Fossil Fuels Flashcards
what are some potential alternative energy sources to fossil fuels
- geothermal energy from earth’s core
- energy from gravitational pull of moon and sun
- energy from ocean tides
- nuclear power
where does most of our energy come from
sun
why is solar radiation important
helps drive atmospheric winds and hydrologic cycle which makes wind and hydroelectric power possible
fossil fuels
Highly combustible substances formed from the remains of organisms from past geological ages
what are the main fossil fuels
- oil
- natural gas
- coal
since when has fossil fuels been the dominant source of fuel and WHAT did it replace at the time
- industrial revolution
- replaced biomass (fuelwood)
has the consumption of fossil fuels risen or fallen over the years
risen - reaches the highest levels ever NOW
renewable energy
sources of energy that are NOT depleted by our use
non-renewable energy
sources of energy that CANNOT be regenerated quickly enough to offset depletion
examples of renewable and non-renewable energy sources
renewable
- sunlight
- geothermal energy
- tidal energy
non-renewable
- oil
- coal
- natural gas
- nuclear power
compare the energy consumption in developing and developed nations
developing nations
- consume LESS energy
- more energy devoted to agriculture, food preparation and heating and LESS energy devoted to transportation
- rely more on manual or animal sources
developed nations
- consume MORE energy
- 1/3 used on transportation
- 1/3 on industry
- 1/3 on all other uses
- rely more on automated energy sources
does making energy take energy
YES - To harness, extract, process and deliver energy it requires substantial inputs of energy
net energy
the difference between energy RETURNED (consumable energy) and energy INVESTED to acquire it
(net energy = energy returned-energy invested)
EROI (Energy Returned On Investment) equation
usable energy returned / energy invested
what do higher EROI ratios show
acquire more usable energy from each unit of energy that was invested
what do EROI ratios of 1 mean
energy invested is the SAME as the energy acquired
why are fossil fuels so widely used
because they have a HIGH EROI ratio
what are fossil fuels used today formed from
tissues of organisms that lived 100 million to 500 million years ago
hydrocarbon compounds
Organic molecules dominated by hydrogen and carbon
Aerobic decomposition
Bacteria and other organisms that use oxygen break down plant and animal remains into simpler carbon-based molecules
do fossil fuels result from aerobic or anaerobic environment
ONLY anaerobic environment (environments with little to no oxygen)
Kerogen
Oil precursor that results from the accumulation of organic matter at the bottom of water bodies that undergo decomposition and deep burial by sediment
how do fossil fuels form
when geothermal heating acts on the kerogen and alters both chemically and physically
what four traits determine the specific type of fossil fuel formed
a) Chemical composition of starting organic material
b) Temp and pressure material is subjected to
c) Presence of absence of anaerobic decomposers
d) Passage of time
what type of rock forms coal
sedimentary deposits found in terrestrial wetlands and shallow lakes
what type of rock forms oil and natural gas
rock formed from shallow marine sedimentary deposits (limestone)
what is coal
organic matter from WOODY PLANTS that was compressed under very high pressure to form dense, combustible and carbon-rich solid material
what fossil fuel has been used the longest
coal
what is the precursor to coal
peat
(Moist soil composed of anaerobically broken down organic matter)
how does peat turn into coal
peat is subjected to increasing pressures and temperatures which causes
a) thickness and moisture to decreases
b) Hardness increase
c) Colour changes from brown to glossy black
what are the locations where coal is found called
coal seams
what are the three grades of coal
a) lignite - lowest and softest grade of coal - least compressed
b) sub-bituminous and bituminous coal - produce steam for electricity
c) anthracite - highest grade - most compressed - has most energy
what are two major mining methods for coal
Subsurface mining for deep deposits
Surface mining for shallower deposits
§ Open pit mining
§ Strip mining
describe subsurface mining for coal
○ Shafts are dug deep into the ground
○ Networks of tunnels are dug or blasted out to follow the coal seams
compare the two types of surface mining methods for coal
a) open-pit mining
- Large excavations which are deepened and widened as mining proceeds
b) strip mining
- Heavy machinery removes earth in long, horizontal strips to expose the seams and extract coal
