Do Now: Energy Move Clip Answer the following questions in your notebook. 1) What is energy? 2) List...
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Transcript of Do Now: Energy Move Clip Answer the following questions in your notebook. 1) What is energy? 2) List...
Do Now: Energy Move Clip
• Answer the following questions in your notebook.
1) What is energy? 2) List 4 types of energy from the clip.
Aim: How is energy wasted?
Case Study: A Brief History of Human Energy Use
• Everything runs on energy
• Industrial revolution began 275 years ago, relied on wood… led to deforestation
• Today we rely on:
- Coal
- Petroleum products
- Natural gas
Why do you think the world as a whole relies more on renewable energy than
the U.S. does?
Fig. 15-1, p. 370
Net Energy Is the Only Energy That Really Counts
• First law of thermodynamics:– It takes high-quality energy to get high-quality
energy– Ex: Pumping oil from ground, refining it,
transporting it
• Second law of thermodynamics– Some high-quality energy is wasted at every step
Do you understand the 2 laws of thermodynamics?
It Takes Energy to Pump Petroleum
Fig. 15-2, p. 372
Pumping Petroleum Movie Clip
• How do we get oil from the ground?
Net Energy Is the Only Energy That Really Counts
• Net energy – Total amount of useful energy available from a
resource minus the energy needed to make the energy available to consumers
Net Energy Ratio
• Ratio of energy produced to energy used to produce it.
• Conventional oil: high net energy ratio
Do you understand net energy?
Net Energy Ratios
Fig. 15-3, p. 373
Fig. 15-3a, p. 373
Space Heating
Passive solar 5.8
Natural gas 4.9
Oil 4.5
Active solar 1.9
Coal gasification 1.5
Electric heating (coal-fired plant) 0.4
Electric heating (natural-gas-fired plant) 0.4
Electric heating (nuclear plant) 0.3
Fig. 15-3b, p. 373
High-Temperature Industrial Heat
Surface-mined coal 28.2
Underground- mined coal 25.8
Natural gas 4.9
Oil 4.7
Coal gasification 1.5
Direct solar (concentrated) 0.9
Fig. 15-3c, p. 373
Transportation
Natural gas 4.9
Gasoline (refined crude oil)
4.1
Biofuel (ethanol) 1.9
Coal liquefaction 1.4
Oil shale 1.2
Do you understand the net energy ratio?
Energy Resources With Low/Negative Net Energy Yields Need Marketplace Help
• Cannot compete in open markets with alternatives that have higher net energy yields
• Need subsidies from taxpayers…Is this good or bad?
• Nuclear power as an example
Reducing Energy Waste Improves Net Energy
• 84% of all commercial energy used in the U.S. is wasted– 43% after accounting for second law of
thermodynamics
• Drive efficient cars, not gas guzzlers
• Make buildings energy efficient
Summary:
• Typical citizens of advanced industrialized nations each consume as much energy in 6 months as typical citizens in less developed countries consume during their entire life.
• Why is this? Will this ever change?