Enviar búsqueda
Cargar
Conventional Energy Alternatives
•
3 recomendaciones
•
2,460 vistas
T
tahyde
Seguir
APES Conventional Energy Alternatives
Leer menos
Leer más
Educación
Denunciar
Compartir
Denunciar
Compartir
1 de 57
Descargar ahora
Descargar para leer sin conexión
Recomendados
Environmental health and Toxicology
Environmental health and Toxicology
Nova Corciega
APES Ch. 1, part 2
APES Ch. 1, part 2
Stephanie Beck
Global climate change
Global climate change
David Whiting
Agri runoff and coastal zone
Agri runoff and coastal zone
JEEVAN GOWDA
What is Climate Change?And Consequences of Climate change
What is Climate Change?And Consequences of Climate change
Saica__88
Summary of topic 4.1
Summary of topic 4.1
Michael Smith
Forest Habitats and Climate Change
Forest Habitats and Climate Change
Northern Institute of Applied Climate Science
Global and local environmental problems
Global and local environmental problems
Liz Duran
Más contenido relacionado
La actualidad más candente
Renewable energy resources
Renewable energy resources
shalini2093
Earth Day Celebration 2020 (1)
Earth Day Celebration 2020 (1)
Dr.Shubhalaxmi Vaylure
Climate Change 2016
Climate Change 2016
"Mark "Mac"" McAdoo, DBA
Chapter 9.3: Matter and Energy in Ecosystems
Chapter 9.3: Matter and Energy in Ecosystems
Dwayne Squires
The three mile island vaibhav
The three mile island vaibhav
vaibhav mangal
Renewable energy scenario in india opportunities and challenges
Renewable energy scenario in india opportunities and challenges
Surjeet Randhir Singh Dhaka
Environmental Disasters
Environmental Disasters
DYUTI Conference
ENERGY CRISIS
ENERGY CRISIS
SVCE
Desertification
Desertification
Ilenya Dimech
Climate change
Climate change
Akhil Sharma
Current and emerging issues in the environment
Current and emerging issues in the environment
Standee pinky Weah
Climate change
Climate change
Elaine Yu
Eco Schools Presentation
Eco Schools Presentation
Cui-Li Lim
Climate change
Climate change
Bakr Younis /Al-Azhar University – Gaza
What is the energy of the future?
What is the energy of the future?
Nicolas Meilhan
Environmental resource depletion and poverty
Environmental resource depletion and poverty
Muhammad Faisal
Climate changes
Climate changes
MujahidAli130
Chapter 8 - O'Neill PPoint
Chapter 8 - O'Neill PPoint
tfix44
Growth in a Finite World - Sustainability and the Exponential Function
Growth in a Finite World - Sustainability and the Exponential Function
Toni Menninger
System & models one mark answer
System & models one mark answer
GURU CHARAN KUMAR
La actualidad más candente
(20)
Renewable energy resources
Renewable energy resources
Earth Day Celebration 2020 (1)
Earth Day Celebration 2020 (1)
Climate Change 2016
Climate Change 2016
Chapter 9.3: Matter and Energy in Ecosystems
Chapter 9.3: Matter and Energy in Ecosystems
The three mile island vaibhav
The three mile island vaibhav
Renewable energy scenario in india opportunities and challenges
Renewable energy scenario in india opportunities and challenges
Environmental Disasters
Environmental Disasters
ENERGY CRISIS
ENERGY CRISIS
Desertification
Desertification
Climate change
Climate change
Current and emerging issues in the environment
Current and emerging issues in the environment
Climate change
Climate change
Eco Schools Presentation
Eco Schools Presentation
Climate change
Climate change
What is the energy of the future?
What is the energy of the future?
