energy sources

Ch 10 Energy• Energy Sources and Uses• Coal - Oil - Natural Gas• Nuclear Power• Conservation• Solar Energy

– Photovoltaic Cells

• Fuel Cells• Energy From Biomass• Energy From Earth’s Forces

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The capacity to do work

heat, light, electricity, and chemical energy are all types of energy

Energy Sources and Uses

• Energy - The capacity to do work.• Work - Application of force through a distance. • Power - Rate at which work is done or rate of flow

of energy.Units of energy– Joule - Amount of work done when a force of

1 Newton is exerted over 1 meter (or about 0.238cal).

– Calorie - Amount of energy necessary to heat 1 gram of water 1oC.

– Watt - 1 joule/sec3

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Daily Per Capita Human Energy Consumption through Time

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Per Capita/yr Energy Use and GDP

Source: Massachusetts Institute of Technology

The higher the standard of living, the greater the use of energy.United States: 5% of the world’s population, uses about 20% of the total energy

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Per Capita Consumption• On average, each person in the U.S. and

Canada uses more than 300 GJ of energy annually.

• In poorest countries of the world, each person generally consumes less than one GJ annually.

• Richest 20 countries consume annually :– nearly 80% of natural gas,

– 65% of oil, and

– 50% of coal production.

Energy Consumption per Capita

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Energy Consumption Profiles in OECD and non-OECD Countries, 2000(Organization for Economic Co-operation and Development – 30 members)

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(most Industrialized Nations)

OECD – Europe, North America, Japan, Korea, Turkey, Australia, and New ZealandNon-OECD – includes Russia, China, Brazil, Argentina, and other smaller and

developing nations.

How We Use Energy in the US• Industry - 33%• Residential, commercial buildings - 38%• Transportation - 27%• About 50% of all the energy in primary fuels is lost

– during conversion to more useful forms (eg, 2/3 energy of coal lost in thermal conversion, ie, combustion),

– while being shipped to the site of end use, or (eg, 10% energy lost in transmission lines)

– during use.

• Natural gas is our most efficient fossil fuel (10% lost during processing & shipping, 75-95% efficient in furnaces).

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Worldwide Commercial Energy Consumption

10BP 2003

U.S. Energy Flow, 2002 (quadrillion Btu or quads)

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World Fossil Fuel Consumption

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Renewable Resources

Resources that can be replaced within a few human generations.

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Nonrenewable Resources

Resources that cannot be replaced within a few human generations.

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Renewable vs Nonrenewable Resources

Renewable• Alternative fuels

– Solar power– Biomass– Hydropower

Nonrenewable• Fossil fuels

– Oil– Coal– Natural Gas

• Ore deposits of metals

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What is a Resource?

Source of raw material

used by society

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How can it be used sustainably?

Resource Management

Maximum Sustainable Yield (MSY) is :

harvest rate = renewal rate

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IF the

Harvest rate > Renewable rate

Then the renewable resource can become

Depleted in the short term18

Fossil Fuels

• Fossil fuels - organic chemicals that were created by living organisms millions of years ago, buried in sediments, and transformed into energy-rich compounds

• Because fossil fuels take so long to form, they are essentially nonrenewable resources.

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Coal Extraction and Use• Mining & drainage -

dangerous to humans and the environment

• Coal burning releases large amounts of air pollution (CO2, SO2, NOx , dust, heavy metals, etc), and is the largest single source of acid rain in many areas.

• Economic damages - billions of dollars

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• One of the largest and most controversial strip mines is at Black Mesa, Arizona

• Partially located on Hopi Indian land• Relies on non-renewable 10,000 year old

groundwater to transport coal slurry

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Oil Extraction and Use• The Middle East control two-thirds of all known

oil reserves.

• The U.S. has already used up about 40% of its original recoverable petroleum resource.– Drilling - soil and water pollution

– Combustion - substantial air pollution

– Controversies – ANWR, Coastal Drilling

Photo: Associated press24

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Crude Oil Prices

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Natural Gas Consumption

• Natural gas produces only half as much CO2 as an energy-equivalent amount of coal.

• Problems: – difficult to ship

across oceans or to store in large quantities

– Flaring off - wasted

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Nuclear Power

• “Atoms for Peace” in 1953 by Eisenhower (produce enough power ‘to cheap to monitor’)

• Nuclear power now produces only about 7% of the U.S. energy supply.

• Problems have made nuclear power much less attractive than was originally expected :

– construction costs and

– safety concerns and….

– waste disposal.28

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Distribution of Nuclear Power Plants in North

America

Nuclear EnergyTwo types of nuclear power & both involve

rearranging the structure of the atom.– Fission - splitting of a radioactive isotope of a heavy

element into daughter products (smaller atoms) with the release of energy

– Fusion - joining of isotopes of a light element into a heavier element with the release of energy.

• All commercial energy generation is run by fission.

• The Sun generates heat and light by fusion.

• Some nuclear weapons use fusion reactions but controlled fusion is still in the developmental stage.

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Chernobyl - 1986

Accidents???

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Public alarm but was under control.

Reactors in US are different than the one in Chernobyl

and are MUCH safer!!

Bad accident!!! Also poor reactor design

Three Mile Island - 1979

Nuclear Wastes

• One of the most difficult problems associated with nuclear power is the disposal of wastes produced during mining, fuel production, reactor operation, and decommissioning of reactors.

• Ocean dumping – until 1970?

• Radioactive mine wastes, mill tailings

• Dry cask storage

• High-level waste repository - Yucca Mountain, NV??

• Monitored, retrievable storage?

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1965+ - former Soviet Union disposed of 18

nuclear reactors (7 w/ fuel in the Kara Sea)

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Arctic Ocean permanently contaminated?

• Hanford buried radioactive waste which began leaking, esp into the ground water & Columbia River. Shut down in 1960s.

• Nuclear testing peaks in 1950-60s. Trees absorb cesium which accumulates in

wood.

Plant roots absorbed the radioactive material and transported it to the ground surface.

Wood ash from trees growing during this time period can be radioactive – 100X higher cesium than other environmental samples.

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• Utilization Efficiencies– Most potential energy in fuel is lost as

– In response to 1970’s oil prices, average US automobile gas-mileage increased from 13 mpg in 1975 to 28.8 mpg in 1988.

–Falling fuel prices of the 1980’s discouraged further conservation.

ENERGY CONSERVATION

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waste heat.

Corporate Average Fuel Economy

US Dept of Transportation, March 2005

Find more non-renewable

oil?

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Eg, Arctic National Wildlife Refuge

Hybrid gas-

electric engines

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Energy Conversion Efficiencies

• Energy Efficiency is a measure of energy produced compared to energy consumed.– Household energy losses can be reduced by

one-half to three-fourths by using better insulation, double-paned glass, protective covers, and general sealing procedures.(Indoor Pollution?)• Orient homes to gain advantage of passive

solar gain in the winter.40

Heat Losses

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High heat losses = white, red, orange(Miller 2006)

Increasing Home Insulation

Standard Insulation in U.S. homes = R-12 – R-19 Super-Insulated Homes = R-25 – R-60Super-insulated homes in Sweden use 90% less energy for heating and cooling than typical homes in the U.S.

Mesa Verde NP (SW USA) – many energy efficient features

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Domestic Energy Efficiency

Earth-sheltered house in Taos, New Mexico

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Buying energy-efficient appliances can cut your energy consumption considerably.

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