Cubic mile of oil

The cubic mile of oil (CMO) is a unit of energy. It was created by Hew Crane of SRI International to aid in public understanding of global-scale energy consumption and resources.^[1]

Significant sources of energy include oil, coal, natural gas, nuclear, hydroelectric, and biomass (primarily the burning of wood). Other energy sources include geothermal, wind, photovoltaic, and solar thermal. The various energy units commonly used to measure these sources (e.g., joules, BTUs, kilowatt hours, therms) are only somewhat familiar to the general public,^[2] and their relationships can be confusing.^[3] These common energy units are sized for everyday activities (a joule is the energy required to lift a small apple one meter vertically). For regional, national, and global scales, larger energy units, such as the exajoule, the billion barrels of oil equivalent (BBOE) and the quad are used. Derived by multiplying the small common units by large powers of ten these larger units pose additional conceptual difficulties for many citizens.^[4]

Crane intended the cubic mile of oil to provide a tangible scale for comparing the contributions of these diverse energy components as a percentage of total worldwide, energy use.

The global economy consumes approximately 30 billion barrels of oil (1.2 trillion U.S. gallons or 4.8×10⁹ m³) each year.^[5] Numbers of this magnitude are difficult to conceive by most educated people.^[4][6] The volume occupied by one trillion U.S. gallons is about one cubic mile. Crane felt that a cubic mile would be an easier concept for the general public than a trillion gallons.

Definition and energy equivalents

The CMO is the energy released by burning a cubic mile of oil. Conversions to other units may be calculated based on the barrel of oil equivalent (BOE), an approximation of the energy released by burning one 42-US-gallon barrel of crude oil. Since one BOE is about 5.8×10⁶ BTU^[7] and one cubic mile is about 2.62×10¹⁰ barrels:^[8]

1 CMO	≈ 1.6×1020 joules
		= 160 exajoules
	≈ 4.454×1013 kilowatt-hours
		= 44.54 petawatt-hours
	≈ 1.52×1017 BTU
		= 152 quads
		≈ 150  trillion (1012) cubic feet of natural gas
	≈ 2.62×1010 BOE

Annual energy consumption by source

2008 worldwide renewable-energy sources. Source: REN21^[9]

The world consumes approximately 3 CMO annually from all sources. The table ^[10] emphasizes the small contribution from alternative energies in 2006.

Source	CMO/yr
Oil	1.06
Coal	0.81
Natural gas	0.61
Biomass	0.19
Nuclear	0.15
Hydroelectric	0.17
Geothermal	<0.01
Wind+Photovoltaic+Solar thermal	<0.005

Global energy reserves

Proved oil reserves are those that can be extracted with reasonable certainty under existing conditions using existing technology. Global proved oil reserves are estimated at approximately 1,300 billion barrels (210×10^⁹ m³).^[11] This corresponds to roughly 43 cubic miles, or 43 CMO. At the current rate of use, this would last about 40 years. Technological advances, new discoveries, and political changes may lead to additional proved oil reserves in the future. Concurrently, the International Energy Agency predicted in its 2005 World Energy Outlook that the annual consumption will increase by 50% by 2030.^[12] Other fossil fuels provide additional reserves needed to provide the 1.42 CMO they currently supply:

• Natural gas reserves total 42 CMOs (69 years at current consumption)
• Coal reserves total 121 CMOs (150 years at current consumption)
• Tar sands and other unconventional fossil sources have unknown reserves

Replacement of oil by alternative sources

While oil has many other important uses (lubrication, plastics, roadways, roofing) this section considers only its use as an energy source.

The CMO is a powerful means of understanding the difficulty of replacing oil energy by other sources. SRI International chemist Ripudaman Malhotra, working with Crane and colleague Ed Kinderman, used it to describe the looming energy crisis in sobering terms.^[13] Malhotra illustrates the problem of replacing one cubic mile of oil with energy from five different alternative sources. Such a replacement requires long and significant development.

Allowing fifty years to develop each replacement, one cubic mile of oil could be replaced by any one of these developments:

• 4 Three Gorges Dams,^[14] developed each year for 50 years, or
• 52 nuclear power plants,^[15] developed each year for 50 years, or
• 104 coal-fired power plants,^[16] developed each year for 50 years, or
• 32,850 wind turbines,^[17][18] developed each year for 50 years, or
• 91,250,000 rooftop solar photovoltaic panels^[19] developed each year for 50 years

The energy produced is the power rating of the source multiplied by the duration it is operational. These comparisons take into account the variability of available power (solar panels work only during the day, turbines work only when the wind blows).

