from a value of about 1 billion barrels in 1930 to 3 billion barrels in 1950, then rises more steeply to about 20 million barrels in 1970. After a peak around 1979 at 22 million barrels, the curve falls back to 20 million barrels in 1981 and then resumes its upward trend to reach a rounded peak at about 30 billion barrels around 2010. After that, the curve falls steadily to about 13 billion barrels in 2050.

Figure 6 An estimate of past and future oil production which was produced by the Association for the Study of Peak Oil in 2003.

Figure 7 Estimated annual energy demands derived from the International Energy Authority (IEA). Mtoe, million tonnes of oil equivalent, is a unit of energy equivalent to the energy released on burning one million tonnes of crude oil.

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A graph showing the consumption of various energy resources with respect to time. The vertical axis is in Mtoe (millions of tonnes of oil equivalents) from 0 to 7000 in intervals of 1000. The horizontal axis is labelled over 60 years from 1970 to 2030 in decade intervals. The first curve on the graph represents the increase in oil usage over the 60 year period as it rises from 2500 Mtoe to 5750 Mtoe. The next two curves represent natural gas and coal. These rise less steeply over the 60 year period. Natural gas rises from about 1000 Mtoe to 4000 Mtoe and coal from 1400 Mtoe to 3500 Mtoe. The next curve is energy from other renewable resources which rises slowly from 750 Mtoe to 1800 Mtoe over 60 years. The two final curves show the rise in nuclear and hydro power. These two curves show little increase over the 60 years both starting from about 10 Mtoe increasing to 800 Mtoe for nuclear power and 400 Mtoe fro hydro power. In general the graph predicts that oil and other fossil fuels will still be the major sources for world energy consumption towards the year 2030, with oil being consumed the most.

Figure 7 Estimated annual energy demands derived from the International Energy Authority (IEA). Mtoe, million tonnes of oil equivalent, ...

The idea that we are already at, or about to hit, 'peak oil' is a highly disputed one - and heated arguments have taken place about the validity of the ideas behind Figure 6. The debate can take at least two forms. Put crudely, the first form of the debate is between the geologists and the economists. Geologists point to the declining rate of discovery of new oilfields and the inevitable decline in resources. Economists claim that shortages of oil will raise prices - spurring technological development and the exploitation of sources of oil previously considered uneconomic. A second form of the debate occurs between different geologists - over exactly when the peak in oil production is likely to occur.

6 Future sources of oil

The debate as to when, or if, 'peak oil' will occur, centres in part on the extent to which it will be possible to exploit new sources of oil. There are many in the oil industry who argue that the new, so-called 'non-conventional' sources of oil will become far more important in the future.

These new sources of oil are all more expensive than conventional oil, and their exploitation will pose questions about what environmental consequences we are prepared to accept in order to satisfy our oil habit. You will look at each of these non-conventional sources of oil in turn, in order to assess their potential to fill the gap between demand and supply of oil, and to assess their possible environmental impacts. Firstly, you need to know how 'conventional' oil is extracted.

6.1 Conventional oil

Conventional oil is a loosely defined term covering any crude oil that can be extracted from the ground in the 'conventional' way; that is, it is extracted using standard oil well technology.

Conventional oil is generally found in underground rocks known as reservoirs, where it can sometimes be associated with natural gas. The oil is generally under great pressure and initially when an oil well is drilled, the oil will spontaneously flow to the surface. Indeed the problem at this stage is how to control the flow and avoid a 'blowout', an occurrence that plagued the early oil wells and cost many lives (Figure 8).

Figure 8 The blowout (uncontrolled release of oil and gas under great pressure) of an oil well in Texas in 1901.

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A black and white picture of a drilling rig with a plume of black oil shooting vertically upwards out of the picture, with some of it beginning to fall back down.

Figure 8 The blowout (uncontrolled release of oil and gas under great pressure) of an oil well in Texas in 1901.

Modern oil wells are designed to avoid disastrous blowouts and have sophisticated pressure release systems which allow the controlled release of oil at the surface. However, blowouts still occur occasionally, as you will see in Section 6.2.