Environmental resource depletion and poverty
Environmental resource depletion and poverty
Climate changes
Climate changes
Chapter 8 - O'Neill PPoint
Chapter 8 - O'Neill PPoint
Growth in a Finite World - Sustainability and the Exponential Function
Growth in a Finite World - Sustainability and the Exponential Function
System & models one mark answer
System & models one mark answer
Destacado
19 lecture Fossil Fuels
19 lecture Fossil Fuels
tahyde
New Renewable resources
New Renewable resources
tahyde
Nox and sox emission control
Nox and sox emission control
REDEMPTO
Effects of air pollution m3
Effects of air pollution m3
Bibhabasu Mohanty
Renewable Energy Sources
Renewable Energy Sources
Stoyan Dimitrov
Hy wire-car
Hy wire-car
SARATH PRAKASH
Destacado
(6)
19 lecture Fossil Fuels
19 lecture Fossil Fuels
New Renewable resources
New Renewable resources
Nox and sox emission control
Nox and sox emission control
Effects of air pollution m3
Effects of air pollution m3
Renewable Energy Sources
Renewable Energy Sources
Hy wire-car
Hy wire-car
Similar a Conventional Energy Alternatives
Ch20 lecture 3e
Ch20 lecture 3e
Asma Wasim
Nuclear
Nuclear
Gulfam Hussain
Ch20 lecture 3e
Ch20 lecture 3e
AHS
Nuclear Energy: Safe, Clean, and Reliable The benefits and misperceptions of ...
Nuclear Energy: Safe, Clean, and Reliable The benefits and misperceptions of ...
Society of Women Engineers
Nuclear energy group n0 12
Nuclear energy group n0 12
ShibbirAhamad
Nuclear Power Plant
Nuclear Power Plant
Ahmed A. Arefin
Nuclear_Engineering_Basics.pptx
Nuclear_Engineering_Basics.pptx
VishalMeena66
Nuclear energy PPT
Nuclear energy PPT
vandanalath
Ch 13 nuclear energy
Ch 13 nuclear energy
TadviDevarshi
4 chapter 4 nuclear power station 4-1
4 chapter 4 nuclear power station 4-1
Prof . Ghada Amer
Nuclear energy powerpoint.
Nuclear energy powerpoint.
Enigmatic You
NuclearEnergy.pptx
NuclearEnergy.pptx
mamoun3
Lecture 10 nuclear
Lecture 10 nuclear
Malcolm Harrison
Nuclear energy
Nuclear energy
hetdedhia
Accidents in nuclear power plants
Accidents in nuclear power plants
Melwyn Mayers
19 business i environment i society mba 2016
19 business i environment i society mba 2016
Rajesh Satpathy, Regional College of Management (RCM), Bhubaneswar
Unit 4 ch 17 s2 nuclear energy
Unit 4 ch 17 s2 nuclear energy
wja10255
Advances in power generation
Advances in power generation
Ketan Pitrubhakta
The think quest project
The think quest project
Esu Helwan
Chapter 10 – energy sources, work and power
Chapter 10 – energy sources, work and power
Justy5
Similar a Conventional Energy Alternatives
(20)
Ch20 lecture 3e
Ch20 lecture 3e
Nuclear
Nuclear
Ch20 lecture 3e
Ch20 lecture 3e
Nuclear Energy: Safe, Clean, and Reliable The benefits and misperceptions of ...
Nuclear Energy: Safe, Clean, and Reliable The benefits and misperceptions of ...
Nuclear energy group n0 12
Nuclear energy group n0 12
Nuclear Power Plant
Nuclear Power Plant
Nuclear_Engineering_Basics.pptx
Nuclear_Engineering_Basics.pptx
Nuclear energy PPT
Nuclear energy PPT
Ch 13 nuclear energy
Ch 13 nuclear energy
4 chapter 4 nuclear power station 4-1
4 chapter 4 nuclear power station 4-1
Nuclear energy powerpoint.
Nuclear energy powerpoint.
