Chapter 12

Nonrenewable Energy Resources

All Energy Use Has Consequences• Oil :

– Jan 1969 - Oil well explosion and rupture - off coast of Santa Barbara, CA – 1989 – Exxon Valdez (was largest until 2010) in Prince William Sound, Alaska– 2005 – explosion at BP oil refinery (TX)– April 2010 – BP Deepwater Horizon oil spill in Gulf of Mexico– Combustion of fossil fuels (gasoline, jet fuel, diesel) emit pollutions

environmental harm• Coal:

– April 2010 - explosion at Upper Big Branch Mine (West Virginia) coal mine– Coal miners develop black lung disease and other respiratory ailments

• Natural Gas:– Considered to be the “clean” fossil fuel– Extraction difficult

• So what’s the problem? - we are depended on fossil fuels for energy supply

Deepwater Horizon Oil Spill April 20, 2010

• Aka: BP oil spill• Oil flowed unabated for 89 days• Cause: explosion on platform– Methane gas explosion– Efforts by multiple ships to douse the flames were

unsuccessful • Burned for approximately 36 hours

– Why problem? • July 15, 2010: the leak was stopped capped

the gushing wellhead – Estimated 206 million gallons of crude oil released

Deepwater Horizon Oil Spill• September 19, 2010: the relief well process was successfully

completed• November 2010: 4,200 square miles of the Gulf were re-closed to

shrimping after tar balls found in shrimpers' nets• January 2011: oil spill commissioner reported that problems still

exist• February 2011 : researchers found tar on the bottom of the

seafloor did not seem to be degrading• July 9, 2011: roughly 491 miles of coastline in LA, MS, AL and FL

remained contaminated• January 2011 :the White House oil spill commission released its

final report on the causes of the oil spill. • September 2011: U.S. government published its final investigative

report on the accident.

Deepwater Horizon Oil Spill

• Extensive damage to: – marine and wildlife habitats – Gulf's fishing and tourism industries

• To remove oil/protect beaches, wetlands, estuaries:– skimmer ships– floating containment booms– anchored barriers– sand-filled barricades along shorelines– dispersants

http://ecopolitology.org/2010/06/08/cutaway-of-deepwater-horizon-oil-spill-response-graphic/

Nonrenewable Energy• Nonrenewable energy resources – 2 categories:– Fossil fuels (coal, oil, natural gas)

• Combustion - burn the fuels– Nuclear fuels

• Radioactive materials• Units of energy– J – joule

• EJ (exajoule) = 1 x 109 gigajoules– Quad – not used in US

• 1 quad = 1.055 EF– Btu – British thermal unit

• 1 Btu = 1 055.06 J

Worldwide Patterns of Energy Use

• Each country uses energy at different rates– Uses different energy resources

• 2008 – total world energy was about 495 EJ

Energy Use• Energy not distributed equally

around world• WHY?• Terminology – Commercial energy sources- those

that are bought and sold, such as coal, oil and natural gas

– Subsistence energy sources- those gathered by individuals for their own use such as wood, charcoal and animal waste

Patterns of Energy Use in US

• Many changes since 1850s – due to political, economical, and environmental factors

• Main energy sources (in order) – oil, coal, natural gas

• Energy use varies regionally and seasonally

Process of Energy Use• Energy efficiency,

includes: – Efficiency of the process

of obtaining the fuel – Efficiency of process that

coverts it to work that is needed

• Many opportunities for energy loss reduces energy efficiency

• EROEI (energy return on energy investment) EROEI = Energy obtained from fuel Energy invested to get fuel

Efficiency and Transportation

• ~30% of energy in US is used for transportation

• Transportation – movement of people and goods

• Public transportation more efficient than car

• Transportation efficiency – does not take into account convenience, comfort or style

• Overall fuel efficiency of US personal vehicle fleet – has improved

Electricity Generation

• Primary source of energy – coal, oil, natural gas• Secondary source of energy – electricity