The stage at which oil flows spontaneously to the surface is known as the primary recovery phase (Figure 9a) and only a small proportion of the oil in the reservoir can be extracted in this way. Eventually, the pressure in the oil reservoir will drop, and to prolong extraction it becomes necessary to maintain the pressure underground by injecting pressurised water or gas, or both, into the reservoir (Figure 9b). This phase of production is known as the secondary recovery phase.

In order to improve recovery still further, chemical or biological agents may be added to the injected water, or steam may be pumped into the reservoir, in order to reduce the viscosity (thickness) of the crude oil. The term 'viscosity' may be new to you; in scientific terms, viscosity is a measure of how easily a liquid flows - a liquid with low viscosity such as water flows easily, whilst a liquid with high viscosity (e.g. treacle or honey) does not flow easily.

Maximise

Figure 9 The primary and secondary recovery phases of conventional oil extraction. (a) Primary recovery: the oil flows to the surface under its own pressure. (b) Secondary recovery: in this example, water is pumped into the well to force the oil out.

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These are two similar sketches of vertical sections through the Earth's surface. They show a gentle upwards fold of three rock strata below the surface. There are narrow bands of impermeable rock top and bottom and a central larger section of permeable rock. The permeable rock has oil filling the upper part, floating on water below, with a horizontal line separating them. In (a), there is an drilling rig with a pipe down into the oil layer and arrows showing that the oil flows under its own pressure into the pipe and upwards to the surface. In (b), in addition to the oil production well seen in (a), there is also a water tank at the surface with a pipe down into the water layer, labelled water injection well. There are arrows to show that the water is pumped down the pipe and out into the water layer below the oil. This results in the water level below the oil being higher in (b) than in (a). Oil is then forced up into the pipe of the oil production well and up to the surface in the same way as in (a).

Figure 9 The primary and secondary recovery phases of conventional oil extraction. (a) Primary recovery: the oil flows to the surface ...

Under ideal conditions, secondary recovery methods can result in up to 70% of the initial oil present in the reservoir being recovered, but the processes are expensive and for many smaller fields the amount of extra oil recovered may not be worth the investment.

6.2 Non-conventional oil

It is generally agreed that there are huge quantities of non-conventional oil still to be extracted, and the quantities are estimated to be greater in total than those of the unextracted conventional oil remaining. However, by definition the non-conventional oil is much harder to get out of the ground and to process. The two types of non-conventional oil most often discussed are oil sands and heavy oils, and you will briefly explore issues related to these. You will also look at three other types of oil that might be classed as non-conventional: deep-water oil, polar oil and natural gas liquids.

Oil sands

Figure 10 An aerial view of oil-sand mining at Fort McMurray, Alberta, Canada showing the huge scale of the extraction process.

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An aerial photograph of a piece of land, with what appear to be brownish tracks criss-crossing it, and paler brown areas between. At the top of the picture, the land appears white as if covered by snow.

Figure 10 An aerial view of oil-sand mining at Fort McMurray, Alberta, Canada showing the huge scale of the extraction process.

Oil sands (also known as tar sands) are formed when oil flows into near-surface sands from deeper underground reservoirs. Exposure of crude oil to air and bacteria close to the surface degrades the oil into thick, viscous bitumen, with the consistency of very thick treacle. The fact that the bitumen is mixed with sands, clays and water - together with its extreme viscosity - makes it difficult and expensive to extract the oil. Until very recently, oil sands have been collected by large-scale strip mining (Figure 10), which involves scooping up vast quantities of the sands using huge machines. The enormous volumes of oil sands are then heated to around 80 °C to separate and chemically change the bitumen to produce a material that flows more easily and has a chemical make-up more similar to that of conventional crude oil. This is a complex, energy-intensive and expensive process, but in recent years, as the price of oil has increased, it has become an increasingly competitive alternative to conventional oil sources.