NuclearEnergy.pptx
NuclearEnergy.pptx
Lecture 10 nuclear
Lecture 10 nuclear
Nuclear energy
Nuclear energy
Accidents in nuclear power plants
Accidents in nuclear power plants
19 business i environment i society mba 2016
19 business i environment i society mba 2016
Unit 4 ch 17 s2 nuclear energy
Unit 4 ch 17 s2 nuclear energy
Advances in power generation
Advances in power generation
The think quest project
The think quest project
Chapter 10 – energy sources, work and power
Chapter 10 – energy sources, work and power
Último
2024.03.23 What do successful readers do - Sandy Millin for PARK.pptx
2024.03.23 What do successful readers do - Sandy Millin for PARK.pptx
Sandy Millin
How to Use api.constrains ( ) in Odoo 17
How to Use api.constrains ( ) in Odoo 17
Celine George
In - Vivo and In - Vitro Correlation.pptx
In - Vivo and In - Vitro Correlation.pptx
AditiChauhan701637
Maximizing Impact_ Nonprofit Website Planning, Budgeting, and Design.pdf
Maximizing Impact_ Nonprofit Website Planning, Budgeting, and Design.pdf
TechSoup
Finals of Kant get Marx 2.0 : a general politics quiz
Finals of Kant get Marx 2.0 : a general politics quiz
Conquiztadors- the Quiz Society of Sri Venkateswara College
How to Manage Cross-Selling in Odoo 17 Sales
How to Manage Cross-Selling in Odoo 17 Sales
Celine George
How to Add Existing Field in One2Many Tree View in Odoo 17
How to Add Existing Field in One2Many Tree View in Odoo 17
Celine George
UKCGE Parental Leave Discussion March 2024
UKCGE Parental Leave Discussion March 2024
UKCGE
How to Show Error_Warning Messages in Odoo 17
How to Show Error_Warning Messages in Odoo 17
Celine George
Clinical Pharmacy Introduction to Clinical Pharmacy, Concept of clinical pptx
Clinical Pharmacy Introduction to Clinical Pharmacy, Concept of clinical pptx
raviapr7
3.21.24 The Origins of Black Power.pptx
3.21.24 The Origins of Black Power.pptx
mary850239
Prelims of Kant get Marx 2.0: a general politics quiz
Prelims of Kant get Marx 2.0: a general politics quiz
Conquiztadors- the Quiz Society of Sri Venkateswara College
CAULIFLOWER BREEDING 1 Parmar pptx
CAULIFLOWER BREEDING 1 Parmar pptx
SaurabhParmar42
Diploma in Nursing Admission Test Question Solution 2023.pdf
Diploma in Nursing Admission Test Question Solution 2023.pdf
MohonDas
Education and training program in the hospital APR.pptx
Education and training program in the hospital APR.pptx
raviapr7
What is the Future of QuickBooks DeskTop?
What is the Future of QuickBooks DeskTop?
TechSoup
How to Make a Field read-only in Odoo 17
How to Make a Field read-only in Odoo 17
Celine George
Ultra structure and life cycle of Plasmodium.pptx
Ultra structure and life cycle of Plasmodium.pptx
Dr. Asif Anas
5 charts on South Africa as a source country for international student recrui...
5 charts on South Africa as a source country for international student recrui...
CaraSkikne1
The Singapore Teaching Practice document
The Singapore Teaching Practice document
Xsasf Sfdfasd
Último
(20)
2024.03.23 What do successful readers do - Sandy Millin for PARK.pptx
2024.03.23 What do successful readers do - Sandy Millin for PARK.pptx
How to Use api.constrains ( ) in Odoo 17
How to Use api.constrains ( ) in Odoo 17
In - Vivo and In - Vitro Correlation.pptx
In - Vivo and In - Vitro Correlation.pptx
Maximizing Impact_ Nonprofit Website Planning, Budgeting, and Design.pdf
Maximizing Impact_ Nonprofit Website Planning, Budgeting, and Design.pdf
Finals of Kant get Marx 2.0 : a general politics quiz
Finals of Kant get Marx 2.0 : a general politics quiz
How to Manage Cross-Selling in Odoo 17 Sales
How to Manage Cross-Selling in Odoo 17 Sales
How to Add Existing Field in One2Many Tree View in Odoo 17
How to Add Existing Field in One2Many Tree View in Odoo 17
UKCGE Parental Leave Discussion March 2024
UKCGE Parental Leave Discussion March 2024
How to Show Error_Warning Messages in Odoo 17
How to Show Error_Warning Messages in Odoo 17
Clinical Pharmacy Introduction to Clinical Pharmacy, Concept of clinical pptx
Clinical Pharmacy Introduction to Clinical Pharmacy, Concept of clinical pptx
3.21.24 The Origins of Black Power.pptx
3.21.24 The Origins of Black Power.pptx
Prelims of Kant get Marx 2.0: a general politics quiz
Prelims of Kant get Marx 2.0: a general politics quiz
CAULIFLOWER BREEDING 1 Parmar pptx
CAULIFLOWER BREEDING 1 Parmar pptx
Diploma in Nursing Admission Test Question Solution 2023.pdf
Diploma in Nursing Admission Test Question Solution 2023.pdf
Education and training program in the hospital APR.pptx
Education and training program in the hospital APR.pptx
What is the Future of QuickBooks DeskTop?
