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Which four sectors require energy?
transportation
industrial
residential and commercial
electric power
True or False: All energy sources are “perfectly clean”
false
No energy sources are “perfectly clean”
What happened to the preindustrial (150+ years ago) energy sources?
energy sources were primarily local
wood, peat, dung
How are energy sources in the present?
far more centralized and distributed
fossil fuels, nuclear energy, electricit
What is a non-renewable resource?
are used and consumer permanently
fossil fuels: oil/petroleum; natural gas; coal
Non-fossil fuels: uranium ore (nuclear energy)
What are renewable sources?
can be readily replenished on human timescales
solar, wind, geothermal, biomass, hydropower
What are advantages of energy sources?
high energy concentration (high energy per unit mass)
versatility (high utility across energy sectors)
safety (low risk to humans and the environment)
Availability (wide geographic distribution)
What are disadvantages of energy sources?
hazard potential (high risk to humans)
environmental damage (high risk to environment)
cost (high cost per unit mass of energy)
What are some nuclear fission characteristics?
Geographic distribution: uranium found in a limited number of places
Portability: fuel can be moved, but must be used in a fixed location
Versatility: Used to generate elctricity
Worst-Case Event: reactor failure and release unlikely, but could cause thousands of deaths and long term contamination
Day-to-Day Pollution: typically low
Climate Change: low after construction
Scale: larger power plants only
Reliability: can run all the time
What are some solar photovoltaic characteristics?
Geographic distribution: widely available
Portability: limited
Versatility: used to generate electricity
Worst-Case Event: low risk
Day-to-Day Pollution: low
Climate Change: very low
Scale: flexible
Reliability: daily and seasonal variability
What are some hydropower characteristics?
Geographic distribution: found in a limited number of places
Portability: cannot be moved
Versatility: mostly used to generate electricity, but sometimes for mechanical energy
Worst-Case Event: dam collapse rare, but could cause thousands of deaths
Day-to-Day Pollution: low but permanent disruption to upstream and downstream ecosystems
Climate Change: low after construction
Scale: flexible but depends on location
Reliability: can run all the time
What are some characteristics of natural gas?
Geographic distribution: found in a limited number of places
Portability: can be piped or trucked; often condensed
Versatility: can be used for cooking, heating, transportation, industry
Worst-Case Event: natural gas plant or pipeline explosion unlikely
Day-to-Day Pollution: lowest of the fossil fuel; can burn easily
Climate Change: highest
Scale: flexible
Reliability: can run all the time
What are some characteristics of coal?
Geographic distribution: found in a limited number of places
Portability: fuel can be moved, but must be used in a fixed area
Versatility: power plant failure could cause some deaths
Worst-Case Event: power plant failure could cause some deaths
Day-to-Day Pollution: difficult to burn cleanly; releases sulfur, nitrogen, and soot to air, land and water
Climate Change: highest
Scale: flexible
Reliability: can run all the time
What are some characteristics of oil?
Geographic distribution: found in a limited number of countries
Portability: highly portable, especially when refined into gasoline, diesel and other fuels
Versatility: highly versatile; can be used for heating, cooking, transportation, industry
Worst-Case Event: refinery accident could cause some deaths
Day-to-Day Pollution: refining can be dirty, burning gasoline, diesel, and other fuels releases pollutants
Climate Change: high
Scale: very flexible
Reliability: can run all the time
What are some characteristics of wind?
Geographic distribution: available in most countries, but not everywhere within those countries
Portability: cannot be moved
Versatility: mostly used to generate electricity, but sometimes for mechanical energy
Worst-Case Event: low risk
Day-to-Day Pollution: low
Climate Change: low
Scale: flexible
Reliability: seasonal and unpredictable variability
What are some characteristics of geothermal?
Geographic distribution: available in most countries, but not everywhere within those countries
Portability: cannot be moved
Versatility: used to generate electricity, occasionally for heating
Worst-Case Event: low risk
Day-to-Day Pollution: low
Climate Change: low
Scale: usually mid to large scale
Reliability: can run all the time
What does industrialized countries dominate more by?
energy consumption worldwide
< 20% of world’s population use 60% of the world’s energy sources
How much percentage does the US represent for the world’s energy consumption?