Where oil sands lie too far beneath the surface to allow surface mining, huge volumes of steam or hot carbon dioxide gas are injected deep below ground; after several months, the viscosity of the oil is lowered enough to allow the oil to be pumped to the surface.

The world's largest producer of crude from oil sands is Canada, where the Athabasca area of northern Alberta has reserves of oil second only to those of Saudi Arabia. It takes two tonnes of oil sands to produce one barrel of oil.

• What percentage by mass of oil sand is recovered as crude oil, and what does this tell you about the amount of waste generated by this process?

• One barrel of oil has a mass of approximately 0.14 tonnes, so two tonnes of oil sand might produce approximately 0.14 tonnes oil.

  So percentage of oil recovered = (0.14 tonnes/2 tonnes) × 100% = 7%

  This implies that a staggering 93% of the oil sand is discarded as waste.

The oil from oil sands has been described as the dirtiest oil on Earth. The huge-scale strip mining destroys habitats (Figure 10). The processing creates huge quantities of toxic residues. It takes three to five times more energy to extract crude oil from oil sands than it takes to extract conventional oil. According to one estimate, this means that burning a litre of petrol from oil sands results in 20% more greenhouse gas emissions than burning a litre from conventional sources.

Polar oil

The Arctic is seen by many as an unspoiled wilderness that should be protected - iconic images of polar bears trapped on melting ice floes have often been used to dramatise the effects of anthropogenic global warming. But many of the states bordering on the Arctic view the region in quite a different way - they see it as a potential source of valuable oil and minerals. The Arctic is estimated to hold 13% of the world's resources of oil (and 30% of its gas). The US Geological Survey has suggested that it is the largest unexploited source of conventional oil in the world.

Figure 11 The vast Prirazlomnaya platform, an ice-resistant stationary drilling and oil production platform for use in the Arctic Barents Sea.

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A photograph at sea with an ocean-going tug in the foreground, completely dwarfed by a huge floating 'factory' with a drilling rig, a huge chimney, several cranes and a helicopter landing deck.

Figure 11 The vast Prirazlomnaya platform, an ice-resistant stationary drilling and oil production platform for use in the Arctic Barents...

Drilling for oil in the Arctic poses a number of problems: the extremely low temperatures, the perpetual night in winter, shifting pack ice, icebergs and storms. So far, oil companies have concentrated their efforts around the more accessible fringes of the Arctic. The next phase of oil recovery is likely to focus on sheltered shallow-water regions close to shore. However, plans are well under way to start exploring for oil in the less accessible parts of the area. In order to drill in deeper water, vast steel platforms are being built, such as the Russian Prirazlomnaya platform (Figure 11). The huge bulk of such platforms will stop them from being crushed by the shifting pack ice that covers the sea for eight months of the year. However, these platforms will not be suitable for drilling in really deep Arctic water where it's likely that ice-resistant ships will float on the surface collecting oil from underwater wells below.

Plans to rapidly develop Arctic oil resources have enraged environmental activists, who question the safety of deep-water drilling - especially in the light of the Deepwater Horizon incident. Others argue that the real risk will not be from the wells themselves but from the oil tankers which will have to make their way through the icebergs and pack ice. Oil companies are researching the best ways to avoid oil spills and to mop them up if they do happen. But the environmentalists are not convinced, and many have called for a moratorium on all Arctic oil exploration. This can set them against the local population who see the oil industry as a vital potential source of income.

7 Oil and anthropogenic global warming

Since the mid-19th century, human industrial and agricultural activity has caused a change in the concentrations of gases in the Earth's atmosphere. In particular, there has been a dramatic increase in the concentration of atmospheric carbon dioxide (Box 1), caused primarily by the combustion of fossil fuels.

Figure 12 shows the emissions of carbon dioxide resulting from combustion of fossil fuels (and cement production) over the last 200 years.

Figure 12 Anthropogenic emissions of carbon dioxide over the last 200 years to 2008. Note that a small but significant contribution to carbon dioxide emissions comes from the production of cement rather than the combustion of fossil fuels. Another small but significant contribution to carbon dioxide emissions comes from the burning of excess gas produced by oil rigs and refineries - gas flaring.

