Sections
Caption: "Lightning over the outskirts of Oradea, Romania, during the August 17, 2005 thunderstorm which went on to cause major flash floods over southern Romania."
Electrical potential energy of charge separation in the atmosphere is converted into the energy of electromagnetic radiation, heat, and sound.
Credit: Mircea Madau, User:Lucas.
Linked source: Wikipedia image http://en.wikipedia.org/wiki/File:Lightning_over_Oradea_Romania_zoom.jpg.
Permission: Public domain at least in USA.
Scientific notation is a way of expressing very large and very small numbers.
It's vital in a world where quantities that must be understood and used in calculations come in vastly different sizes.
We have already used it a bit and many people may already know it well.
And it is really simple.
One expresses a number as a coefficient times a power of ten:
a*10**b in my old fortran way.
a*10b in better format.
a is the coefficient which is between 1 and 10 in normalized Scientific notation.
Coefficient seems most obvious term to use, but
older works used the terms
significand
or
mantissa.
b is the exponent.
10 is ten.
Examples of
scientific notation
with some example
International System of Units (SI) prefixes and SI units.
---------------------------------------------------------------------------------
Number SI prefix
-----------------------------
SI energy unit SI power unit
(power is
energy per
unit time)
---------------------------------------------------------------------------------
1 = 1*10**0 = 10**0 (nada) joule (J) watt (W) (joule/s)
(One can omit
the coefficient
if its 1.)
10 = 10**1 deka (da)
100 = 10**2 hecto (h)
1000 = 10**3 kilo (k) kilojoule (kJ) kilowatt (kW)
1 000 000 = 10**6 mega (M) megajoule (MJ) megawatt (MW)
(The number of digits of ordinary notation
after the lead one is the exponent
of standard scientific notation number.)
1 000 000 000 = 10**9 giga (G) gigajoule (GJ) gigawatt (GW)
1 000 000 000 000 = 10**12 tera (T) terajoule (TJ) terawatt (TW)
10**15 peta (P) petajoule (PJ) petawatt (PW)
10**18 exa (E) exajoule (EJ) exawatt (EW)
10**21 zeta (Z) zetajoule (ZJ) zetawatt (ZW)
10**24 yota (Y) yotajoule (YJ) yotawatt (YW)
(Not Yoda.)
1 day = 86400 s = 8.64*10**4 s
1 Julian year = 365.25 days
= 3.15576*10**7 s
= approx pi*10**7 s
Age of the universe = 14 Gyr
= 4.4*10**17 s
-----------------------------
SI length Example scale
1 = 10**0 (nada) meter (m) human
0.1 = 10**(-1) deci decimeter (dm) guinea pig
Credit: Wikipedia contributor Sandos. According to Wikipedia permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version.
Download site: Image:Guinea 1.jpg.
0.01 = 10**(-2) centi centimeter (cm) Etruscan shrew
0.001 = 10**(-3) milli millimeter (mm) fine marks on a meter stick
10**(-6) micro micron (mu-m) microbe
``Low-temperature electron micrograph of a cluster of E. coli bacteria, magnified 10,000 times. Each individual bacterium is oblong shaped.'' Wikipedia: Image:E coli at 10000x, original.jpg.)
Credit: Eric Erbe, digital colorization by Christopher Pooley, both of USDA, ARS, EMU. This image is in the public domain because it contains materials that originally came from the Agricultural Research Service, the research agency of the United States Department of Agriculture See more images at ARS images.
Download site: Wikipedia: Image:E coli at 10000x, original.jpg.
10**(-9) nano nanometer (nm) nanotechnology
This is really
sub-micron (i.e., hundreds
nanometers) technology
I think, but that doesn't
sound sexy to research funders.
10**(-10) Angstrom (A) atom
10**(-12) pico picometer (pm)
10**(-15) femto femtometer (fm) atomic nucleus
(fermi to
physicists)
---------------------------------------------------------------------------------
How does one multiply and divide using
scientific notation?
One multiplies and divides the coefficients and adds and subtracts the components.
