Test 4 Flashcards
Fossil fuels account for what percent of energy consumption in the U.S?
85%
Alternative/Renewable energy sources
Biomass hydroelectric wind geothermal solar
Hydrocarbons created from the natural decay of organic material
Fossil fuels
3 forms of fossil fuels
Coal
Oil (petroleum)
Natural gas
Coal is derived from what?
Plant matter
Oil comes from what?
Algal remains
Natural gas is a by-product of what?
Thermal maturation of oil and coal
Advantages of fossil fuels
- global availability
- can generate enormous amounts of energy
- existing infrastructure
- power plants can be set up anywhere
Organic matter is converted to oil by increasing pressure and temperature in what?
Source rocks
Low density oil and gas migrate toward the surface through what porous rock?
Reservoir rocks
Oil and gas is trapped beneath what impermeable type of rocks?
Cap rocks
Geologic conditions able to capture and concentrate oil and gas
Anticlines, salt domes, and stratigraphic traps
Include all deposits on Earth (known and yet to be discovered, economical and not yet economical)
Resources
Known quantity of resources that can be extracted economically by today’s standards
Reserve
World oil reserves
~60% in the Middle East
~1.5% in the U.S.
World gas reserve
~70% in Russia and Middle East
~4% in North America
Environmental impacts of oil and natural gas
- artificial structures disrupt natural ecosystems
- leaking pipelines can cause soil and water contamination
- tanker or platform spills
Technique used to extract oil or natural gas from tight formations; water, sand, and chemicals are mixed together and injected into wells at high pressures to create fractures for oil and gas to be extracted through
Hydraulic Fracturing (fracking)
Forms when partially decayed remains of plants turn into peat in response to increases in pressure and temperature
Coal
Partially decayed vegetation matter, usually forms in areas with high water content; precursor to coal
Peat
Coal ranks
Lignite -> Bituminous -> Anthracite
Forms when peat is exposed to increase pressure and temperature; immature coal; gray with high moisture and ash content; lowest energy value
Lignite
Soft coal; type most commonly used for electric generation in U.S; sedimentary origin
Bituminous
Hard coal; requires very high pressure and temperature to develop in geologic layers (metamorphic origin); highest energy value
Anthracite
- recover 90-95% of coal
- much cheaper to extract coal
- relatively safe
Surface mining (strip mining)
- recover only 40-45% of coal
- more expensive method
- extremely dangerous: collapse and explosions
Underground mining
Environmental impacts of coal mining
- visual blight (strip mining)
- land subsidence (underground mining)
- enormous amounts of waste
- acid mine drainage
Gradual or sudden sinking/settling of the Earth’s surface due to the collapse of underground mines
Land subsidence
When rainfall infiltrates into coal waste piles and reacts with pyrite in the presence of free oxygen to produce acidic, metal-rich contaminated water
Acid mine drainage (AMD)
How can you minimize the impacts of fossil fuels?
- Reclamation of strip mines
- diverting water away from waste piles
- disposal of ash and cinders in underground mines
- use air scrubbers
Devices that are used to remove some particulates and gases from exhaust stacks
Air scrubbers
Organic-rich sedimentary rock that contains significant amounts of kerogen
Oil shales
Solid mixture of organic chemical compounds from which liquid hydrocarbons can be extracted
Kerogen
Sands that contain oil that is extremely viscous
Tar sands
Contained in tar sands; dense and extremely viscous form of petroleum
Bitumen
Nuclear energy
- supplies ~7-8% of U.S. energy
- primary source is radioactive elements (uranium and thorium)
Nuclear energy involves the controlled splitting of Uranium and Thorium called…
Nuclear fission
Advantages of Nuclear Energy
- large deposits of uranium and thorium
- safety records in U.S are pretty good
- efficient energy source (higher BTU than fossil fuels)
- relatively non-polluting
- uranium mines are safer than coal mines
Environmental impacts of nuclear energy
- accidental release of radioactive material
- generation of radioactive waste
Requires U.S to store waste in deep, underground geological facilities
Nuclear Waste Policy Act
Burning of wood, agricultural waste, and even urban garbage to produce heat
Biomass
Fuels produced when living organisms convert inorganic substances into organic molecules (e.g. photosynthesis); matter can be converted into gasoline substitutes
Biofuels
Damming of a river in order to use incoming water to turn turbines and generate electricity
Hydroelectric energy
Amount of energy produced by a dam is due to this volume and height difference between the source and the outflow
Hydraulic head
Wind turbines convert kinetic energy of blowing winds to mechanical energy
Wind energy
Use of heat left over from the formation of the planet and from decay of radioactive elements
Geothermal energy
Temperature difference between the Earth’s core and crust
Geothermal gradient
Use of photovoltaic panels to directly convert sunlight into electricity
Active solar technique
Selecting material with favorable thermal properties; mainly used for heat
Passive solar technique
Disadvantage of Renewable Energy
- higher costs
- impacts from mining for materials
- habitat destruction
- land degradation
- pollution concerns
Natural compounds composed of one or more elements
Minerals
Mineral characteristics
1) naturally occurring
2) inorganic
3) specific chemical composition
4) crystalline structure
Mineral groups
- silicates
- native elements
- carbonates
- oxides
- hydroxides
- sulfides
- sulfates
Metal mineral resources
- Ferrous versus non-ferrous metals
- precious metals
Non-metal mineral resources
- building materials
- industrial uses
- agricultural uses
When mineral resources become concentrated/enriched to be economical
Ore
Concentration of given mineral in ore (%) / average concentration of the mineral in crust (%)
Concentration factor
8 elements in crust
Oxygen Silicon Aluminum Iron Calcium Sodium Potassium Magnesium
Dealing with limited availability
1) find more
2) find a substitute
3) conserve and increase efficiency
4) recycle
5) do without
Created from the heating of water or other fluids by magma bodies
Hydrothermal mineral deposits
Divergent boundaries in the middle of the ocean
Mid-oceanic ridges
As magma body cools in the subsurface, individual minerals precipitate out at different temperatures; creates layered surface
Igneous mineral deposits
Mining waste
1200 active mining sites in U.S generate ~1.5 billion tons of waste annually
Materials left over after process of separating valuable portion of an ore from the uneconomic portion
Tailings
Filling in open pits, conturing land surface, replanting vegetation, and treating waste is all part of what?
Reclamation
Energy Types
Fossil fuels, nuclear energy, alternative/renewable energy sources
Emission of Sulfur dioxide (SO2) and nitrous oxides (NOx) into the atmosphere can cause this when combined with water
Acid rain