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A graph with the horizontal axis marked in years from 1810 to 2010, in intervals of 10 years. The vertical axis is labelled annual CO₂ emissions/billion tonnes of carbon and runs from 0 to 9 in intervals of 1. There are 6 lines on the graph, labelled gas flaring, cement production, natural gas, oil, coal and total. The gas flaring line runs almost along the horizontal axis for the whole of its length, with a very slight rise in the 1970s to less than 0.1 billion tonnes of carbon emitted, then a fall again, and a continuing very slight rise after 2000. The cement production line also runs along the horizontal axis for most of its length, then starts to creep upwards very slightly from about 1950 onwards and rises very gently to about 0.3 billion tonnes of carbon emitted in 2008. The natural gas line runs along the horizontal axis till about 1940 and then rises, very slowly at first, then slightly faster to reach its highest level at about 1.5 billion tonnes of carbon emitted in 2008. The line for oil leaves the horizontal axis in about 1910 and rises slowly at first, then much faster from 1940 onwards to reach a peak in about 1980 of 2.5 billion tonnes of carbon emitted. There is then a slight fall and the rise resumes to reach just over 3 billion tonnes in 2008. From about 1840 onwards, the line for coal rises slightly irregularly, but generally steadily upwards to about 2000 when about 2.3 billion tonnes of carbon are emitted, then there is a very steep rise over the next 8 years to about 3.7 billion tonnes. The final line, labelled total, is the sum of all the other lines. From about 1840 onwards, since only the emissions for coal are significant, it rises with the coal line, but then gradually rises above it, as the other sources add in. By 1950, the total is about 1.8 billion tonnes and then the line rises very steeply, though in a slightly jagged way, to nearly 9 billion tonnes in 2008.

Figure 12 Anthropogenic emissions of carbon dioxide over the last 200 years to 2008. Note that a small but significant contribution to ...

At present the combustion of coal and oil are responsible for broadly similar levels of CO₂ emissions, whilst emissions from the combustion of natural gas are approximately half those of either coal or oil.

In order to more fully describe the combustion of coal, natural gas and oil, it is necessary to use chemical equations, as described in Box 2. If you have studied chemistry recently, the concepts may be relatively familiar and you may be able to read through this box quickly, or skip it completely.

The fossil fuels burned in the 200 years since the Industrial Revolution were formed underground over many millions of years. The sudden return of ancient carbon to the atmosphere upsets the outer Earth's energy balance, and is responsible for anthropogenic global warming. This is an issue of much concern among scientists, environmentalists and politicians.

The science behind global warming will not be discussed in any detail in this course; but the following text will discuss briefly why gases like carbon dioxide affect the global temperatures. A number of gases like CO₂ absorb some of the Sun's energy which might otherwise be reflected back into space, resulting in an overall warming of the atmosphere. Gases that can act in this way are called greenhouses gases. The two major greenhouse gases are water vapour (H₂O) and carbon dioxide (CO₂), although methane (CH₄) is also an important greenhouse gas. Without the warming effect of these naturally occurring gases, the temperature at the Earth's surface would be closer to −20 °C than the current mean value of 15 °C. Increases in carbon dioxide and other greenhouse gas concentrations will inevitably lead to increases in global mean surface temperatures.

The increasing concentration of CO₂ in the atmosphere has already resulted in small but measurable increases in global temperatures. In fact, the 20th century saw an increase in the annual mean surface temperature of about 0.7 °C. Predicting future global warming is beset with uncertainties, but our best estimates are that if there is no change in the current 'blend' of energy sources (known as the 'business-as-usual' scenario), the global mean surface temperature will rise by between 1.1 °C and 6.4 °C over the next 100 years or so.