In general for multiplication: a*10**b * c*10**d = (a*c)*10**(b+d)
Examples:
3*10**3 * 3*10**3 = 9*10**6
7*10**4 * 5*10**6 = 35*10**10 = 3.5*10**11
In general for division: (a*10**b)/(c*10**d) = (a/c)*10**(b-d)
Examples:
( 9*10**48 )/( 3*10**(-24) ) = 3*10**(48-(-24)) = 3*10**72
( 4*10**12 )/( 8*10**24 ) = 0.5*10**(-12) = 5*10**(-13)
``And that's all folks for scientific notation."---as
Bugs Bunny
used to say.
Caption: "Still frame from the animated cartoon "Falling Hare" (1943).
A classic Bugs Bunny cartoon.
Bugs was clearly interested in energy and power.
The copyright was not Public domain. renewed and thus the cartoon has fallen into the public domain. This restored shot is taken from the version found on the Looney Tunes Golden Collection DVD set. The unrestored version can be seen at the Internet Archive, while the restored version can be seen on YouTube. Bugs is lying on his back, propped up on his left elbow, reading a book titled Victory Thru Hare Power. This title refers to the propaganda book (and Walt Disney's film of the same name) Victory Through Air Power (1943)."
Credit: Looney Tunes
Linked source: Wikipedia image "http://en.wikipedia.org/wiki/File:Falling_hare_bugs.jpg.
Public domain at least in USA.
But energy is such an abstract quantity in the first place, why not use standard units for energy in all cases?
Why not use SI (Systeme International) (AKA Metric System) energy units?
"Map of the world where red represents countries which do not use the metric system"
Linked source: Wikipedia image http://en.wikipedia.org/wiki/Image:Metric_s ystem.png.
Author: User Donovaly.
Public domain.
By always using SI energy units, people we get a good sense of the relationships between different quantities of energies in different contexts.
But no---there is a plethora of weird energy units for different contexts for which the conversion factors are NOT obvious and are tricky.
Even people writing articles on energy often merrily trip between relatively incomparable units without apology---and without shame.
So let's put some of these weird energy units in relation to SI energy units so that we know what people are talking about.
The instructor feels a bit peevish/cranky on this subject.
We are NOT going to be exhaustive.
See Conversion of Units (Wikipedia) for that.
-----------------------------------------------------------------
Unit Conversions
-----------------------------------------------------------------
Weird unit In convenient Comment
SI units
-----------------------------------------------------------------
1 food calorie 4.1868 kJ Typical human food needs are
in the range 2000--3000 food calories.
1000 food calories 4.1868 MJ per day. That turns into 8--12 MJ.
So the megajoule is a perfectly
convenient unit for food energy.
It's better than food calories.
1 calorie 4.1868 J A food calorie is really a kilocalorie.
The real calorie is the amount of
energy needed to raise the temperature
of one gram of water by 1 degree Celsius.
Various versions exist because the
amount of energy needed varies
with conditions. The shown one
is the International Steam calorie
(See Wikipedia: Calorie).
1 kilowatt-hour 3.6 MJ The kilowatt-hour is hybrid unit
that is (kilojoule/second)*hour.
The MJ is good-sized replacement.
1 Btu 1.0545 kJ British thermal units of slightly
different size still linger around.
Kilojoules can obviously replace them.
1 kg of gasoline 44--45 MJ About 5.5 times daily human
food needs. You could live
on a about 0.2 kg of gasoline per day.
1 kg of oil 41.868 MJ This is standard definition
since the chemical energy content
of oil varies. It looks like the
calorie digits.
tonne oil equivalent 41.868 GJ See Ton of oil equivalent.
(toe) A tonne is a metric ton (1000 kilograms).
It really ought to be called a
megagram (Mg).
barrel (bl) of oil 6.12 GJ This is approximate. The oil
equivalent industry insists are reporting
oil in barrels---though no one
has put oil in barrels in a
jillion years (to be precise).
Why not just report oil quantities
in energy equivalent since energy
content is the key issue.
1 Mbl of oil 6.12 PJ World daily consumption is often
given in mbls.