- Refilled with soil that has been removed
Negative impacts of coal mining on ecosystems
- strip mining destroys large ranges of habitats
- causes soil erosion
- chemical runoff into waterways through acid drainage
what are two pathways for clean coal technologies
Cleaner combustion
- Provide improvements aimed at making combustion more efficient and complete = cleaner
Gasification
- Creating clean synthetic fuels (syngas) from mixtures of crushed coal, methane, water vapor and other components
because gasifying or liquefying coal makes it burn cleaner and renders it more useful
natural gas is primarily
mainly methane with varying amounts of other volatile hydrocarbons
what fossil fuels provides 1/4 of total global commercial energy consumption
natural gas
is natural gas cleaner than burning oil or coal
yes as it produces less pollution
why is natural gas becoming more widely favoured as a fossil fuel
○ Easy to transport
○ Technologically versatile
○ Relatively clean burning
* Shipped long distances when converted to liquid natural gas (LNG)
what are two ways to form natural gas
Biogenic gas
- created at shallow depths by anaerobic decomposition of organic matter by bacteria
- is generally PURE methane
Thermogenic gas
- Compression of organic material along with heating deep underground
- Contains small amounts of other gases
describe the maturation process in natural gas formation
§ Carbon bonds in organic matter break and organic matter turns into kerogen
§ Further heat and pressure on kerogen = degrade complex organic molecules into simpler hydrocarbons
why does natural gas often go to waste when extracted
as it escapes during extraction of coal and oil
(known as coalbed methane)
what is the main process for removing natural gas from the ground
○ Fracturing technique involving pumping a fluid (water) under high pressure into the rocks to crack them
○ Sand or small glass beads are then injected to hold the cracks open once the water is withdrawn (proppants)
what are some environmental impacts from fracking
○ Water-intensity of the process
○ Earthquakes caused by rock cracking
○ Additives to change the viscosity of the natural gas can escape and contaminate water supplies
what is the world’s most used fuel
oil
what is the most ABUNDANT fossil fuel
coal
what are synonyms to oil
- crude oil
- petroleum
how is oil produced
A fossil fuel produced by conversion of dead organic materials by heat and pressure that have been buried in MARINE SEDIMENTS
what is oil (describe it’s structure)
A mixture of different types of hydrocarbon molecules characterized by carbon chains of different lengths
why does the formation of oil have to take place in a specific range of depth (1.5 to 3 km deep)
a) At lower temps and pressures the organic matter would remain as kerogen
b) At higher temps and pressure natural gas might form instead of oil
what are the principle conditions when oil is formed
Once formed, crude oil moves upward from its source rock and escapes into atmosphere however if prevented from moving upwards by impermeable layer of rock (cap rock) the oil collects in reservoir rocks
determine the roles of economics and technology in the extraction of oil
Technology sets a limit on the amount of oil that CAN be extracted
economics determines how much WILL be extracted
steps of the extraction of oil
exploratory drilling
- small, deep holes that are drilled prior to full scale extraction to see if the area is plentiful or not
Primary extraction
- Initial extraction of oil from the well
- Once the initial pressure is relieved the oil and natural gas become more difficult to extract and usually must be pumped out with increasing pressure
Secondary extraction
- Fluids are injected into the grounds to remove additional oil that could not be removed with primary extraction
is secondary extraction of oil more or less expensive than primary extraction
more
what stage of oil extraction has MORE of an impact on the environment
secondary extraction
why does oil have different lengths of hydrocarbon chains
affects it chemical properties
(Different lengths of the chains dictate what the crude oil will be used for (gasoline for engines, tar and asphalt)
what is refining in terms of oil production
Hydrocarbons are separated into classes of different sizes and chemically transformed to create fuels for heating, cooking, transportation and lubricating oils, asphalts…
distillation of oil
- Based on how different components of crude oil boil at different temps (colder boiling points at the top and hotter boiling points at the bottom)
i. lighter components rise as vapour to upper trays where they condense into liquids as they cool