Increased surface temperatures are likely to have a variety of effects. One major effect would be on sea levels: increases in global temperature are likely to be accompanied by a rise in global sea level, because of thermal expansion of the oceans and melting of land-based ice. A 'business-as-usual' scenario suggests a sea-level rise of between 0.2 m and 0.65 m by the end of the 21st century. Low-lying island states are particularly threatened by rising sea levels; but other effects could include greater incidence of storm-surge flooding, higher coastal erosion, and loss of property and coastal habitats. Rising sea levels could have devastating social and economic consequences.

Other effects of anthropogenic global warming include changes to the timings of the seasons, with effects on agriculture, changing distribution of diseases and damage to ecosystems.

To stabilise carbon dioxide levels would require an immediate reduction of emissions from human activities. Yet even if fossil fuel burning stopped immediately, the temperature rise would continue because of the time lags in atmospheric systems.

The combustion of oil is a major contributor to carbon dioxide emissions - contributing just over one-third of all anthropogenic emissions (Figure 12), a proportion similar to the emissions produced from coal, which is primarily burnt to generate electricity.

Clearly if we are to reduce emissions of carbon dioxide, reducing our reliance on oil will not by itself be enough - we definitely need to do something to replace our coal-fired power stations. Nonetheless, developing sustainable, efficient alternatives to oil-based fuels could make a major contribution to efforts to reduce greenhouse gas emissions.

8 Other pollution from conventional road transport

Recent concerns in this area have tended to focus on the problem of carbon dioxide emissions, but our current modes of road transport are also responsible for the emission of various other pollutants. You will briefly explore these here, as any alternative to oil-based road transport should address the need to minimise these pollutants as well as reduce carbon dioxide emissions.

9 Conclusion

Many environmentalists argue that we should be attempting to change individuals' behaviour rather than increase the efficiency of transport technologies. This implies a dramatic reduction in the use of the most energy-intensive modes of transport - car and air travel. But many individuals and politicians baulk at the prospect of 'turning the clock back' to a level of mobility considerably less than that we currently enjoy. Car use is now deeply entrenched in our society and economy, however environmentally problematic that may be.

There are clearly two extreme views here. One might be that we can solve the issue of anthropogenic global warming if we get the technology right. The other extreme would be to argue that only by changing our transport habits can we hope to begin to reduce emissions. You will have to decide where you stand on this issue. Perhaps, like the author, you will feel that the truth lies somewhere between these two extremes.

Activity 2 The peak oil debate

The estimated time for this activity is 40 minutes.

While studying this course you have explored some important trends in oil production and consumption in the United States, China and the Middle East. For many commentators, these trends are not as important as the bigger question: is overall global oil production about to decline? Many argue that we are at, or very close to, the point when the world's production of oil will peak and start to fall (Section 5). This idea, known as the 'Peak Oil hypothesis', is a controversial one and in this activity you will explore the views of two commentators from opposite sides of the debate.

You will listen to short extracts from interviews with the two. You should bear in mind that these are extracts rather than the full interviews.

If you have time, you may wish to listen to the whole of each extract through once, and then read the questions before listening to the extract again. Use the pause button while noting down your answers to each question.

Part I

The first commentator is Dieter Helm, Professor of Energy Policy at the University of Oxford, who specialises in issues related to energy and the environment. He doubts the validity of what he calls 'Peak Oil' hypotheses.

Listen to the 5-minute extract of the interview and then answer the following questions.

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Transcript: Audio 1

Dieter Helm

My name is Dieter Helm. I am Professor of Energy Policy at the University of Oxford, and I'm also a Fellow in Economics at New College.

Peak oil's become one of those slogans covering a multitude of sins, and there are a variety of different hypotheses competing for space around this term. First of all there are people who believe that the Earth's resources are in some physical sense limited. Then there are those people who think that whether they're limited or not, the resources that we need now, particularly oil, and to a lesser extent gas, are controlled by a small number of countries who can exert political pressure and will indeed throttle the consuming countries. Then there are people who believe that it's inevitable that the demand for these fuels will carry on going up, so whatever the supply, demand will outstrip supply and therefore the price will go up, and these are the price peak oilers.