The environmental, social, and financial costs of such development projects are immense:

• The Three Gorges Dam is the world's largest, flooding 632 km², displacing 1.25 million people, and costing roughly US$30 billion.
• A nuclear power plant produces hazardous radioactive waste, raises fears of radiation or nuclear proliferation, requires 10 years to construct for a 40 year lifetime, occupies about 4 km², and may cost upwards of US$5 billion.
• A 500 MW coal-fired power plant may contribute to acid rain, global warming, and air pollution, occupies about 2 km², may obtain its fuel via controversial methods such as mountaintop removal, and costs about US$650 million.
• A large wind turbine requires a location with an abundance of steady wind, may be visually obtrusive, can interfere with aviation, needs about 0.16 km² to avoid interfering with adjacent turbines, and costs about US$2 million.^[20]
• A 2.1 kW rooftop solar array requires technical skills for installation, needs a sunny location, presents few aesthetic or environmental problems, covers about 14 m², but costs around US$15,000.

Alternative Replacements for one CMO

Source	Number	Cost (US$1 trillion)	Area
			(km2)	(sq mi)
Dams	200	6	1,264,400	488,200
Nuclear plants	2,600	13	10,400	4,000
Coal plants	5,200	3.4	10,400	4,000
Wind turbines	1,642,000	3.3	273,667	105,663
Rooftop photovoltaics	4,562,500,000	68	63,875	24,662

For comparison, US$3.2 trillion is the approximate gross domestic product of Germany, China, or the United Kingdom. The total land area of New Zealand is approximately 270,000 square kilometres (100,000 sq mi).^[21]

At a 2008 market price of US$120 per barrel (US$750/m³), the cost of one CMO was about US$3 trillion.

References

1. ^ Crane, Hewitt; Edwin Kinderman and Ripudaman Malhotra (June 2010). A Cubic Mile of Oil. Oxford University Press USA. ISBN 9780195325546. 
2. ^ ""Energy and the Environment" - The Basics". 2007 New Hampshire Envirothon. http://www.nhacd.org/docs/welcome_energy_basics.pdf. Retrieved 2009-01-25. 
3. ^ "The mixture of terms for essentially one entity (energy) leads to confusion, especially among citizens who need to be aware, now more than ever, of energy consumption patterns." http://www.justjoules.org/
4. ^ ^{a b} Wenner, Jennifer M.. "Big Numbers and Scientific Notation". Teaching Quantitative Skills in the Geosciences. University of Wisconsin-Oshkosh. http://serc.carleton.edu/quantskills/methods/quantlit/BigNumbers.html. Retrieved 26 December 2009. 
5. ^ Aleklett, Kjell (2005-04-25). "The oil supply tsunami alert". Energy Bulletin. http://www.peakoil.net/Oil_tsunami.html. Retrieved 2008-12-06. 
6. ^ Paulos, John allen (1988). "Innumeracy". New York: Hill and Wang. pp. 135. ISBN 0809074478. 
7. ^ http://www.irs.gov/pub/irs-drop/n-99-18.pdf
8. ^

   1 mi	= 5280 ft
   	= 63360 in
   1 bbl	= 42 US gal
   1 US gal	= 231 cu in
   thus
   1 cu mi	= 633603⁄42 × 231 bbl
   	≈ 2.6217074939×1010 bbl

9. ^ Renewables Global Status Report 2009 Update (PDF).
10. ^ Can renewable energy make a dent in fossil fuels? | Green Tech - CNET News
11. ^ "World Proved Reserves of Oil and Natural Gas, Most Recent Estimates". Energy Information Administration. 2008-08-27. http://www.eia.doe.gov/emeu/international/reserves.html. Retrieved 2008-12-06. 
12. ^ "World Energy Outlook 2005" (pdf). International Energy Agency. 2005. pp. page 43. http://www.iea.org/textbase/nppdf/free/2005/weo2005.pdf. Retrieved 2008-12-06. 
13. ^ Joules, BTUs, Quads-Let's Call the Whole Thing Off - IEEE Spectrum
14. ^ at rated 18 gigawatts
15. ^ at 1.1 gigawatts, such as the Diablo Canyon Power Plant
16. ^ at 500 megawatts
17. ^ A large turbine with 70-100 meter blade span, rated at 1.65 MW.
18. ^ General Electric Wind Turbines
19. ^ a typical 2.1 kW panel
20. ^ http://www.sunjournal.com/story/226451-3/Business/Wind_turbine_shortage_continues_costs_rising/
21. ^ "New Zealand Facts". http://www.ace.net.nz/larryogden/facts.html. Retrieved 22 January 2011. 

External links

• 'Doug Englebart's colloquium' Hewitt Crane discusses the state of the world's energy supply