20%
What is energy efficiency?
amount of available energy in a source that is transformed into useful work
How does energy efficiency work?
ranges from 0-100%
What is energy efficiency for natural gas (cooking)?
about 100%
0% lost since heat is the goal
What is energy efficiency for natural gas (electricity)?
about 60%
40% lost as heat
What is energy efficiency for incandescent bulbs?
about 2.3%
97% lost as heat
What is energy efficiency for fluorescent bulbs?
about 10%
90% lost as heat
What is energy efficiency for light-emitting diodes?
about 20%
80% lost as heat
What is energy intensity?
measure of energy use per $ of GDP, dropping in most countries with increasing energy efficiencies
What is energy savings in appliances and buildings?
super insulated buildings use 70-90% less energy
National Appliance Energy Conservation Act of 198 (NAECA) sets national standards for appliances
2010: energy use saved equal to 51 coal-fired power plants
New push for zero-net-energy buildings
produce as much or more energy than they consume
What are energy efficient commercial buildings?
energy costs associated with buildings can account for about 30% of company operating budget
new push for zero net energy buildings
south facing windows
insulating glass
no furnance
high performing buildings pay for themselves over time
less than 20% less energy consumed
May cost 2-3$ more per square foot initially, saves about 70$ per squiare foot over lifetime of buildings
What is the difference between the past and now for electric power companies?
past to meet future needs: electric utilities planned to build new power plants or purchase additional power from alternative sources
now to meet future needs: increasingly avoid these massive expenses through demand-side management
What is demand-side management?
programs designed to encourage consumers to modify their level and pattern of electricity usage
decreases demand for electricity
cash rewards/incentives to customers who install energy-efficient technologies
energy companies may give away free energy efficient appliances, light bulbs
benefits both customer and electric company
When someone says “most energy from gasoline is wasted” what is meant?
losses through combustion as heat (dominant loss pathway)
braking, idling
friction with road
moving weight of car (not passengers)
inefficient driving habits
What are the modern design improvements from gasoline originally being waster?
use of kevlar and plastics to reduce weight
gasoline-electric hybrid engines (Prius)
Regenerative braking recaptures lost energy
operate at lower temperatures
new US automobile fuel efficiency targets of 54.5 mpg by 2025
including minivans, light trucks, and SUVs
Cars becoming ________ over time, hybrids and electrics also ______ in cost.
more efficient
dropping
What is cogeneration?
production of two useful forms of energy from the same fuel
What does energy conservation do?
can reduce personal usage
What does energy conservation require?
changes in behaviors and practices
reduce commute length
use public transportation or bike to work
turn off lights when not in use
reduce temperature on thermostat at night
What can large scales do to energy conservtion?
large scale changes can be more difficult
allow product prices to reflect true cost of production without subsidies
increase price of gasoline to represent true price, including externalities
When is energy storage helpful?
when energy source timing does not match demand
many energy sources are not available when we want them
too little: solar and wind cannot be intermittent
too much: large coal and nuclear plants are most efficient with constant energy output, not easily shut down when demand is low
What is the solution to many energy resources not being available when wanted?
storage of unused energy
less than 10% efficient
with each conversion, less total energy is available
What are some examples of energy storage?
batteries: most common form, can range in size, stable and hold a charge for extended periods
pumped hydroelectric storage: water is pumped up into the basin behind a dam where it is then available at a later time to generate electricity
compressed air energy storage: when energy is abundant it can be used to compress air in large containers or even in natural or artificially created geological formations
kinetic energy storage: massive flywheel is sped up when energy goes in and used to extract current when needed
What is objective 1 of US energy policy?
increase energy efficiency and conservation
requires many unpopular decisions because need to balance short term loss with long term gain
EX; decrease speed limit to conserve fuel
What is objective 2 of US energy policy?
secure future fossil fuel energy supplies
domestic sources
3 concerns: security, environmental, and economic
What is objective 3 of US energy policy?
develop alternative energy sources
recent policy changes:
consumers to sell energy back to grid
better pricing of alternate sources
Who Should Pay for this? Gas Taxes?
What is objective 4 of US energy policy?
Meet the first three objectives without further damage to the environment
tax fossil fuel use per barrel
What is the energy policy and climate change?
fossil fuels account for 80% of global energy consumption
any policy that addresses climate change must be an energy policy
benefits are global, but often difficult for individual companies to capture
short term individual incentives push towards more consumption not less
Well designed policies can promote commitments to technologies and practices with long-term benefits
