ENERGY
RESOURCES
Energy
Among
the most important resources of an industrial society are those that provide
energy - this is what we use to drive machines and use to produce other
materials (eg. smelting of metals).
For much
of history main source of energy (fuel) was wood (technically renewable).
Now
fuels dominated by fossil fuels (80%) with hydro (5%) nuclear (7%) renewables
(5%)
Forms of energy
Energy
is the capacity to do work, but is
present in different forms:
kinetic: motion, heat, electricity
potential(stored):
chemical, nuclear, elastic, gravitational, elecromagnetic
Can be
converted from one form to another
eg.
chemical
—> electrical (battery)
electrical
—> kinetic (electric motor) etc etc.
Rate of
consumption of energy is called power
Units of energy
Basic
unit of energy in SI (system internationale) is the joule
One joule is defined as the energy needed to raise the
temperature of one kilogram of water by
10 C)
Power is
the rate of use of energy or
energy/time
Thus, energy = power x time
Basic unit of power - the use of one joule/second is
called the watt
Other
units:
Kilowatt-hour
(kw-hr)= 1000 watts x 60x60 joules
1
kw-hr= 3.6 x 106 joules
Calorie =
4.18 joules
1
kw-hr = 8.6 x 105 calories
(note
that a diatetic calorie, the type talked about in diets is, really a
kilocalorie - that is equal to 1000 calories!)
British
thermal units (BTU)
= 252 calories
= 2.93 x 104 kw-hr = 1.053x103
joules
Quad= 1015 BTU = 1.05 x 1018 joules = 2.93 x 1011 kw-hr
For petroleum
Oil is
measures in barrels (bbl);
1barrel
= 42 gallons(US), 7.5
barrels = 1metric ton
1bbl =
5.7 x 109 joules = 1.59 x
103 kw-hr = 5.4 x 106
BTU
For
coal
1 metric
ton coal = 0.66 metric tons of oil = 5 bbl of oil
1 metric
ton coal = 2.85 x 1010 joules = 7.95 x 103 kw-hr = 2.7 x 107 BTU
Energy consumption patterns
Energy
is just like the other resources discussed - the richer
consume more than the poor. Note
that much of this is not just direct consumption, but is the energy invested in
the manufacture of articles.
US with
about 5% of world population consumes about 33% energy.
MDC's
addiction to energy resources has been a major source of political tension (see
Daniel Yerkin's "The Prize") and changed patterns of exploration and
production
Demand
quadrupled between 1943 and 1973, grown a further 35% since then.
Energy
flow in the US - see fig 5.2 in text
Fossil Fuels – Coal
First of
the fossil fuels – drove the industrial revolution
Known
since ancient times, but only really important since 18th
century. Abraham Darby, 1710, used
to smelt iron. Later use spread
across Europe. Use
aided by transportation, first canals and later railroads.
First
coal production in Virginia (1750) and Pennsylvania (1759) – may have
saved the eastern states forests!!
Formation
of Coal
All coal
some type of carbon compound or pure carbon formed from fossilized plant
material. Will only be formed when
the plant growth is abundant and when environment conditions will result in rapid
burial.
Higher
plants (needed to form humic coals) did not evolve until Devonian (400 Ma) so
no large coal deposits rocks
formed before that time.
Most
coals formed in tropical, swampy areas. River delta’s ideal because also
carry sediment to bury accumulated vegetation.
Coalification
As
vegetation-rich layers are buried under sediments, pressure and increasing
temperature change the nature of the material
vegetation
-> peat -> lignite (brown
coal) -> bituminous -> anthracite
[low rank] [high
rank]
At each
stage volatiles lost, so is a consequent increase in carbon content. Thus high
rank coals provide more energy.
Layers of coal called seams.
Distribution
of coal in space and time
Fig
5.11, 5.15 and 5.16 in text
Extraction
of Coal
Originally
very labor intensive, mainly underground mining, but helped by fact that occurs in layers. In early years
many horrors including child labor, 60 hour work weeks etc. (see Emile
Zola’s “Germinal” for account of coal mining in late 19th
France). Also very
dangerous. Cave-ins, explosions (due to methane gas a.k.a “fire
damp” etc. Made mining
hotbed of union activity.
