Earth Resources

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