1 Gbl of oil 6.12 EJ World yearly consumption is often
given in Gbls.
tonne coal equivalent 29.3076 GJ This must be a standard definition
since the chemical energy content
of coal varies. You can see one
the reasons why people prefer oil
to coal. Oil has a higher energy
density typically. (See tonne oil
equivalent just above.)
-----------------------------------------------------------------
A pint of Guinness.
But it's too early in the day.
Credit: Jon Sullivan of PD Photo.org. The author has released the image into the public domain.
Download site: Wikipedia: Image:Ireland 37 bg 061402.jpg.
So about how much is 198 food calories in megajoules?
Answer 1---but it's hard to figure out isn't it?
The trick is to use factors of unity and algebra.
4.1868 MJ = 1000 food calories.
Therefore
4.1868 MJ
1 = ------------------
1000 food calories
You can always multiply anything by 1 without changing
its size.
Thus
198 food calories = 198 food calories * 1
4.1868 MJ
= 198 food calories * ------------------
1000 food calories
= approx 0.8 MJ .
So 10 pints of Guinness
provides you with all the energy you need in a day.
But man does not live by energy alone.
In any case, alcohol is slightly toxic and has psychoative effects.
Remember friends don't let friends drive drunk.
Caption: "Ratcliffe Power Plant,
Nottinghamshire" (2006mar20).
The mist is probably smoke, but some could be just water vapor from the cooling towers.
It looks like some hypertrophied Satanic mill from the Industrion Revolution.
I thought this was a nuclear power station, but it's actually a coal-fired power station.
Credit: Alan Zomerfeld.
Linked source: Wikipedia image .
Licensed under the Creative Commons Attribution ShareAlike 2.5.
Power is almost always quoted in watts or some standard multiple:
Watts we need for light-bulbs. Actually, only about 5 % of the power of an incandescent light bulb passes through the state of visible light (Wikipedia: Incandescent light bulb).
For 2005, worldwide commercial energy consumption rate of the humankind has been calculated to be 16 terawatts (= 16 x 10**12 W) ( Wikipedia: World energy resources and consumption).
electrical horsepower = 746 W = 0.746 kW exactly.James Watt (1736--1819) (who developed the much improved steam engine) invented horsepower to help market his invention (See Wikipedia: History of the term "horsepower").
"Chantrey's statue of James Watt, the Scottish inventor" (1986): Linked source: Wikipedia.
Humans can exert 1.2 hp briefly and 0.1 hp for long periods ( Wikipedia: History of the term "horsepower")---but this is on objects outside of the human body---on themselves (running etc.) humans can do much better (Smil 2006, p. 61).
The Shire horse is the largest horse breed on average.
An average height at the withers---I've no idea---is 1.78 m (5'8'') and the record is 2.2 m.
A typical stallion mass is a about 0.9 megagrams (i.e., 0.9 metric tonnes).
Maybe a Shire horse would think of 1 horsepower as a mere foal frolic.
Credit: An employee of United States Department of Agriculture. As a work of the U.S. federal government, the image is in the public domain.
Download site: Wikipedia: Image:ShireDraftHorse.jpg.
Caption: "Shire horses at Avon Valley Country Park, Bristol, England. Named Misty and Molly, they are six years old." (2007aug)
Author: Adrian Pingstone
Linked source: Wikipedia image http://en.wikipedia.org/wiki/Image:Shire_horses_arp.jpg.
Public domain.
Caption: "Vehicles per thousand people." (2008apr01):
----------------------------------------------------------------
Color Cars per thousand persons
----------------------------------------------------------------
black 600+
darkest green 501--600
darker green 301--500
dark green 151--300
green 101--150
light green 61--100
lighter green 41--60
lightest green 21--40
still lighter green 11--20
almost not green at all 0--10
grey nearly none I guess
----------------------------------------------------------------
In the US every
person owns at least 60 % of a car.
Author: User: TastyCakes.
Linked source: Wikipedia image http://en.wikipedia.org/wiki/Image:World_vehicles_per_capita.svg.
Public domain.
Here's another question for the class.
The world and continent population growth with projections for the future.