In late
20th century much mechanization.
Coal
cutting machines
Surface
mining of coal
– Tertiary age coal of western states.
Economic
if stripping ratio does not exceed 20:1
Use
of coal
Nowadays
most coal is burnt at powers stations to make electricity.
Some
converted to coke for use in metals smelting.
Environmental
problems of coal production and
burning
Acid
mine drainage
Subsidence
Slag
(spoil) heaps
Acid
rain
Global
Warming
Fossil Fuels – petroleum and gas
(hydrocarbons)
Natural
seeps of petroleum occur providing source of hydrocarbons since antiquity.
Bitumen(tar
or pitch) main product in ancient world (many biblical references for example).
Moors in 1st century CE distilled kerosene, but discovery was
forgotten and not used until 19th century. “Coal oil” distilled and used instead of whale
oil in lamps.
Edwin
Drake drilled first well in Titusville Pennsylvania, 1859. Spread rapidly thereafter. Main interest was for lighting
and lubrication.
Invention
of internal combustion engine (late 19th-early 20th
centuries) spurred more demand.
World war I expanded these markets greatly
Even
greater expansion after World War
II
Formation
of hydrocarbons (petroleum and natural gas)
natural
gas: mainly methane
(CH4)
ethane
(C2H6)
propane(C3H8)
butane(C4H10)
produced
by breakdown of organic matter.
Sulfur,
nitrogen often present, also
Organic matter
in question is from marine plankton (mainly phytoplankton, but some
zooplankton) that are abundant on
continental shelves. As these sediments are buried temperature rises and
organic products break down. Three
stages developed
Diagenesis
< 500C , few hundred meters depth; “heavy”
oil
Catagenesis 50-1500C up to 5000 meters – kerogen and
“light” petroleum
Metagenesis
>1500C gas
4-5000 meters
Individual
histories result in individual characters of oils from different oil fields
These
materials developed in source rocks ie those
which contained the micro-organisms. Usually mudstones or siltstones.
Oil/gas
escapes and becomes lodges in a reservoir – body of porous and permeable rock. To remain there a cap rock and trap structure are needed.
Distribution
of hydrocarbons in space and time
Age
distribution in rocks
Global
distribution
Exploration
for hydrocarbons
1 . Obtain exploration concession
2.
Geologic investigation to see if right kinds of rocks
3.
Geophysical investigations – seismology to see if trap structures exist
4.
Exploratory drilling – see if hydrocarbons really there. [Random drilling known as wild-catting.]
5.
Assessment of reserves
Reservoir
volume = R
Reservoir
porosity = V
Recovery
factor = R
Volume
of recoverable hydrocarbons = VxPxR
Huge
investment before any production can even begin.
Extraction
of hydrocarbons
By
drilling. Various types of
drilling. Rotary drills.
Marine
drilling
Problem
of gas pressure. Blowouts and
“gushers. Blowout preventers.
Enhanced
recovery – flooding (water +chemical), steam, CO2 injection
Refining
Not just
petroleum produced. Many products
Where are world’s oil reserves?
Largest amount in middle Asia, Arabia and Africa
Dominated by the cartel Organization of Petroleum
Exporting Countries (OPEC)
OPEC’s role
Oil
consumption and future of oil
1859-mid
1970’s, US dominated production.
Peak of production 1970, since then declining steadiliy - more reliance
on imported oil. Rest of the
world also using more oil. At
present US consumption 3% of world’s
Future
of oil globally – cumulate consumption curve
However
since petroleum not evenly distributed throughout world, so in future more
reliance on OPEC producers.
Natural
Gas
Gas
originally udes for lighting.
Distilled from coal.
1802-4 “coal” gas used to light factories
Late 19th
centrury important for public lighting – street lamps . Mantled lamps and
“limelight”
Natural
gas pioneered in eastern US.
Transported in wooden pipelines!
Again main use was lighting – almost killed by invention of
electric light.