If we unpack the various components of peak oil claims, the starting point is that there's somehow some sort of physical limitation. Now in some pure theoretical sense it's got to be roughly right that there is some physical limit, but that's not really an interesting question from an energy perspective, unless that physical limit is somehow imminent, and about to bear down upon us, and mean that supply can't keep up with demand.

Now a moments reflection of the nature of the Earth's crust will tell you that it's absolutely riddled with carbon. Past photosynthesis in geological history has taken a great deal of carbon out of the atmosphere and deposited it in our rock structures. A little bit of it has percolated up from those deposits laid down in estuaries and ancient seas, and so on, has percolated up to find holes, gaps in the rocks, and that's what we call oil and natural gas, in a conventional sense. And so far all our technologies have enabled us to do is drill holes into those reservoirs and take out, in the case of oil, less than 50% before we have abandoned deposits; that's all we've achieved

The unconventional resources, the stuff that's riddled throughout those rocks which haven't found those nice, neat reservoir deposits, we've hardly scratched the surface of that. So it's not right to say, from a physical point of view, within any reasonable and relevant time period, that we have limited resources. What we have is limited technologies to get those resources, and then the question is are we on the brink of, and will we in the future, get the technology to access more of those resources? And the answer to that question is yes, and particularly if the price is high enough. So as the price of oil goes up people explore all sorts of other alternatives and they push the technological boundaries.

So, first of all, can we get more out existing wells? Yes, that's about pressure, and one of the ironies of climate change is that if we were to use sequestrated carbon, and inject it into some of those holes, we might get even more carbon fuels out as a result. So, there's an enormous amount that we could get out of existing resources, which just isn't economic at the moment.

But then there are the shales. And the shale gas revolution, shale oil following on, has been one of the great events in the last several decades in the fossil fuel industries. This is big stuff, and it's big stuff not because of some scientific change, not because the resources have changed, they're physically just what they were, but simply because higher oil prices have pushed through these new technologies.

If for a moment you were to suspend belief in peak oil, and take seriously the claim that the Earth's crust is riddled with fossil fuels, and that technological breakthroughs are making those fossil fuels more and more accessible. You would then have to entertain the possibility that the price of oil and gas is not going to go north, but could possibly go south. In other words, contrary to many of the wilder claims, we're not on the verge of a doubling of the oil price. Alright it might happen temporarily if we have an explosion in Iran or whatever, but a fundamental shift upwards in the oil price, and the gas price. We may be in a world in which they're going to be low, and even possibly very low. Now, from a climate change point of view, this is potentially very bad news.

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Question

• a.Dieter Helm outlines three related, competing Peak Oil hypotheses. What are they and what do they have in common?
• b.He argues that it is not the supply of oil that is limited but our technologies. Why does he feel that technology will improve?
• c.What are the two key ways in which he thinks new technologies can increase supply?

Answer

• a.The three competing Peak Oil hypotheses he describes are:
  • the Earth's oil resources are physically limited
  • oil that we need to use now is controlled by a small number of countries, which may restrict supplies for political reasons
  • inevitably demand for oil will rise so fast that supply will not keep up - making the price of oil soar.
  The starting point for all these ideas is that there is a physical limit to the amount of oil we can produce from the Earth.
• b.He argues that as the price of oil rises, investment in new technologies becomes economic.
• c.The two key areas in which he thinks technology will improve are:
  • getting more out of existing conventional wells, where we currently leave up to 50% of the oil in the ground
  • extracting unconventional oils such as shale oils.

Part II

Shaun Chamberlin is an environmental activist, author and policy advisor. He was a pioneer of the Transition Towns movement and sits on the council of the campaigning organisation World Development Movement. He has also served as an advisor to the UK Department of Energy and Climate Change and co-authored the All Party Parliamentary Group on Peak Oil's 2011 report into energy rationing. He argues that Peak Oil is a reality now.

Listen to the 5-minute extract of the interview and then answer the following questions.

Courtesy of Jonathan Helm.

