energy non renewable-and_climate_change_
TRANSCRIPT
• Almost ALL energy ultimately comes from the sun, either directly or indirectly
Carbon cycle
Fig 15.3—Fossil fuel formation
Alberta tar sands
Fig 15.10—Alberta tar sands
Keystone XL pipeline
Petroleum/Crude Oil
• Oil in mud or clay (oil shale) difficult to remove; clay particles so close together
• Oil in sandstone easier to extract; sand particles not held as closely together as clay
• Ample supply for at least 40 years
Petroleum/Crude Oil—Pros
oil is relatively cheap easily transported high net energy yield efficient distribution system
Petroleum/Crude Oil—Cons
dependence on oil waste discourages use and exploration of
alternative sources of energy releases CO2 and other pollutants
Fig 15.9—Hubbert’s prediction
Fig 15.7—distillation of petroleum products
Fig 15.8—uses of petroleum products
Natural Gas
composed mainly of methane should last at least 50 years,
depending on Marcellus shale estimates
one of the cleanest burning of all fossil fuels
often found together with oil
Marcellus shale
Hydraulic fracturing
• Also called “fracking”
• Concerns about contamination of ground water and other types of pollution
Natural Gas—Pros
as cheap as oil easily transported high net energy yield burns cleaner
Natural Gas—Cons
must be converted to liquid form for transport (reduces net energy yield)
methane leaks
Coal—Pros
known reserves should last at least 200 years at current rate of use
high net energy yield
West Virginia strip mine
Coal—Cons
accidents and diseases harms land dirtiest fossil fuel to burn high in CO2 and other pollutants
Electricity generation in the US
Fig 15.12—carbon capture
Is there such a thing as “clean coal”?
• Involves carbon capture and sequestration
• Other impurities like sulfur, which contributes to acid rain, must be removed
• Still need to dispose of ash
Fig 15.18—Nuclear fission
Nuclear power—Pros
no air pollutants much less CO2 than fossil fuels water pollution and land disruption
are minimal
Nuclear power—Cons
uranium remains suitable for about 3 years, then needs to be replaced
fuel rods are highly radioactive and few waste facilities exist
low net energy yield but improving terror, nuclear weapons threat
Fig 15.19—light water reactor
Greenhouse effect
• Main greenhouse gas: carbon dioxide
Fig 14.10a—global temp change
Fig 14.10b—Northern Hemisphere temp changes
Climate change—what we know
Carbon dioxide levels have fluctuated; these levels correlate well with changes in surface temps
Fig 14.7—CO2, methane, temps
Intergovernmental Panel on Climate Change (IPCC)
• Established in 1988 by the World Meteorological Organization and the United Nations Environment Program
• IPCC does not conduct research but assesses available peer reviewed and published scientific/technical literature on climate change
• Produces reports about every 5 years
IPCC reports
• 2001 report: In the light of new evidence and taking into account the remaining uncertainties, most of the observed warming over the last 50 years is likely (66-90% chance) to have been due to the increase in greenhouse gas concentrations
• 2007 report: Most of the observed increase in global average temperatures since the mid-20th century is very likely (90-99% chance) due to the observed increase in anthropogenic greenhouse gas concentrations