Chapter
44 Earth’s Resources
The need for energy:-Energy drives all life on earth- Ultimate source of energy for life
is the sun
* Why do you use energy?? * Where does your energy
come from?
4.1 Energy and Mineral Resources
* Renewable resources can be replenished over fairly short spans of time, such as months, years, or decades.
* Nonrenewable resources take millions of years to form and accumulate.
Questions to help evaluate energy resources:
1. How much of the energy source will be available in the future?
2. What is the source’s net energy yield?3. How much will it cost to develop, phase in,
and use?4. How much will extracting, transporting &
using the energy resource that affect the environment?
5. What will using this energy source do to help
sustain the earth?
4.1 Energy and Mineral Resources
Fossil fuels are hydrocarbons that may be used as fuel, including coal, oil,
and natural gas. .
Coal – hydrocarbon rock
Four stages: a. Peatb. Lignite
c. Bituminous coald. Anthracite
Pros: - world most abundant fossil fuel - high energy yield
Cons: - mining is dangerous - dirtiest fuel to burn
- AIR POLLUTION! - Threat to human health
Natural Gas- Mixture of gaseous hydrocarbons.
Pros: - cheaper than oil-reserves expected to last 125+ years-transported easily over land-high energy yield-less air pollution-less environmental damage
Cons: - toxic gas can be produced & released- must be converted to liquid for transportation-leaks in pipes release greenhouse gasses
Petroleum/Oil
Pros: -cheap- easily transported- high net energy yield
Cons: - reserves may be 80% depleted in 44+ years - oil drilling causes land disturbance - produces waste materials- pollution - spills contaminate soil/water- burning fuel releases greenhouse gasses.
Anticlines Are Common Oil Traps
anticline is a fold that is convex up and has its oldest beds at its core
4.2 Alternate Energy Sources
In nuclear fission, the nuclei of heavy atoms such as uranium-235 are bombarded with neutrons.
The uranium nuclei split into smaller nuclei and emit neutrons and heat energy.
Nuclear Power
Pros: - plants don’t emit air pollutants- water pollution & disruption are low- safety measures decrease the likelihood
of a catastrophic event
Cons: - Harmful radiation leaking- Chernobyl & Three Mile Island
- Radioactive waste- must be carefully stored!!
- Expensive upstart
Plant Cooling Towers
Animal Mutations
Plant Mutations
Diablo Canyon Nuclear Plant
Power plant cooled by lake water- note the water release back into the lake. No cooling towers are needed
RENEWABLE ENERGYWe are not using our energy sources
carefully….
- 84 % of all energy used in US is wasted- US wastes close to 2/3 as much as the rest of the world’s population consumes
(300 billion dollars/year)
Solutions:-Reduce individual consumption- Increase energy efficiency
- buy energy-efficient machines - use alternative sources of energy
Benefits of reducing waste:- make non-renewable fossil fuels last longer- give more time to phase in renewable sources-decreases dependence on oil- reduces environmental damage-cheapest & quickest way to prevent global warming- saves money, provides jobs, promotes growth
Need for Alternative Energy - 90% of our energy comes from fossil fuels - energy sources produce pollution
- damages ecosystem - energy resources will not be enough for continued use & a growing population- renewable resources regenerate quickly
Solar Energy
4.2 Alternate Energy Sources
1. Solar energy’s “fuel” is free. Solar energy has two advantages:
2. Solar energy is non-polluting.
Passive solar energy: sun’s energy is collected, stored & distributed. Does not produce electricity!
Ex) southern exposure for a house
Active Solar Energy: Devices are used to collect, store, & circulate Sun’s heat- solar collectors needed
Photovoltaic Cells: a solar cells uses thin wafers of semiconductor materials to produce electricity directly from the sun.
Ex) Solar-powered calculator
Solar PowerPros:
- the sun is free- solar energy is clean & non-polluting- cost of equipment can be recovered by savings
Cons:- Energy source is not constant- devices for harnessing & storing energy are not efficient
Photovoltaic Cell
Wind Energy
4.2 Alternate Energy Sources
In the next 50 to 60 years, wind power could meet between 5 to 10 percent of the country’s demand for electricity.
Aerogenerators are used to harness the power of the wind.
Aerogenerator- vanes like propellers
Aerogenerator- turns like a propeller
Aeroenerator & Darrieus Rotor
Darrieus Roter- Turns on a vertical axis- shaped like an egg beater
- produces energy in low wind speed
Wind Energy
Pros:- wind power is free and unlimited- nonpolluting
Cons:- not constant-wind farms take up a LOT of land-elaborate storage devices needed- interfere with radio & television reception- birds are injured
Hydroelectric Power
4.2 Alternate Energy Sources
The strong water flow that results drives turbines and electric generators.
The water held in a reservoir behind a dam is a form of stored energy that can be released through the dam to produce electric power.
Hydroelectric power is the power generated by falling water.
Glen Canyon Dam
Tidal Power
4.2 Alternate Energy Sources
Tidal power is harnessed by constructing a dam across the mouth of a bay or an estuary in coastal areas.
The strong in-and-out flow of tidal water drives turbines and electric generators.
Tidal Dams
Hydroelectric EnergyPros:
- dams are helpful for flood control- lakes act as recreation areas- little pollution
Cons:- Harm environment- altering water depth and flow- flood area behind the dam- erosion- barrier to fish who must return upstream-Tidal generators can damage wetlands
Geothermal Energy
4.2 Alternate Energy Sources
Hot water is used directly for heating and to turn turbines that generate electric power.
Geothermal energy is harnessed by tapping natural underground reservoirs of steam and hot water.
Geothermal Energy
Pros: -vast & reliable-about 96% less carbon dioxide emissions-competitive cost of producing electric
Cons:-scarcity of reservoir sites-carefully managed-can destroy ecosystems-noise, odor & local climate changes can be problems
The Geysers Is the World’s Largest Electrical Geothermal Facility
Land Resources
4.3 Water, Air, and Land Resources
Earth’s land provides soil and forests, as well as mineral and energy resources
Damage to Land Resources• Mines produce many mineral resources, but
mines are destroying, soil, vegetation, and Earth’s contours.
• Mines also cause soil erosion and pollution that contaminates soil and water and destroys ecosystems.
Surface Mining Destroys Earth’s Surface
Saving Energy