XV - Nonrenewable Energy Resources Flashcards
Commercial energy in less developed countries
41% renewable
59% nonrenewable
Commercial energy in more developed countries
10% renewable
90% nonrenewable
Renewable energy sources
Biomass
Hydropower
Geothermal power
Solar power
Nonrenewable energy sources
Nuclear power
Natural gas
Coal
Oil
Energy consumption in the US
Largest user/waster of commercial energy
84% fossil fuel
7% nuclear energy
9% renewable
Energy consumption shift in the US
Since the early 1800s, the sources of commercial
energy used in the United States have shifted from
wood to coal to a mix of oil, coal, natural gas, & nuclear
Evaluating Energy Resources
Available energy source Cost Env'tal impact Net energy yield Sustainability
Net energy
the total useful energy available from a
resource over its lifetime minus the amount of energy
used, automatically wasted, & unnecessarily wasted to
find, process, & transport it
Net energy ratio
ratio of useful energy
produced to the useful energy used to produce it;
the higher the ratio the greater the net energy yield
Net energy ratios for space heating
passive solar 5.8 Natural gas 4.9 oil 4.5 Active solar 1.9 coal gasification 1.5
Petroleum or
crude oil
complex liquid mixture of hydrocarbons, with small amounts of sulfur, oxygen, & nitrogen impurities produced by the decomposition of deeply buried organic matter from plants & animals (fossil fuel)
Where is crude oil generally found?
In sedimentary rock layers with oil dispersed in pores and cracks of rock formation
Primary oil recovery
drilling a well &
pumping oil that flows by gravity into the bottom of
the well
Secondary oil recovery
injecting water in
nearby wells to force remaining heavy oil to the
surface
Tertiary or Enhanced Oil Recovery
using steam or CO2 gas to force still more oil into the well
Refining of crude oil involves
separating components based
on their
boiling point
Gasoline & aviation fuel
most volatile components
Heating oil
less volatile, but still
burns readily
Diesel oil
less volatile, and is a
common fuel for trucks, buses, &
heavy machinery
Grease, wax, & asphalt
the least
volatile, most dense materials
separated
Petrochemicals
derived from oil are used for synthesizing industrial organic chemicals, pesticides, plastics, synthetic fibers, paints, medicines, & many other products.
Thirteen countries that make up the Organization of Petroleum Exporting Countries (OPEC) have 67%
of the world’s reserves of oil
Algeria, Ecuador, Gabon, Indonesia,
Iran, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia,
United Arab Emirates, & Venezuela
Oil in the US
U.S. has only
2.3% of the world’s oil
reserves, but uses
nearly 30% of the oil
What is oil mainly used for in the US?
65% of oil in the U.S.
is used for
transportation
Why does the US import oil?
Little new oil & natural
gas are expected to
be found in the U.S.
Crude oil prices
When the price is adjusted for inflation, oil has remained cheap since 1975
How Long Will Oil Supplies Last?
Oil supplies will be 80% depleted within 35–84
years, depending on the consumption rate
Synthetic crude oil
produced from oil shale (involving grinding large
quantities of rock) or from tar sand (shown below)
Characteristics of synthetic crude oil
quality is
lower, environmental impact higher, & energy yield lower than for oil from
conventional sources.
Pros of oil
• Oil is still cheap;
• Economy is set up around use of oil;
• Many useful products can be readily synthesized from
oil
Cons of oil
• Supply is limited & will be depleted within 35–84
years;
• Pollution & environmental degradation result from
extraction, processing, transport, & use
Conventional natural gas
trapped above oil
deposits
Unconventional
natural gas
found in coal
beds, tight sands,
& dissolved in
deep hot water.
Natural gas
fossil fuel, produced by
decomposition of deeply buried organic matter
from plants & animals
Liquefied petroleum gas
propane & butane gases removed from natural gas
Characteristics of natural gas
Natural gas is a mixture of 50–90% methane (CH4), with
smaller amounts of ethane (C2H6), propane (C3H8), &
butane (C4H10), and the toxic gas hydrogen sulfide (H2S)
typically transported in pipelines from oil fields to users
Natural gas sources
Russia and Kazakhstan have almost 40% of the
world’s natural gas supply
Other countries with large reserves: Iran (15%),
Qatar (5%), Saudi Arabia (4%), Algeria (4%), United
States (3%), Nigeria (3%), Venezuela (3%)
Natural gas sources in US
90–95% of natural gas used in the U.S. is domestic & the remaining 5–10% is from Canada (estimated
411,00 km = 255,00 miles of pipeline).