The vertical scale is population in millions. The scale is logarithmic: factors of 10 are one unit or 1 dex. The scale shows 3 and a smidgen dex.
The horizontal scale shows year.
The researchers who make the projections do their best, but the projections are still very uncertain.
The data was drawn from the United Nations: Department of Economic and Social Affairs: Population Division with the specific page being World Population Prospects: Thw 2006 Revision World: Population Database.
Credit: Wikipedia contributor. According to Wikipedia permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version.
Download site: Wikipedia: Image:World population (UN).svg.
What approximately is the average power per capita?
Answer 3 is right.
Behold:
(16 TW)/(6.8 gigacapita) = (16*10**12 W)/(6.8*10**9 capita) = approximately 2*10**3 W/capita.
Well 2*10**3 W is more than most light bulbs, but only by
an order of magnitude (i.e., a factor of 10 or so).
I wonder why we have to be counted by our heads?
The Sun is pretty complex, but I'd guess it's still less complex than a single living cell.
Caption: "This diagram shows a cross-section of a solar-type star." (2006oct).
In the center the Sun is of order 15 MK (i.e., 15 million kelvins) in temperature.
This is where nuclear fusion generates the power output of the Sun that emerges as electromagnetic radiation.
There are several fusion reaction chains.
The net effect of the most important one for the Sun is:
4*11H (4 hydrogen nuclei)
----> 24He (1 He nuclei) + 2*positrons + 2*neutrinos + 2*gamma rays
The heat energy output for this chain is
is about 0.272 W/m**3 in the Sun's core---which
is pretty small---but there is a lot of
volume in the Sun's core.
The total power output of the Sun in electromagnetic radiation is 3.846*10**26 W which in astro-jargon we call the Sun's luminosity.
The energy is transported from the core to the surface by radiative transfer and near the surface by convection predominantly.
Convection is a macroscopic turbulent means of energy transport.
The tops of the convective cells make the solar granules: these are the grainy patches on the visible surface of the Sun.
Convection happens in boiling pans of water.
It's goes extensively in the Earth's atmosphere, but not often noticed since air is invisible usually.
At the Sun's suface, the Sun's energy streams away as electromagnetic radiation.
Why does the energy flow from the core to space?
Thermal energy spontaneously flows from hot to cold.
This is a basic process that can be seen as a consequence of the 2nd law of thermodynamics which we discuss in Lecture Thermodynamics.
The Sun's core is hot (15 MK) and space is cold.
The temperature of the main component of energy in space is, in fact, 2.725 K (or 2.725 kelvins above absolute zero).
This is the temperature of the cosmic microwave background radiation (CMB) that permeates all space and is a relic of the Big Bang.
Author: Project leader: Dr. Jim Lochner; Curator: Meredith Gibb; Responsible NASA Official:Phil Newman.
Linked source: Wikipedia image http://en.wikipedia.org/wiki/Image:Sun_parts_big.jpg.
Public domain.
This is usually specified by giving the solar constant.
Solar constant is the solar electromagnetic radiation (light) power per unit area (perpendicular to the Earth-Sun line) at the top of the Earth's atmosphere.
The solar constant 1978--1999.
The solar constant is the power per unit area (perpendicular to the Earth-Sun line) at the top of the Earth's atmosphere. The mean value is about 1366.5 W/m**2.
In other words, a bit less than 2 horsepower per square meter.
During a full sunspot solar cycle the value varies by only by 0.1 percent from maximum and minimum. The near constancy of the solar constant is good for life on Earth.
Actually the annual variation do to the variation in the Earth-Sun distance has been removed from this plot.
This is the plot that one would get at the mean Earth-Sun distance.
The solar constant varies over about 6.9% during a year from a low of 1321 W/mē in early July when Earth is farthest from the Sun to 1412 W/mē in early January when Earth is closest to the Sun (Wikipedia Solar Constant).
Credit: NASA.
The solar spectrum log-log plot.
Here we have a black-body radiation fit to the solar spectrum (dashed line), the solar spectrum above the atmosphere (dark blue), and the relative solar spectrum at the Earth's surface in cloud-free conditions (light blue). The wavelength range extends from far UV to far IR.