What is the Future of QuickBooks DeskTop?
How to Make a Field read-only in Odoo 17
How to Make a Field read-only in Odoo 17
Ultra structure and life cycle of Plasmodium.pptx
Ultra structure and life cycle of Plasmodium.pptx
5 charts on South Africa as a source country for international student recrui...
5 charts on South Africa as a source country for international student recrui...
The Singapore Teaching Practice document
The Singapore Teaching Practice document
Conventional Energy Alternatives
1.
Lecture Outlines Chapter 20 Environment: The
Science behind the Stories 4th Edition Withgott/Brennan © 2011 Pearson Education, Inc.
2.
This lecture will
help you understand: • Reasons for seeking alternative fuels • Contributions to world energy by alternative fuels • Nuclear energy • The social debate over nuclear power • Bioenergy • Hydroelectric power © 2011 Pearson Education, Inc.
3.
Central Case: Sweden’s
search for alternative energy • In 1980, Sweden’s people voted to phase out nuclear energy • The government has promoted hydroelectric, biomass, and wind power • Sweden will still use nuclear power instead of fossil fuels • Public support for nuclear power has increased © 2011 Pearson Education, Inc.
4.
Alternatives to fossil
fuels • Our global economy is powered by fossil fuels - These fuels also power ⅔ of electricity generation • Fossil fuels are limited and pollute - We need to shift to resources that are less easily depleted and environmentally gentler © 2011 Pearson Education, Inc.
5.
Conventional alternatives • We
have alternatives to fossil fuels - They are renewable and less polluting and harmful • But they are more expensive in the short term when external costs are not included in market prices • The most widely used “conventional alternatives” to fossil fuels: - Nuclear, hydroelectric, and biomass energy • They exert less environmental impact - These are intermediates along a continuum of renewability © 2011 Pearson Education, Inc.
6.
The U.S. relies
on fossil fuels • The U.S. relies more on fossil fuels and nuclear power than other countries • Conventional alternatives play minor, yet substantial, roles • The use of conventional alternatives has been growing more slowly than fossil fuels © 2011 Pearson Education, Inc.
7.
Nuclear power • Nuclear
energy occupies an odd and conflicted position in our debate over energy • It is free of air pollution produced by fossil fuels - Yet it has been clouded by weaponry, waste disposal, and accidents • Public safety concerns have led to limited development • The U.S. generates the most electricity from nuclear power - But only 20% of U.S. electricity comes from nuclear - France gets 76% of its electricity from nuclear power © 2011 Pearson Education, Inc.
8.
Fission releases nuclear
energy Nuclei of large atoms are bombarded with neutrons, releasing energy and neutrons • Nuclear energy = the energy that holds together protons and neutrons within the nucleus of an atom • Nuclear fission = the splitting apart of atomic nuclei - The reaction that drives the release of nuclear energy in power plants • This chain reaction keeps a constant output of energy © 2011 Pearson Education, Inc.
9.
