chapter notes

44 views3 pages
user avatar
Published on 31 Oct 2010
Environmental Science
Chapter 15
- geothermal power from Earth’s core
- gravitational pull of the Moon and sun ocean tides
fossil fuels: highly combustible substances formed from the remains of organisms from past geologic
ages oil, coal, and natural gas
aerobic decomposition: in the presence of air, bacteria and other organisms that use oxygen to break
down plant and animal remains into simpler carbon molecules that are recycled through the ecosystem
anaerobic environment: one that has little or no oxygen bottoms of shallow seas, deep lakes, and
kerogen: an oil precursor formed through decomposition of organic matter which have accumulated at
bottoms of water bodies
+ geothermal heating to create crude oil and natural gas
- natural gas can also be produced nearer the surface by anaerobic bacterial decomposition of
organic matter
o methane and typically includes varying amounts of other volatile hydrocarbons
o ¼ of global commercial energy consumption cleaner-burning fuel less pollution
o Biogenic gas @ shallow depths by the anaerobic decomposition of organic matter by
o Thermogenic gas @ compression of organic material + heat deep underground
o Precursor materials from animal and plant matter
o Maturation as organic matter is buried deeper under sediments, the pressure exerted
by the overlying sediments grows and temperatures increase
o Coalbed methane commonly leaks into the atmosphere during mining
o Versatile and clean-burning, emitting half as much CO2/e as coal and 2/3 as oil
o Can be converted to liquids at low temperatures (liquefied natural gas)
- oil and gas resides in porous rock layers beneath dense, impervious layers
o offshore drilling
o 37% of worlds commercial energy consumption
o Forms in temperature/pressure conditions found 1.5-3km below the surface by dead
plant & animal material
o Mixture of hundreds of different types of hydrocarbon molecules characterized by
carbon chains of different lengths
o After produced, liquid migrates upward through rock pores
o Technology sets a limit on the amount that can be extracted; economics determines
how much will be extracted
o Oil already under pressure
o If pressure is already relieved, oil/natural gas becomes harder to extract and needs to be
pumped out
o Primary extraction: the initial drilling and pumping of available oil
o Secondary extraction: solvents are used/underground rocks are flushed with
water/steam to remove additional oil
o Refining process: separate its various components
- coal is formed when plant matter is compacted so tightly that there is little decomposition
o organic matter (generally woody plant material) compressed to form a dense-carbon
rich solid material
o precursor is peat (a moist soil composed of compressed organic matter)
o ¼ of the worlds commercial energy consumption
Unlock document

This preview shows page 1 of the document.
Unlock all 3 pages and 3 million more documents.

Already have an account? Log in