Black-body radiation is the spectrum emitted by a body that had a single temeperature: i.e., was in thermodynamic equilibrium.
Because of the small scale, absorption lines in the spectrum have been mostly smoothed out. A larger scale would show many them.
Note that the Sun spectrum peaks in the visible.
Note also that the Earth's atmosphere is opaque in the UV and in many broad bands in the IR, but the visible is pretty transparent.
The transparent bands are sometimes called WINDOWS in astro jargon.
Credit: US Naval Research Laboratory, Judith Lean; download site NASA.
A good site for the solar spectrum is NOAA's The Solar Spectrum and Terrestrial Effects site.
So the capture cross section of the Earth is pi*R**4.
But this must be spread over the whole surface area which is 4*pi*R**4.
So the fraction of the solar constant to spread over the Earth is
pi*R**4
----------- = 1/4
4*pi*R**4
So the top of the Earth's atmosphere gets on average about 340 W/m**2.
But only about half of this reaches the ground. The rest is reflected above the ground.
Thus we arrive at 170 W/m**2 (Smil 2006, p. 27).
Of course, we actually can't capture 170 W/m**2.
Photovoltaics can't capture 100 % of insolation.
Currently, 10% or so is commercially feasible, but much higher efficiencies are possible.
Experimental high efficiency solar cells have reached 43 % for a current record.
So tens of W/m**2 of solar energy is possible.
On the other hand, biomass from dryland typically yields only about 0.5 W/m**2 and tops out about 1 W/m**2 (Smil 2003, p. 264).
Biofuels, as we'll discuss in lecture World Energy Resources and Consumption, are NOT going to be a dominant fuel of the future.
Caption: "US annual average solar energy received by a latitude tilt photovoltaic cell (modeled)." (2005dec).
The weird hydrid unit kW-h/m**2/day = 40 W/m**2
So desert and arid regions the US south-west typically get 240 W/m**2 or more on average.
Of course, none of this energy comes at night which is a limitation for solar power.
Author: Work of the US Federal Government
Linked source: Wikipedia image http://en.wikipedia.org/wiki/Image:Us_pv_annual_may2004.jpg.
Public domain.
This is vastly more than the 16 TW of commercial power that humankind currently uses.
Don't reach for your calculators.
Answer 3.
Behold:
(89000 TW)/(16 TW) = approximately (90/16)*10**3 = 5500.
This is another one of those mesmerizing numbers.
For all kinds of obvious reasons, we can only ever harvest a tiny fraction of this as commercial power.
But even a tiny fraction would be all the commercial power we can currently imagine needing.
Many people think that is feasible and the dominant source of commercial power in the future will be solar power from photovoltaics or solar-powered heat engines.
Caption: "On 140 acres of unused land on Nellis Air Force Base, Nev., 70,000 solar panels are part of a solar photovoltaic array that will generate 15 megawatts of solar power for the base." (2007dec)
``Nellis'' reminds me of Nellis St., Woodstock, Ontario where my mother's family used to live.
Author: U.S. Air Force photo/Airman 1st Class Nadine Y. Barclay.
Linked source: Wikipedia image http://en.wikipedia.org/wiki/Image:Giant_photovoltaic_array.jpg.
Public domain.
A more immediate question is what fraction of commercial power will be solar power 40 years hence---or maybe what fraction ought to be solar power 40 years hence?
A Solar Power Grand Plan (Zweibel et al. 2008, Scientific American, January, p. 64) has been proposed which would make solar power the dominant power in the US by 2050.
Caption: "The Burghers of Calais by Auguste Rodin, Taken April 2006 by AndyZ at Hirshhorn Sculpture Garden" (2006apr)
According to legend (with maybe some history) The Burghers of Calais (the six burghers of Calais) were volunteers for subjection to the revenge Edward III of England wished to visit on city of Calais in 1347. His wife Philippa of Hainault pleaded successfully for their lives.
Author: User: AndyZ.
Linked source: Wikipedia image http://en.wikipedia.org/wiki/Image:Burghers_of_Calais_Hirshhorn.jpg.
