Chapter 15: energy Flashcards
What is the mackenzie valley gas project?
a proposal to develop three major gas fields in the mackenzie delta, NWT.
examples of fossil fuels?
oil , natural gas, coal, oil shale, tar sands
what are fuels?
energy stored in chemical bonds of ancient organic life.
What is electricity?
A secondary form of energy that is easier to transfer than fossil fuels
When are fossil fuels produced?
when organic materials are broken down in anearobic(little to no oxygen) environments. occurs at the bottom of deep lakes, swamps, and shallow seas
what nation has the most coal?
USA
Net energy =
Energy returned - energy invested
what is coal?
organic plant and animal matter that was compressed under very high pressure to form dense carbon structures
What is the least compressed and most compressed (more energy) coals called?
Lignite LLLeast compressed
Anthracite most compressed
how does peat differ from coal?
peat remains wet when broken down, not well compressed
What impurities does coal contain
sulfur, mercury, arsenic, and other tracd materials.
What does the sulfur content of coal depend on?
whether it was formed in saltwater or fresh water
what are oil and natural gas mainly formed from?
plankton, including algae and bacteria
What does natural gas consist of?
Methane(ch4), varying amounts of other volatile hydrocarbons
How much of the worlds energy is from natural gases?
25%
How much longer are the worlds natural gases expected to last for?
only 60 yrs
What is kerogen?
A precursor to oil, created at shallow depths by bacterial anearobic decomposition of organic matter
What is coalbed methane
methane from coal seams, leaks to atmosphere during mining
What is crude oil?
A mixture of hundreds of different types of hydrocarbon molecules. Formed 1.5-3 km underground from dead organic material buried in marine sediments
whats the mosr abundant fossil fuel?
coal
what is the precursor to coal?
peat
subsurface mining
Involves digging deep into the ground, and networks of tunnels are dug or blasted out to follow coal seams
strip mining
heavy machinery removes earth in long, horizontal strips to expose seams and extract coal. pits are refilled with the soil that was removed.
Acid drainage
when sulfide minerals in newly exposed rock surfaces react with oxygen and rain water to produce sulphuric acid. The acid runs off and leaches toxic metals from the rocks.
Why is strip mining harmful?
- health hazards for miners
- acid drainage which affects terrestrial and aquatic ecosystems
What is a turbine?
a rotating device that converts the kinetic energy of a moving substance, such as steam, into mechanical energy
What do clean coal technologies do?
focus on ridding the toxic chemicals of coal
when is natural “gas” a liquid?
at ambient pressures and temperature in subsurface reservoirs
what is technically recoverable oil?
oil that can be extracted with current technology
what are procen recoverable reserves
oil that is technologically and economically feasible to remove under current conditions
What is secondary extraction of oil?
when solvents or water is used to remove additional oil after primary extraction, can be expensive
exploratory drilling
the drilling of small deep holes to determine where extraction of oil should be done
What is fracking(hydraulic fracturing)?
pumping fluid under high pressures into rocks to crack them and extract natural gas, can cause earth quakes
Hubberts peak
predicted that US oil production would peak around 1970, accurate
What are oil sands/tar sands?
Sand with deposits of 1-2% of bitumen, which is a thick form of carbon rich petroleum. Removed through strip mining.
What is oil shale?
Sedimentary rock filled with kerogen that can be processed to make liquid petroleum.
what is methane hydrate/ice?
Molecules of methan in chrystal lattices of water ice molecules, occurs in arctic locations and under sea floor
What is COGENERATION
When excess heat produced during electrical generation is used to heat buildings and produce other types of power (more efficent)