ii. Heavier components sink to the lower trays
Three types of unconventional fossil fuels
- Oil sands (tar sands)
- Shale oil and gas
- Methane hydrates
oil sands
Deposits of moist sand and clay that contain concentrations of heavy hydrocarbons more specifically BITUMEN
(Thick, black and naturally occurring form of petroleum that is rich in carbon but poor in hydrogen )
what are some issues associated with bitumen in oil sand production
a) Bitumen is too thick to be extracted in conventional oil drilling methods (removed by strip mining)
b)Bitumen is too thick to transport by pipelines that are used to carry crude oil
oil shale
A sedimentary rock that contains abundant kerogen
how is the maturation process of oil shale different from crude oil OR oil sands
Formed by same maturation processes that form crude oil and oil sands but kerogen is NOT buried deeply enough (or subjected to enough heat) to fully mature into oil
what is shale gas
Natural gas produced from shale by fracking
Methane hydrate
A solid substance that consists of molecules of methane within a crystal lattice of water ice molecules
Environmental impacts of alternative fossil fuels
a) Net energy values for these fuels are typically low since they are expensive to extract and process
b) pollute waterways and devastate landscape
c) Combustion of these fossil fuels emits at least as much carbon dioxide, and other air pollutants as fossil fuels
Negatives of fossil fuels
- Cause air pollution and drive climate change
- Burning fossil fuels alters flux rates in carbon cycle
- Methane is released from fossil fuel combustion (another GHG)
- runoff contaminates waterways and freshwater ecosystems
Impacts on terrestrial and aquatic environments of fossil fuels
- Fossil fuels can pollute water and land and air
- Oil from non-point sources eventually enters the ocean
- Oil spills affect marine environments
Energy conservation
The practice of reducing energy use to extend the lifetime of our non-renewable energy supplies, to be less wasteful and to reduce environmental impacts
what are routes for energy conservation
a) Personal choice
(Make conscious choices to reduce our own energy consumption)
b) Increased efficiency
(2/3 of energy from fossil fuels is lost, as waste heat)
electricity
secondary form of energy (aside from fossil fuels) that is easier to transfer and apply to a number of uses (when compared to fossil fuels)
nonrenewable energy sources
- crude oil
- natural gas
- coal
- nuclear energy
renewable energy sources
- biomass energy
- hydropower
- wind energy
- solar energy
- tidal and wave energy
what are Canada’s 3 BIGGEST sources of energy consumption
- oil (31%)
- natural gas (28%)
- hydroelectric power (27%)
when does the EROI ratio begin to DECLINE
when we extract the easiest deposits to reach FIRST and then we are left with harder deposits to extract which means we have to input MORE energy to extract the reserves
Fossil fuels
combustible substances that have formed from remains of past organisms of previous geologic ages
what are the three fossil fuels that are formed from the organic matter
natural gas
crude oil
coal
what factors determines how long a nation’s reserves will last
a) how much the nation extracts (consumes)
b) how much it IMPORTS from OTHER nations (means the country relies on others for these resources)
c) how much it EXPORTS to other countries
what nation has the most coal reserve of any other nation
USA
3 different types of recoverable oil
a) technically recoverable oil
- oil that is able to be extracted with the current technology available
b) economically recoverable oil
- balance between cost of extraction, transportation and current price of oil
c) proven recoverable reserve
- oil that is technologically and economically feasible to remove
R/P ratio for OIL
reserves to production ratio
(total remaining reserves / the annual rate of production)
how many years do we have for each fossil fuel
coal - about 120 years
natural gas - about 60 years
crude oil - about 40 years
how can bitumen from oil sands be transported easier
when converted to dilbit as it decreases the thickness of the oil and allows it to flow through a pipeline
describe the EROI of alternative fossil fuel options
LOW energy return on energy invested
what is carbon capture and storage
liquefied carbon dioxide is pumped into underground aquifers or depleted oil and gas deposits to possibly reduce harmful environmental impacts of fossil fuel use
why are people skeptical of CCS
- the tech is unproven
- the true impacts of this are not completely known
- it will increase acidification of ocean water/ground water