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Transcript: Audio 2

Shaun Chamberlin

I'm Shaun Chamberlin. I co-authored a report for the All Party Parliamentary Group on peak oil, and I run the campaign for TEQs, which is the energy rationing system being discussed around the world.

Peak oil is based on the discovery, from experience, that for any given oilfield the production from that oilfield will increase over time, and then eventually reach a peak, and decline from that point in terms of the flow rate that's coming out of that oilfield. And the same is true of a region of oilfields or a country or, indeed, global oil production. And so the term peak oil usually refers to that, that global peak in oil production. I think crucially one of the things that's often said about peak oil is that it's when, when half the oil's been extracted, but that isn't necessarily true. It was probably true more when conventional oil made up the bulk of oil production. But now if you look at things like, for example, oil shale there are vast reserves of this stuff but the extraction rate from oil shale is very low for other reasons so, for example, the amount of water that's required to produce that. It's the flow rate that determines what's actually available to society to use, and reserves are just one limiting factor on that. We often say in peak oil terms that it's not the size of the tank that matters, it's the size of the tap that matters.

I like to challenge people when they talk about peak oil theory or peak oil hypothesis, because in the present we can say it's not really a theory or hypothesis, it's an observable fact. I mean the US oil production peaked in 1971; UK oil production peaked in 1999; global oil production has sort of levelled off over the last six or seven years. And, fundamentally, oil is a finite resource clearly, and so it's obvious that there will come a time when production declines over time. But in terms of looking to future scenarios and future impacts of, of peak oil, one of the key things was in 2005 the US Department of Energy produced a report, led by a guy called Robert Hirsch, and he spoke about economic, social and political impacts that would be abrupt, revolutionary, and not temporary.

Now, there are many, many different scenarios as to how peak oil and its implications could play out, but there are some undeniably important facts. I mean energy is probably best thought of as our ability to do stuff; that's fundamentally what it is. And so you'll find some kind of energy supply in the supply chain of every company and every activity that goes on. It obviously has a huge impact on the economy. If, if energy prices are increasing dramatically, as they have, then there's a complex relationship, and an important relationship, between that and the strength of the global economy generally.

The one absolutely core fact that really emphasises peak oil and its importance is that if you look at the energy content of petrol then a fill-up of petrol for a car, say 40 litres of petrol, is equivalent to four years of manual labour by a person, in terms of its energy content, and other things you can do with it, and yet, you know, we're paying for that maybe fifty quid. You know, you see if you can find someone who'll do four years of manual labour for you for fifty pounds and it's very easy to see why we've industrialised everything we can and, and powered it with fossil fuels.

And it's also I think crucial to look at the interplay with climate change, because there's a sort of a debate around whether peak oil is, is a good thing or a bad thing in terms of climate change. Because some people say well, you know, if we don't have as many fossil fuels, great, you know, we're not going to burn as many fossil fuels so that improves the climate change situation. Whereas others would say, oh my God, you know just at the point where we've got this huge challenge of climate change, we've also got this problem that's going to limit our ability to act and limit our ability to adapt and, you know, it's going to undermine our society's ability to do things about it.

And this is where I think it's really important to recognise that peak oil is no longer a future issue. This is something that's already shaping our world. I mean when I first started looking into peak oil around, around the turn of the century, the oil price had never been over $40 a barrel, except for during the '70s oil crisis when it, when it shot up. But that was a short-term political situation whereby certain oil producing and exporting countries reduced their production, reduced their exports for political reasons. After that crisis, it dropped back down and remained around $15-30 a barrel until I think around 2003. And actually I remember at one point in 1999 the oil price was under $10 a barrel, that recently, and yet now the average price last year, the average price, not the peak, was over $100 a barrel. And I remember 10 years ago we were told we were absolute nutcases for talking about the possibility of $100 a barrel, where that would never happen, and now it's absolutely normal and it's absolutely what everyone expects to happen.