Public domain.
We intake food which carries chemical energy and our bodies overall transform this energy to kinetic energy, body heat, and infrared light.
We can be seen in the dark by it---like this poor mouse.
Caption: "Thermographic of a snake eating a mouse."
This an infrared image in false color, of course.
Darker is colder: i.e., longer wavelength.
Snakes are cold-blooded.
Not to mention snake-owners who feed living mammals to snakes.
Credit: Arno / Coen.
Linked source: Wikipedia image http://en.wikipedia.org/wiki/File:Wiki_snake_eats_mouse.jpg.
Permission: Use under GNU Free Documentation License.
Actually, an anti-exhaustive presentation.
A couple of definitions can lead us off:
Basal in this context means base or reference.
BMR women 55--80 W.
BMR men 60--90 W.
Low/high food energy rate for a sedendary/very active human
= 2000 / 4000 food calories/day
= 8.4 / 16.8 MJ/day
= 97 / 194 W
The low food energy rate for humans is only a bit above
the BMR.
So for sedentary people, most of food energy goes
into existing.
Thinking doesn't take much energy.
A typical healthy adult has a sustained metabolic scope of above 10
for some time (hours?) for example when running or swimming.
This is a power of order 800 W = 0.8 kW and is more than
1 horsepower = 0.746 kW.
But note that most of this power is going into moving the
human body and not in moving other stuff which is what we expect
of horses.
Elite athletes and traditional-society hunters can probably
sustain 1.75 kW for hours??? or a metabolic scope of 20 or more
(Smil 2006, p. 61).
This is actually very high among animals.
Only canids have a higher sustained metabolic scope for hours???
of activity: i.e., above 30
(Smil 2006, p. 61).
Dogs love to run, you know.
Gray wolf (Canis lupus).
But this fellow is taking it easy for the moment.
Credit: An employee of United States Fish and Wildlife Service. As a work of the U.S. federal government, the image is in the public domain.
Download site: Wikipedia: Image:Canis lupus laying.jpg.
----------------------------------------------------------------------------
Metabolizable (?) energy content of common foods
food MJ/hg The hectogram = 100 g = approximately 0.2 lb
and is of order a serving for many foods.
-----------------------------------------------------------------------------
butter 3.0
ethanol 2.93 This is just drinking alcohol in
everyday speech---we drink car fuel.
cereal grains 1.45--1.55
lean meats 0.5--1.00
fish 0.3--0.9
potatoes 0.3--0.5
fruits 0.15--0.40
vegetables 0.06--0.18
Lots of things go into making a healthy diet---chocolate,
corn dogs, etc.
But one can see why meat and grain have been big sources of food energy.
A pint of Guinness.
Butter in large amounts is too much of a good thing. But energetically you could live on 3 hg per day---if you could metabolize all that energy content which probably you cannot.
The same could be said for ethanol which is in fact slightly toxic.
Credit: Jon Sullivan of PD Photo.org. The author has released the image into the public domain.
Download site: Wikipedia: Image:Ireland 37 bg 061402.jpg.
For future lectures, we will need to know the R/P ratio---well maybe not often, but its good to know anyway.
Say you have a reserve R of a quantity at t=0.
The quantity could be oil for example.
You use it at a production (consumption) rate of P which is constant.
At any time t, your reserve is R_t < R and is given by
R_t = R - P*t .
Answer 1.
Solution by algebra:
0 = R - P*t
leads to t = R/P.
As an example, there are 1300 Gbl (gigabarrels)
of recoverable oil reserves in the world as now estimated
(
DOE: Energy Information Administration (2008), but this based
on the Oil & Gas Journal 2008jan01) and includes some tar sands oil.
World oil production (which is also pretty much consumption) is
79 Mbl/day = 79 Mbl/day * 1 * 1
= 79 Mbl/day * (1 Gbl/1000 Mbl) * (365.25 days/1 year)
= 79 *0.365.25 Gbl/year
= 29 Gbl/year
as estimated in 2005
(Wikipedia: World oil production).
See also
Energy Resources and Consumption: Oil.