Problem
of natural gas was always difficulty of transportation.
Later 20th
C improvements in technology:
pipeline technology, liquefaction (chilling and compression to 1/600th
of gaseous volume) to produce LNG.
Also gas can be stored in old oil fields when demand is low
Attraction:
no refining, clean burning, more heat per weight than any other fossil
fuel
Reserves
US well
endowed
Russia
and ex-soviet states have most
Total
reserves unknown, but energy content at least equal to petroleum and
geographically more diverse.
Other
hydrocarbon resources
Tar
sands: - essentially heavy oil trapped in
reservoir rocks
Oil
shales –
essentially source rocks from which oil has not migrated
Energy consumption patterns
Energy
is just like the other resources discussed - the richer
consume more than the poor. Note
that much of this is not just direct consumption, but is the energy invested in
the manufacture of articles.
US with
about 5% of world population consumes about 33% energy.
MDC's
addiction to energy resources has been a major source of political tension (see
Daniel Yerkin's "The Prize") and changed patterns of exploration and
production
Demand
quadrupled between 1943 and 1973, grown a further 35% since then.
1950's
and 1960's
1957
Suez Canal crisis staunched the flow of Middle Eastern Oil
led to
search for new fields in Africa (Nigeria, Libya, Algeria, Alaska) - extra
production caused oil prices to fall
1967
development of supertankers ( >160,000 tons) led to drop in price of oil
(Iranian oil landed in Europe and US for little more than the wellhead price in
US Canada), domestic production ran down in face of Cheap imports
1970's
1973
Middle Eastern Crisis, OPEC (dominated by Muslim states) blocked export of oil
to US and its allies in political protest against US support of Israel. Only
then were brakes imposed. Switch from oil to natural gas for heating. Coal
demand increased. For two years oil demand fell
1979-80
Shah of Iran deposed, Iran Iraq war caused problems, gas prices rise
($13—>$34). Total energy demand fell.
Public
concern about nuclear power causes halt in constuction of nuclear power
stations
1980's
and early 90's
Demand
in 1983 rises, mainly due to industrialization of Latin America and SE Asia.
OPEC
overproduction, opening of North Sea and Alaska, causes stagnation in petroleum
prices, Domestic production declines in favor of cheap imports. New extraction
technologies increase oil; field output, so exploration foe.
1992
Gulf War because of invasion of
Kuwait, but quick resolution ensured supplies not significantly interrupted.
But what
of the future????
Consumption
has not halted. Possibility of
more political instability, inrceased consumption in developing as well as
developed nations may cause increasing problems.
Return
to these problems after examining energy sources.
FLORIDA INTERNATIONAL UNIVERSITY
State University System of
Florida
Department of Earth Science s
GEO
3510 Earth Resources
energy Units
Basic
unit of energy in SI (system internationale) is the joule
One joule is defined as the energy needed to raise the
temperature of one kilogram of water by
10 C)
Power is
the rate of use of energy or energy/time
Thus, energy = power x time
Basic unit of power - the use of one joule/second is
called the watt
Other
units:
Kilowatt-hour
(kw-hr)= 1000 watts x 60x60 joules
1
kw-hr= 3.6 x 106 joules
Calorie =
4.18 joules
1
kw-hr = 8.6 x 105 calories
(note
that a dietetic calorie, the type talked about in diets, is really a
kilocalorie - that is equal to 1000 calories!)
British
thermal units (BTU)
= 252 calories
= 2.93 x 104 kw-hr = 1.053x103
joules
Quad= 1015 BTU = 1.05 x 1018 joules = 2.93 x 1011 kw-hr
For
petroleum
Oil is
measures in barrels (bbl);
1barrel
= 42 gallons(US), 7.5
barrels = 1metric ton
1bbl =
5.7 x 109 joules = 1.59 x
103 kw-hr = 5.4 x 106 BTU
For
coal
1 metric
ton coal = 0.66 metric tons of oil = 5 bbl of oil
1 metric
ton coal = 2.85 x 1010 joules = 7.95 x 103 kw-hr = 2.7 x 107 BTU