Nuclear energy comes
from uranium • Nuclear reactors = facilities within nuclear power plants • Nuclear fuel cycle = the process that begins when uranium is mined • Radioisotopes = emit subatomic particles and high-energy radiation as they decay into lighter radioisotopes - They become stable isotopes Uranium is used for • Uranium-235 decays into lead- nuclear power because it is radioactive 207 © 2011 Pearson Education, Inc.
10.
Nuclear reactors use
uranium-235 • Over 99% of uranium occurs as uranium-238 (238U) - It does not emit enough neutrons for a chain reaction - So we use 235U, with a half-life of 700 million years • 235U is enriched to 3% and formed into pellets (UO2) - Which are incorporated into fuel rods used in nuclear reactors • After several years in a reactor, uranium is depleted - The fuel no longer generates enough energy • Spent fuel can be reprocessed, but it is expensive - So it is disposed of as radioactive waste © 2011 Pearson Education, Inc.
11.
Fission in reactors
generates electricity • A moderator = a substance (water or graphite) that slows the neutrons bombarding uranium - Allows fission to begin in a nuclear reactor - Excess neutrons must be soaked up • Control rods = a metallic alloy that absorbs neutrons - They are placed into the reactor among the waterbathed fuel rods - They are moved into and out of the water to control the rate of the reaction © 2011 Pearson Education, Inc.
12.
A nuclear power
plant • The reactor core is housed in a reactor vessel - The vessel, steam generator, and plumbing are located in a containment building • Containment buildings are constructed to prevent leaks of radioactivity due to accidents or natural catastrophes - Not all nations require containment buildings © 2011 Pearson Education, Inc.
13.
A typical light
water reactor © 2011 Pearson Education, Inc.
14.
Breeder reactors make
better use of fuel • Breeder reactors use 238U (normally a waste product) - A neutron is added to 238U to form 239Pu (plutonium) • They make better use of fuel, generate more power, and produce less waste • But breeder reactors are more dangerous than conventional reactors - Its highly reactive coolant raises the risk of explosions - Plutonium can be used in nuclear weapons - They also are more expensive • Most of the world’s breeder reactors have been closed © 2011 Pearson Education, Inc.
15.
Fusion remains a
dream Tremendous energy is released when deuterium and tritium are fused to form helium • Nuclear fusion = forces together small nuclei of lightweight elements under extremely high temperature and pressure • Drives the sun’s output of energy and hydrogen (thermonuclear) bombs • If we could control fusion, we could produce vast amounts of energy from water © 2011 Pearson Education, Inc.
16.
Nuclear power delivers
energy cleanly • Nuclear power helps us avoid emitting 600 million metric tons of carbon each year • Power plants pose fewer health risks from pollution - They are safer for workers than coal-fired plants • Uranium mining damages less land than coal mining • Drawbacks of nuclear power: - Nuclear waste is radioactive - If an accident or sabotage occurs, the consequences can be catastrophic • The world has 436 operating nuclear plants in 30 nations © 2011 Pearson Education, Inc.
17.
Coal versus nuclear
power © 2011 Pearson Education, Inc.
18.
Nuclear power poses
small risks, but… • It poses the possibility of catastrophic accidents • The most serious accident in the U.S. = Three Mile Island in Pennsylvania in 1979 • Meltdown = coolant water drained from the reactor • Temperatures rose inside the reactor core … • Melting the metal surrounding the fuel rods … • Releasing radiation The emergency could have been far worse © 2011 Pearson Education, Inc.
19.
Chernobyl was the
worst accident yet • 1986 explosion at the Chernobyl plant in Ukraine - The most severe nuclear plant accident ever seen - It was due to human error and unsafe design • For 10 days, radiation escaped while crews tried to put out the fire - More than 100,000 residents were evacuated • The landscape for 19 miles still remains contaminated • The accident killed 31 people directly - Thousands more became sick or developed cancer © 2011 Pearson Education, Inc.
20.
The Chernobyl accident The
destroyed reactor was encased in a massive concrete sarcophagus, which is still leaking radioactive material © 2011 Pearson Education, Inc.
21.
Radioactivity from Chernobyl
spread widely Atmospheric currents carried radioactive fallout from Chernobyl across much of the Northern Hemisphere © 2011 Pearson Education, Inc.
