EVR 1001 Lecture 25: Chapter 8- Energy
Chapter 8- Renewable and Nonrenewable Energy
• We can reduce fossils fuel dependence by reducing demand, and using renewable energy
and biological fuels
• Fossil fuels are derived from biological materials
• Nuclear fuels are mined by radioactive ores
• Commercial energy sources are bought and sold; coal, oil, natural gas
• Subsistence energy sources are gathered by individuals for their own use; wood, charcoal,
animal waste
• 2nd law of thermodynamics: losses will always occur when energy is extracted or used
• 40% of US energy use is to generate electricity, but only 13-40% is available due to
conversion loss
• Fossil fuels are formed by geologic processes acting on biologically-derived materials
• Most coal-burning power plants are about 35% efficient
• Combined cycle natural gas plants can achieve 60% efficiency
• Petroleum: mixture of hydrocarbons, water, and sulfur in underground deposits
• Oil and gasoline are energy- dense fuels fit for automobiles
• Natural gas: can be a component of petroleum, and also separate gaseous deposit; mostly
methane
• Oil sands: slow flowing, viscous deposits of bitumen mixed with sand, water, clay
• Bitumen: a degraded type of petroleum migrates close to the surface
• Bitumen must be mined
• Nuclear fusion powers the sun and other stars; much energy is released but it’s hard to
control
• Nuclear power plants work by using heat from nuclear fission to heat water
o Produces the steam to turn the turbine, which turns a generator
• Fission: a nuclear reaction in which a neutron strikes a relatively large atomic nucleus,
which then splits into two or more parts
• Fuel rods: cylindrical tubes that house the radioactive nuclear fuel
• Control rods: cylindrical devices inserted between fuel rods to slow or stop the fission
reaction by absorbing excess neutrons
• Radioactive waste: produced when the nuclear fuel decays; must be stored in special,
highly secure locations
• High-level radioactive waste- comes from fuel rods
• Low-level radioactive waste- protective clothing, tools, and other items used in nuclear
plants
• At current use, conventional oil will run out in less than 40 years, globally
• The Hubbert curve suggests that new oil reserves will not substantially change the date
by which total petroleum reserves will be depleted
• Coal supplies will last for at least 200 years
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