Energy

1
Energy
2
Different forms of energy

• Mechanical energy - kinetic and potential (used
  by machines, natural landslides, avalanches,
  rain)
• Nuclear energy - unstable nuclei throw off
  particles)
• Thermal energy - internal energy due to to
  motion of atoms (hot springs, volcanoes, steam
  engines)
• Electrical energy - stored in motion of electrons
  (lightning)
• Chemical energy stored in chemical form fuels,
  sugars, batteries (sucrose, methane, ethanol ,
  methanol)
• Radiant energy electromagnetic energy (chemical
  storage of photosynthesis, phosphorescence)

3
Conservation of Energy

• Energy never lost only transformed
• Amount of energy in the universe does not change
• Energy in different form has different uses
• Lowest energy types are thermal (friction) and
  deformation (stretch string or bent rod)

4
Energy Usages

• Those affecting GHG emissions the most
• Electricity generation
• Transportation (automobiles, trucks, trains,
  planes)

5
Electricity

• Produced from different sources
• Burning coal, oil or gas
• Nuclear energy
• Solar, wind, hydro sources
• Electricity often preferred because
• Clean
• Convenient safe
• Easy to control
• Easy to transport
• Main disadvantage in comparison to direct usage
  of coal, gas or oil is cost

6
Electric Energy

• Generation Power plants using different fuels
• Transmission of electric energy generating
  plants distribute energy through transmission
  lines with high voltage
• Transformers are used to change (increase or
  decrease) the voltage linked to transmission
• Transformation of electric energy in mechanical
  or other energy - Electric motors

7
Electricity Generating Processes

• Conventional electricity sources fossil-fuel
  and nuclear energy
• both methods generate waste and use water to
  transfer energy between low and high temperature
  reservoirs
• Fossil fuel and nuclear process Power Plants.ppt

8
Fossil Fuel Resources

• Coal, oil and gas Fig 11.1 coal and oil
  production.ppt
• Incredibly cheap energy (no real tax)
• Real costs of oil much higher
• Support of Gulf wars
• Tax credits given to oil producers
• Cost of fuel research
• Health consequences of combustion
• Waste seepages
• Capping old wells
• Large oil spills
• Consequences of low oil prices
• Boon to air travel
• Consumers buy larger cars

9
Coal

• Emphasis on coal in recent developments
• Reserves are huge in the world
• Coal comes from various grades (anthracite,
  bituminous, subbituminous, lignite)
• Waste is affecting the environment
• Cost of transport is higher than cost of oil
• Burning coal produces several pollutants
• Waste heat
• Acid rain (nitrogen and sulfur oxides)
• CO2 (more emitted by coal than methane)

10
Strategies for coal cleaning gasification and
liquefaction

• Relatively cheap to remove sulfur and other
  impurities from gas
• Fluids are easily moved by pipeline
• Current mix of fuel sources

11
Transportation

• Cost of owning a car
• Cost of car
• Fuel Mileage (relationship weight mileage)
• Speed
• Number of miles driven
• Pollution from cars
• CO, nitrous oxide (NOx), SOx, fine particulates,
  reactive organic gases, photochemical smog
  (unburned HC interacting with sunlight), lead
• Catalytic converter gt reduces CO, NOx gt
  increases fuel mileage
• Most dangerous CO and lead

12
Auto fuel economy

• Automobile sector of US economy
• ¼ retail sales
• 10 personal consumption
• 8.5 gross national product
• Changes in car typegt layoffs at US car makers
• Corporate Average Fuel Economy (CAFE)
• Various efficiency measures (drag, weight, )
• Available technology could raise fuel economy but
  costs associated
• Economy and Pollution real cost?
• Economy vs. safety (20-25 death due to car
  accidents)

13
Other Modes of Transportation

• Long-distance mass transit
• Movement of goods
• Trucks vs. railroads
• Air traffic
• Transport of fuel
• Pipelines
• Oil at sea

14
Energy from Nuclear Reactors

• All forms of nuclear energy involves production
  of steam to drive turbines
• Fission process in reactors involves the break
  up of a nucleus into smaller parts
• Conventional reactor types
• boiling water reactors (BWR)
• Pressurized water reactors (PWR)
• High temperature gas cooled reactors (HTGR)
• Graphite water reactors

15
Enrichment of Uranium

• For BWR and PWR to work they need suitable
  mixture of U 235 and U 238
• In naturally occurring Uranium ore U 235 is only
  0.7
• To be useful it must be increased to 4
• Enrichment done by gaseous diffusion (through
  membrane) but very costly in energy
• Other processes less costly
• gas centrifuge
• laser enrichment

16
Problems with Nuclear Energy

• Safety
• Public mistrust of nuclear energy (leaks,
  accidents)
• Health effects of ionizing radiation exposure
  and dose (quality x exposure
• Industrial waste
• Radon
• Reactor safety standards
• Waste
• Reprocessing of Plutonium - dangerous because
  could be used to build bombs
• Health problems
• Storage of radioactive waste (e.g., geologic
  formations Yucca Mountains, space)
  vitrification (enclosure in glass)

17
Renewable Energy

• Solar Energy
• Photovoltaic cells
• Large-scale solar energy projects (Central
  receivers focusing mirrors, Solar farms,
  Parabolic troughs and dishes)
• Hydroelectricity
• Energy from the ocean
• energy in tides, Ocean thermal energy conversion,
  wave energy
• Biomass energy

18
Energy and GHG emissions

• High energy dependence and consumption gt high
  GHG emissions.
• Global primary energy use by sectors
• Industry 2/5
• Commercial and residential structures 2/5
• Transportation for 1/5
• Different regions can follow different
  development paths, and even at similar levels of
  economic growth there are some persistent
  differences in primary energy use patterns.

19
Energy Dependence

• Factors that affect energy dependence
• changes in consumer preferences
• energy and technology costs
• settlement and infrastructure patterns
• technological progress
• While energy dependence is an important indicator
  of GHG emissions, the type of energy used is even
  more significant. A fossil fuel intensive society
  will result in high GHG emission levels.