22.
Smaller-scale accidents have
occurred • Western reactors are safer than Chernobyl - But smaller accidents have occurred - A 1999 accident in Japan killed two workers and exposed 400 others to radiation • Aging plants require more maintenance and are less safe - Recent terrorist attacks raised fears that similar attacks could be carried out against nuclear plants - Or stolen radioactive material could be used in attacks • The U.S. “megatons to megawatts” program buys radioactive material from the former Soviet Union - Using it in power plants © 2011 Pearson Education, Inc.
23.
Waste disposal remains
a problem • Spent fuel rods and all other waste must be put in a safe location - Where leaking radioactivity will not harm future generations • Waste is held in temporary storage - Spent rods are stored in water • U.S. plants are running out of room - Waste is now stored in thick barrels of steel, lead, and concrete © 2011 Pearson Education, Inc.
24.
U.S. storage of
high-level radioactive waste • Waste is held at 125 sites in 39 states • 161 million citizens live within 75 miles of nuclear waste © 2011 Pearson Education, Inc.
25.
Waste storage at
Yucca Mountain, Nevada • It is safer to store all waste in a central repository - It can be heavily guarded • Yucca Mountain, Nevada was chosen for this site - President Obama’s administration does not support it • So waste will remain at its current locations © 2011 Pearson Education, Inc.
26.
Yucca Mountain, Nevada ©
2011 Pearson Education, Inc.
27.
Benefits of storing
waste at Yucca Mountain • It is remote and unpopulated • It has minimal risk of earthquakes that could damage the tunnels and release radioactivity • Its dry climate reduces chances of groundwater contamination • The water table is deep underground, making groundwater contamination less likely • It is on federal land that can be protected from sabotage © 2011 Pearson Education, Inc.
28.
Concerns with Yucca
Mountain as a site • Some argue that earthquakes and volcanoes could destabilize the site’s geology • Fissures in the rock could allow rainwater to seep into the caverns • Nuclear waste will need to be transported there - From current storage areas, and from future nuclear plants and military installations - Shipments by rail and truck over thousands of miles could cause a high risk of accident or sabotage © 2011 Pearson Education, Inc.
29.
Dilemmas slow nuclear
power’s growth • Concerns over waste disposal, safety, and costs have affected nuclear power’s growth • It is enormously expensive to build, maintain, operate, and ensure the safety of nuclear facilities - Decommissioning plants can be more expensive than construction • Power plants serve less than half their expected lifetimes • Electricity costs more than from coal and other sources - Governments must subsidize nuclear power © 2011 Pearson Education, Inc.
30.
The future of
nuclear energy • 75% of nuclear power plants in Western Europe will be retired by 2030 - But some nations are rethinking this because of concerns over climate change • Asian nations are increasing nuclear capacity - 56 plants are under construction • The U.S. nuclear industry has stopped building plants - Expanding nuclear capacity would decrease reliance on fossil fuels and cut greenhouse gas emissions - Engineers are planning ways to make nuclear power plants safer and less expensive © 2011 Pearson Education, Inc.
31.
Bioenergy • Bioenergy (biomass
energy) = energy obtained from organic material that makes up organisms - Wood, charcoal, agricultural crops, manure • Bioenergy has great potential for addressing our energy challenges Over 1 billion people use wood for heat, cooking, and light © 2011 Pearson Education, Inc.
32.
Overharvesting and developing
new sources • Biomass is only renewable if it is not overharvested - Overharvesting causes deforestation, erosion, and desertification - Heavily populated arid regions are most vulnerable - Cooking produces indoor air pollution • New biomass sources are being developed • Biopower = biomass sources are burned in power plants - Generating heat and electricity • Biofuels = liquid fuels used to power automobiles © 2011 Pearson Education, Inc.
33.
Biopower generates electricity Many
types of biomass are combusted to generate electricity • Waste products of industries or processes - Woody debris, crop residues • Specifically grown crops (fastgrowing willow trees, bamboo) • Co-firing combines biomass and coal • Gasification turn biomass to steam • Pyrolysis produces a liquid fuel © 2011 Pearson Education, Inc.