Actually world oil production has been on a plateau since
about 2005 (e.g., World Oil Production Forecast - Update May 2009
by Tony Erikson).
By the by, the US consumes 7.1 Gbl/year in 2008 ( Energy Information Administration (US Gov. Agency))---which is about 1/4 of the world energy prodcution.
For the world, we find
R/P= 1300 Gbl / 30 Gbl/year = 43 years.
So in about year 2050 ...
As we indicated above, world production and consumption are about equal in the energy game.
There are some Strategic Petroleum Reserves (SPRs). ``The'' strategic petroleum reserves (SPR) is the US SPR.
The SPR is currently, 727 Mbl = 0.727 Gbl (Strategic Petroleum Reserve).
This is enough to satisfy the current world usage for 1--2 weeks.
US consumption alone is currently 7.1 Gbl/year ( Energy Information Administration (US Gov. Agency): US consumption).
So the SPR for the US alone would last only 0.1 years at current consumption.
Of course, in a national emergency oil would be rationed and the SPR would last a lot longer.
The US does have its own oil production, but it is only 1.81 Gbl/year currently ( Energy Information Administration (US Gov. Agency): US production).
This is about 6 % of the world total: US is a major oil producer---it's just a whole lot more of an oil consumer.
See also Energy Information Administration (US Gov. Agency): US imports for oil imports. Currently, the US imports 4.7 Gbl/year with the leading import source being, well, Canada with 0.9 Gbl/year.
In a national emergency, it seems to me that rationing of domestic and Canadian production would be far more important than the SPR.
The Arguello Inc. Harvest Oil Platform off the coast of California.
---quoted from Haines, B. et al. (2007).
This is about half a day of world production/consumption of 29 Gbl/year circa year circa 2005 (Wikipedia: World oil production). See also Energy Resources and Consumption: Oil.
0.044 Gbl 365.25 days
------ * ------------- = approx 0.5 days .
29 Gbl/year 1 year
If I recall correctly, James Bond, in
Diamonds are Forever visits an ocean platform off California---but
that was long ago in 1971.
Credit: An employee of NASA. As a work of the U.S. federal government, the image is in the public domain.
Download site: NASA-JPL: Ocean Surface Topography from Space.
Time zero for an R/P ratio is usually NOW.
So R/P is the time from now to exhaustion of the reserve---if the assmptions hold.
Proof:
Let t be the current time measured from a reference time zero.
R_0 be the reserve at the reference time zero.
P be the constant production rate
R be the current reserve.
Note that R = R_0 - Pt
Now the time of exhaustion as measured from the
reference time is
t_exhaustion = t + R/P
= t + (R_0-Pt)/P
= t + R_0 - t
= R_0
which is a constant.
In reality, the reserve R for many non-renewable resources can only be estimated.
This is because we don't have NATURE'S complete inventory.
And also what is considered a reserve (or recoverable reserve or proved recoverable reserve) changes with technology and price.
And, of course, P is usually far from constant.
As a resource tends toward exhaustion, the production (consumption) rate tends to fall which delays the the exhaustion.
So the R/P ratio at best is an estimate of time to reserve exhaustion.
And at worst, it is wildly inaccurate.
In that case, the R/P ratio would be
t = R/P = 1300/3 = 430 years
We shouldn't be burning our plastics
raw material.
For another example, I think I've read, but cannot now find, that the oil R/P ratio has been about 40 years for about 40 years---this may be just an incredible factoid.
If the predicted exhaustion 40 years had been an valid forecast, we would have no oil today.
But, in fact, the oil R/P ratio is still 40 years.
Used with caution, the R/P ratio it is a meaningful parameter:
---Ebenezer Scrooge's question to the Spirit of Christmas Yet to Come in A Christmas Carol, Stave III (Charles Dickens).
Caption: "Ignorance and Want, woodcut from A Christmas Carol by Charles Dickens (1812 - 1870)" (2008feb).
Author: John Leech (1809 - 1870).
Linked source: Wikipedia image http://en.wikipedia.org/wiki/Image:A_Christmas_Carol_-_Ignorance_and_Want.jpg.
Public domain.