Energy Efficiency• Most coal burning

power plants are about 35% efficient

• Combined cycle natural gas-fired power plant – ~60% efficient

• Capacity – maximum electrical output

• Capacity factor – the fraction of the time a plant can operate in a year

Cogeneration

• Using a fuel to generate electricity and to produce heat– Aka – combined heat and power

• Improves the efficiency to as high as 90%

Fossil fuels provide most of the world’s energy…

• Fossil fuels – coal, oil and natural gas• Come from deposits of organic matter formed

50-350 million years ago– In anaerobic environment (lack of O2)

• Fossil fuels are carbon sinks

Coal• A solid fuel formed primarily from the remains of trees, ferns, and

other plant materials – Preserved 280-360 million years ago– Ideal fuel for power plants and industry

• Four types of coal ranked from lesser to greater age, exposure to pressure, and energy content:– Lignite – softest coal– Subbituminous coal– Bituminous coal – most common type– Anthracite – highest grade of coal

• Peat – precursor to coal – Composed of partly decomposed organic matter (including mosses)

• Largest coal reserves – United States, Russia, China, and India.

Coal

Advantages and Disadvantages of Coal

Advantages Disadvantages

Energy-dense Contains impurities (ie. sulfur)

Plentiful Release impurities into air when burned

Easy to exploit by surface mining Trace metals like mercury, lead, and arsenic are found in coal

Technological demands are small Combustion leads to increased levels of sulfur dioxide and other air pollutants into the atmosphere.

Economic costs are low Ash is left behind

Easy to handle and transport Carbon is released into the atmosphere which contributes to climate change

Needs little refining

Petroleum

• Mixture of hydrocarbons, water, and sulfur – Remains of ocean-dwelling phytoplankton - died 50-

150 million years ago• Crude oil – liquid petroleum removed from

ground– Can be broken down into

• US uses petroleum more than any other fuel for:– Gasoline – about ½ of the petroleum we use– Raw materials for…

• Most petroleum – Saudi Arabia, Russia, the United States, Iran, China, Canada, and Mexico

Petroleum

Advantages and Disadvantages of Petroleum

Advantages Disadvantages

Convenient to transport and use Releases carbon dioxide into atmosphere

Relatively energy-dense Possibility of leaks when extracted and transported

Cleaner-burning than coal Fragile ecosystems

Releases sulfur, mercury, lead, and arsenic into the atmosphere when burned

Natural Gas

• Natural gas- exists as a component of petroleum in the ground as well as in gaseous deposits separate from petroleum– Original source …– Contains 80 to 95 percent methane and 5 to 20

percent ethane, propane, and butane• Uses in US: • Compressed natural gas – fuel for vehicles• Liquefied petroleum gas – in lieu of natural gas,

portable barbecue grills and heaters

Advantages and Disadvantages Natural Gas

Advantages Disadvantages

Cheap fuel source for homes

Contains fewer impurities emits almost no sulfur dioxide or particulates

Unburned methane escapes into the atmosphere

Emits only 60% as much carbon dioxide as coal

Exploration of natural gas has the potential of contaminating groundwater

Other Fossil Fuels:Oil Sands

• Not readily available• Oil sands- slow-flowing, viscous deposits of bitumen

mixed with sand, water, and clay– Bitumen (tar or pitch)- a degraded type of petroleum that

forms when a petroleum migrates close to the surface (lack of nonporous rock cap), where bacteria metabolize some of the light hydrocarbons and others evaporate

– Benefits- extends petroleum supply– Negative environmental impacts-

Other Fossil Fuels:Liquefied Coal

• CTL – coal-to-liquid– Converts soil coal to liquid fuel– Technology has been around for decades– Benefits:

– Downsides:

Fossil fuels are a finite resource

• Energy intensity – energy use per unit of gross domestic product– Energy used

more efficiently but• More people • More energy

used

The Hubbert Curve

• Hubbert curve- a graph that shows the point at which world oil production would reach a maximum and the point at which we would run out of oil