Pros of Natural Gas
• cheaper than oil;
• reserves are more abundant than oil: 65–80 years for
U.S., 125 years for world at current consumption
rates;
• easy to transport over land by pipeline;
• burns hotter, cleaner, & produces less carbon dioxide
than other fossil fuels
Cons of Natural Gas
• transport overseas requires conversion to liquid
natural gas (LNG), pressurized & highly flammable;
• pollution & environmental degradation result from
extraction, processing, transport, & use (though less
than other fossil fuels)
Coal is composed of …
mostly carbon, with smaller amounts of water, sulfur &
trace amounts of radioactive
materials
Coal is typically extracted by
strip mining or
underground
coal mining
Coal
fossil fuel, produced from the buried remains of
swamp plants that died during the Carboniferous period (geologic era ending 286 million years ago)
Stages in coal formation
Peat
Lignite
Bituminous Coal
Anthracite Coal
Peat
Not a coal
Partially decayed plant matter in swamps & bods
Low heat content
Lignite
Brown coal
Low heat content
Low sulfur content
Limited supplies in most areas
Bituminous coal
Soft coal
Extensively used as fuel due to high heat content & large supplies
High sulfur content
Anthracite
Hard coal
Highly desirable fuel because high heat content & low sulfur content
Supplies are limited
Coal sources
About 66% of the world’s proven coal reserves and
85% of the estimated undiscovered deposits are in the United States, the former Soviet Union, and China.
What percentage of commercial electricity is based on coal?
Coal provides about 25% of the world’s commercial
electricity (22% in U.S.)
What percentage of global electricity is generated by goal?
Used to generate 64% of world’s electricity (57% in
U.S.)
Synfuels
Coal can be converted into gaseous & liquid fuels
Low net energy yield
Coal pros
• most abundant fossil fuel;
• U.S. has major reserves, will last 300 years at current
consumption rates;
• high net energy yield
Coal cons
• dirtiest fossil fuel, in terms of air pollution & carbon
dioxide released;
• major environmental degradation that result from
extraction, processing, transport, & use;
• burning coal is major threat to human health ––
estimated to kill or cause chronic respiratory disease
for large numbers of people.
Nuclear fission
nuclear change in which certain
unstable isotopes of high mass numbers split into lighter
nuclei & release energy in the process
Nuclear fission reactors
produce electricity from
heat released by the fission of atoms such as
uranium–235 & plutonium–239
Nuclear chain reaction
multiple fissions resulting from
a positive feedback loop in which each fission releases
neutrons that cause more fissions to occur
Controlled fission steps
I - bringing fissionable atoms to critical mass
II - converting enriched uranium into fuel pellets which are then stacked into fuel rods, grouped into fuel assemblies, and lowered into reactor
III - controlling rate of fission by absorbing excess neutrons with control rods & surrounding the reaction core with coolant
Number 2 Three Mile island explosion (1979)
near Harrisburg, PA
• 50,000 people evacuated & another 50,000 fled area;
• unknown amounts of radioactive materials were
released;
• partial cleanup & payment of damage claims cost $1.2
billion so far;
• 1997 concluded that increased cancer rates were
caused by released radiation
Ukraine Chernobyl explosion (1986)
•In 1998 the Ukrainian health ministry reported 3,576
deaths. However, Greenpeace estimates a total
death toll of about 32,000;
•about 400,000 people were forced to leave their
homes;
•according to a UN report, some 160,000 sq
kilometers (62,00 sq miles) remain contaminated;
•over half a million people were exposed to dangerous
levels of radioactivity;
•the cost of the incident is estimated in excess of $358
billion.
Nuclear Energy use in the US
Eventually phasing out
• U.S. currently only gets about 7% of energy from
nuclear power;
• no new power plants ordered since 1978; of 105
commercial nuclear power plants in U.S., 40%
expected to be retired by 2015 & all by 2030
Nuclear Energy use in France
• France gets about 78% of its energy from nuclear
power plants, & views nuclear energy as essential for their future
What contributed to the phasing out of nuclear energy?
• crippled by high & uncertain construction & operating
costs, billion dollar overruns;
• frequent malfunctions;
• false assurances and cover–ups by government &
industry officials;
• overproduction of energy in some areas;
• poor management;
• lack of public acceptance
Nuclear power pros
- U.S. has major reserves of uranium;
- lower mining impacts than coal;
- no carbon dioxide emission;
- no air pollution/acid-forming emissions;
- lower quantity of solid wastes
Nuclear power cons
• cost high & recently rising;
• possible major release of radioactive contaminants;
• mining & processing impacts;
• radioactive wastes: short–term containment of short–lived
isotopes (now water–filled tanks); transport & long–term
containment of long–lived isotopes;
• thermal pollution