34.
Scales of production •
Farmers, ranchers, or villages use manure, wood waste, or biogas from digestion to generate electricity - Small household biodigesters work in remote areas • The U.S. has dozens of biomass-fueled power plants • Biomass power increases efficiency and recycling - It reduces CO2 emissions and dependence on imported fossil fuels - It is better for health and supports rural economies • But burning crops deprives the soil of nutrients - Relying only on bioenergy is not a sustainable option © 2011 Pearson Education, Inc.
35.
Ethanol can power
automobiles • Ethanol = a biofuel made by fermenting carbohydrate-rich crops - Ethanol is added to U.S. gasoline to reduce emissions • In 2009, 10 billion gallons were made in the U.S. from corn • Congressional mandates will increase ethanol production © 2011 Pearson Education, Inc.
36.
Cars can run
on ethanol • Flexible-fuel vehicles run on E-85 - 85% ethanol, 15% gasoline - 8 million cars are in the U.S. - Most gas stations do not yet offer this fuel • Bagasse = crushed sugarcane residue used to make ethanol - 50% of new Brazilian cars are flexible-fuel vehicles © 2011 Pearson Education, Inc.
37.
Ethanol may not
be sustainable • Environmental scientists don’t like corn-based ethanol • Growing corn impacts ecosystems - Pesticides, fertilizers, irrigation - Takes up land that could be left unfarmed • Ethanol competes with food and drives up food prices - As farmers shifted to ethanol, corn for food dropped - Mexicans could not afford tortillas, and so they rioted • Growing corn requires energy for equipment, pesticides, and fertilizers • Its EROI ratio is about 1.5:1, so it is inefficient © 2011 Pearson Education, Inc.
38.
Biodiesel powers engines •
Biodiesel = produced from vegetable oil, cooking grease, or animal fats • Vehicles can run on 100% biodiesel - B20 = 20% biodiesel • Biodiesel reduces emissions • Its fuel economy is good • It costs a bit more than gasoline • Crops are specially grown - Using land, deforestation © 2011 Pearson Education, Inc.
39.
Novel biofuels are
being developed • Algae produce lipids that can be converted to biodiesel - Their carbohydrates can be fermented to make ethanol • It can be grown in ponds, tanks, or photobioreactors • Algae grows fast and can be harvested every few days - It can use wastewater, ocean or saline water - It can capture CO2 emissions to speed its growth • Biofuels from algae are currently expensive • Cellulosic ethanol = produced from structural plant material (e.g., corn stalks) that has no food value - Switchgrass provides ethanol, habitat, and high EROI © 2011 Pearson Education, Inc.
40.
Two novel biofuels Algae
is a candidate for a next-generation biofuel Switchgrass provides fuel now and may provide cellulosic ethanol © 2011 Pearson Education, Inc.
41.
Is bioenergy carbon-neutral? •
In principle, biomass energy releases no net carbon - Photosynthesis removes carbon that is released when biomass is burned • Burning biomass is not carbon-neutral: - If forests are destroyed to plant bioenergy crops - If we use fossil fuel energy (tractors, fertilizers, etc.) • The Kyoto Protocol gives incentives to destroy forests for biofuel crops - Only emissions from energy use (not land-use changes) are “counted” toward controlling emissions © 2011 Pearson Education, Inc.
42.
Hydroelectric power (hydropower) •
Hydropower = uses the kinetic energy of moving water to turn turbines to generate electricity • Storage technique = water stored in reservoirs behind dams passes through the dam and turns turbines • Run-of-river approach generates electricity without disrupting the river’s flow - Flow water over a small dam that does not impede fish passage - Useful in areas away from electric grids © 2011 Pearson Education, Inc.
43.
A typical dam ©
2011 Pearson Education, Inc.
44.
A run-of-river system ©
2011 Pearson Education, Inc.
45.