• Peak oil – point at which ½ of total known oil supply is used up– *1969 – Hubbert

predicted 80% of world’s oil would be used up in ~60 years

The Future of Fossil Fuel Use

• How long will our fossil fuels last? - If current global use continues, we will run out of:– Conventional oil – Natural gas – Coal supplies

• Some factors influencing use of fossil fuels:– More concern about global warming – Rising costs of fossil fuels

NUCLEAR ENERGY FUEL-URANIUM…

Another conventional, nonrenewable fuel that does not significantly add to greenhouse gases in atmosphere.

Nuclear Energy• Fission- a nuclear reaction

in which a neutron strikes a relatively large atomic nucleus, which then splits into two or more parts– Chain reaction – Releases an immense

amount of heat– Fuel – U-235 common – Byproducts – radioactive

waste

Nuclear Reactors

Advantages and Disadvantages of Nuclear Energy

Advantages Disadvantages

No air pollution is produced Possibility of accidents

Countries can limit their need for imported oil

Disposal of the radioactive waste

Fukushima, Japan• 6 reactors affected• Loss of power = reactors overheated• Full meltdown of 3 reactors– Attempt to use seawater ruined reactors

• Other concerns:– Water levels in fuel rod pools decreased

• Total radioactivity released was ~1/10 of Chernobyl– Most at risk – workers– Recommendations for infants?

http://www.google.com/url?sa=i&rct=j&q=fukushima+japan+nuclear&source=images&cd=&cad=rja&docid=gy8_kFhsD5DqQM&tbnid=sTiE6rwKUJLYSM:&ved=&url=http%3A%2F%2Frbth.ru%2Farticles%2F2011%2F03%2F15%2Frussian_experts_assess_japans_nuclear_situation_12559.html&ei=9-ZrUdb1M4XE0QGN6oAw&bvm=bv.45175338,d.dmQ&psig=AFQjCNGWHrm8oAegNpsPuxkzcQ41a6X65Q&ust=1366112376058134

Since…• Pale grass blue butterflies• 2 months after (sample 144)

– ~12% of butterflies affected• 6 months after (sample 258)

– ~28% of butterflies affected• http://worldnews.nbcnews.c

om/_news/2012/08/14/13274288-study-japan-nuclear-disaster-caused-mutated-butterflies?lite

Radioactive Waste

• Radioactive waste – nuclear fuel that can no longer produce enough heat to be useful in a power plant but continues to emit radioactivity

• 3 types: – High-level radioactive waste – Low-level radioactive waste – Uranium mine tailings

Radioactive WasteMeasuring Radiation

• Units:– Becquerel (Bq) • 1 Bq = the decay

of one atom per second

– Curie • 1 curie =37 billion

decays per second

Radioactive Wastes• Spent fuel rods remain threat for 10 or more ½

lives long term storage is important– All spent fuel rods must be stored at the plant

• Long term solution to waste– Possibilities

• Above ground mausoleums• Arctic ice sheets• Beneath ocean floor• Send to space

– Standards for LTS:– So what was thought up… Yucca Mountain burial

Radioactive WasteYucca Mountain, NV• 1978 – started

looking at location • Lots of protest/

controversy• 2006 –considered

safe storage location• Few years late

cancelled

Stuff to add from old textbook:Decommissioning Nuclear Power Plants

• Licensed to operate for 40 years– Several have received 20-year extensions

• Power plants cannot be abandoned when they are shut down

• Three solutions– Storage– Entombment– Decommissioning (dismantling)

Fusion

• Nuclear fusion- occurs when lighter nuclei are forced together to produce heavier nuclei – Heat is released– Most promising reaction

• Promising, unlimited source of energy in the future– Input – hydrogen

• Problem – creating fusion requires reactor can heat material to 10x the temperature of the Sun’s core– Promising technique

Look at Table

12.2 in your

book!