You've got the International Energy Agency, for example, which is the leading global authority on energy absolutely acknowledging that we're facing this huge problem here. Their chief economist said a couple of years ago that we, we absolutely need to leave oil before it leaves us, and we have sounded the warning; these were his exact words,

It's hard to find a credible observer who doesn't believe that we're going to peak by 2030, you know that's the, that's a real outlier. You know some of the big sort of oil companies who consider it in their best interest to deny that this is a problem, they talk about peak oil by 2030. But even if that were true, it would still be time to be doing something about it right now.

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Question

• a.Dieter Helm outlined three related Peak Oil hypotheses. Which sort of Peak Oil arguments does Shaun Chamberlin put forward and what sort of evidence does he draw on?
• b.Why does he argue that 'It's not the size of the tank that matters, it's the size of the tap'?

Answer

• a.Shaun Chamberlin's arguments largely focus on the physical limitations of oil supply - the evidence he draws on are past levels of oil production.
• b.He feels that Peak Oil issues are related to the rate at which oil is extracted from the ground, rather than how much is stored there. He argues, for instance, that the extraction of oil from oil shales is a very slow process - limiting the rate at which oil can be produced from this source.

If you are interested to read more about Shaun Chamberlin's views, he writes at www.darkoptimism.org.

Part III

Question

Having listened to the two commentators, and read this course, where do you stand on the Peak Oil question? From what you know, do you think it is a real issue? In your opinion does it affect the question of whether or not we should be trying to live without oil? (Answer in about 150 words)

Answer

Your answer here will clearly depend on your point of view. Here is one possible answer, though you may take a different stance.

Supplies of conventional oil are likely to peak in the near future, but if we are prepared to invest in expensive technologies to extract unconventional oil like shale oil, we will be able to keep supplies going for a very long time. This will mean that the prices of oil products are likely to remain high. The extraction of unconventional oil is likely to have environmental consequences, for example the extraction of shale oil is a very dirty process. The question of whether or not oil supplies will peak is not relevant when we consider the issue of anthropogenic global warming - we need to find ways to supply our energy needs without burning fossil fuels. For this reason the question of if we can live without oil and other fossil fuels is important, whether or not supplies are about to decline.

Conclusion

• Oil plays a central role in the modern world.
• The major use of oil is as a cheap source of transport fuel. We rely on cheap transport to move around both goods and people. Cheap oil-driven transport plays an almost invisible role in the manufacture of all modern goods.
• A smaller but vitally important role of oil is as a source of modern materials, particularly plastics.
• The need to develop sustainable alternatives to oil is driven by two major factors. The first is the fact that oil is becoming harder to find and extract and is likely to become more expensive, both economically and environmentally. The second is that the combustion of oil is a major contributor to anthropogenic global warming.
• Alternative sources of crude oil are available, but this non-conventional oil is difficult to obtain and often its extraction can cause greater environmental damage than that of conventional oil.
• Combustion of oil as fuel also gives rise to other forms of pollution: for example, carbon monoxide, nitrogen oxides, particulates, VOCs and tropospheric ozone.
• Chemical compounds are described using chemical formulas. For example, methane has the chemical formula CH₄, meaning each molecule of methane consists of one atom of carbon and four atoms of hydrogen.
• Chemical change is described using chemical equations. Full balanced chemical equations include the state (gas, liquid or solid) of the substances involved, and can be indicated by using an 'equals' sign. Unbalanced chemical equations use an arrow.

Acknowledgements

This course was written by John Baxter

This free course is adapted from a former Open University course Living without oil (S176).

Course image: Febe Patty in Flickr made available under Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Licence.

The material acknowledged below is Proprietary, used under Licence and not subject to Creative Commons Licence. See terms and conditions.

Grateful acknowledgement is made to the following:

Figures

Figure 2 (v) Ian Britton/freefoto.com (http://creativecommons.org/ licenses/ by-nc-nd/ 3.0/; Figure 5 © Cordelia Molloy/Science Photo Library; Figure 10: © Getty Images; Figure 11 courtesy of Gazprom.

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This free course is adapted from a former Open University course called 'Living without oil (S176)'.