Hydroelectric power is
widely used • Hydropower accounts for 2.2% of the world’s energy supply - And 15.6% of the world’s electricity production • Nations with large rivers and economic resources have used dams • However, many countries have dammed their large rivers - People want some rivers left undammed • The U.S. government built dams to employ people and help end the economic depression of the 1930s - Engineers exported their dam-building techniques © 2011 Pearson Education, Inc.
46.
Hydropower is clean
and renewable • Hydropower has two clear advantages over fossil fuels for producing electricity: - It is renewable: as long as precipitation fills rivers we can use water to turn turbines - It is clean: no carbon dioxide is emitted • Hydropower is efficient - It has an EROI of 10:1 - As high as any modern-day energy source © 2011 Pearson Education, Inc.
47.
Hydropower has negative
impacts • Damming rivers destroys wildlife habitats - Upstream areas are submerged - Downstream areas are starved of water • Natural flooding cycles are disrupted - Downstream floodplains don’t get nutrients • Downstream water is shallower and warmer • Periodic flushes of cold reservoir water can kill fish • Dams block passage of fish, fragmenting the river and reducing biodiversity • Large dams can cause earthquakes or collapse © 2011 Pearson Education, Inc.
48.
Hydropower may not
expand much more • China’s Three Gorges Dam is the world’s largest dam - It displaced 1 million people - Generates as much electricity as dozens of coal-fired or nuclear plants • Most of the world’s large rivers have already been dammed • People have grown aware of the ecological impact of dams and resist more construction • Developing nations with rivers will increase hydropower © 2011 Pearson Education, Inc.
49.
Conclusion • With limited
fossil fuel supplies, nations are trying to diversify their energy portfolios • Nuclear power showed promise - But high costs and public fears stalled its growth • Biomass energy sources include wood and newer biofuels - They can be carbon-neutral but are not strictly renewable • Hydropower is a renewable, pollution-free alternative - But it is nearing maximal use and can involve substantial ecological impacts © 2011 Pearson Education, Inc.
50.
QUESTION: Review Conventional alternative
fuels: a) Exert less environmental impact than fossil fuels but are currently not feasible b) Are intermediate sources of fuel that can help us on our path towards sustainability c) Are final sources of fuel that will give us energy independence d) Are no longer available for widespread use © 2011 Pearson Education, Inc.
51.
QUESTION: Review The reaction
that drives the release of energy in today’s nuclear power plants is: a) b) c) d) Nuclear fission Nuclear fusion Control rods Nuclear emergencies © 2011 Pearson Education, Inc.
52.
QUESTION: Review Why have
nuclear power plants not been popular in the United States? a) b) c) d) Fears about accidents or sabotage Storage of nuclear waste is still not solved High costs of building and maintaining plants All are issues regarding nuclear energy © 2011 Pearson Education, Inc.
53.
QUESTION: Review Ethanol in
the United States is made mainly from ______, and is used to ______. a) b) c) d) Soybeans, heat homes Sugarcane, drive cars Corn, drive cars Willow trees, make electricity © 2011 Pearson Education, Inc.
54.
QUESTION: Review Which of
the following is an interesting future biofuel? a) b) c) d) Corn Algae Nuclear Shale oil © 2011 Pearson Education, Inc.
55.
QUESTION: Review Which of
the following forms of hydropower is least environmentally destructive? a) b) c) d) The storage approach Run-of-river approach Bend-of-river approach All of these are destructive forms and none should be used. © 2011 Pearson Education, Inc.
56.
QUESTION: Weighing the
Issues Given the choice of living next to a coal-burning power plant or nuclear plant, which would you choose? a) The nuclear plant, because it’s cleaner. b) The coal plant, because it won’t be as likely a target for terrorists. c) Neither one; I’d move to another place. d) Either one; I don’t care. © 2011 Pearson Education, Inc.
57.
QUESTION: Interpreting Graphs
and Data If ethanol in the United States continues to be produced from corn, a drawback suggested from this graph could be: a) More corn is available for ethanol. b) More competition between food and fuel. c) Less land planted in corn. d) None of these. © 2011 Pearson Education, Inc.
Descargar ahora