Chapter 12Nonrenewable Energy

Resources

Energy use has consequences

1969 - coast of Santa Barbara CA- 3 million gallons of oil Prompted creation of the first Earth Day: April 22, 1970

1989: Exxon Valdez, Alaska - 53 million gallons. 2010: BP Deepwater Horizon -Gulf of Mexico -206

million gallons of oil – 11 killed 2005: BP oil refinery in Texas. 15 workers killed. 2010: Coal mine explosion -West Virginia. 29

miners killed.

Discovery, drilling, extraction, pipelines, transportation, refining, use, disposal All cause pollution, environmental degradation, &

human health effects Many of these externalities are not included in

price Especially for fossil fuels

Most of our Energy

Most of our energy comes from nonrenewable sources that once they are used up, they

cannot be replenished). Two main categories: Fossil fuels and Nuclear

fuels. What affects the rate at which energy is

used? Availability Affordability More recently, environmental impacts. In 2005, U.S. used 5x the world avg Overall, 20% of the world - developed countries

use 70% of the energy!

Energy UseBy

Resource

World Annual Energy consumption

More than 80% of our energyComes from fossil fuels

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.

Energy Use

Energy History

Pre-Industrial – muscles and firewood

Industrial – burning wood, then coal

Post-industrial – burning a variety of fossil fuels with a variety of renewables

The U.S. produces 70% of the energy it needs. 30% from other countries.

Energy use varies both seasonally and regionally. Air conditioning/heating needs. The type of energy used is a function of many

factors: ease of transport, amount of energy per mass of fuel

Energy Efficiency

Second law of thermodynamics: as a source of energy is transformed its ability to do work diminishes - Heat is lost during conversion at every step

incandescent light bulb: 5%

internal combustion engine: 15%

nuclear power plant: 30%

coal burning power plant: 35%

photosynthesis : 1%

Electricity is clean at the point of use but there are many pollution tradeoffs before that point.

Greatest efficiency comes with the fuel that entails the fewest conversions from the original source.

EROEI: Energy return on energy investment)

Energy obtained from the fuel

Energy invested to obtain the fuel

**The bigger the EROEI, the better.

Fuels like oil from tar sands require a great deal of energy to extract and refine – lowering their value

EROEI =

Transportation efficiency Public transportation is much more efficient. Car

efficiency goes up as more people are added. Recent legislation says that by 2016, the overall fleet

average MPG must be at 35. (CAFE standards)

Mostly from coal

U.S. Electricity Generation

Making Electricity: flow of electrons

1. Burn a fuel source (wood, coal, nuclear)2. Use heat to produce steam3. Steam (or flowing water or wind) turns turbines

creating a flow of electrons in the generator4. Electricity is distributed

Creating Electricity Commercial electricity is made by the turning of

magnets or electromagnets inside casings of coiled copper wired.

The magnets are connected to a turbine which is turned by the force of steam, water or wind flowing past it.

Heat source

Turbine

Wire coils

Magnets

Transformer

Cogeneration- using a fuel to generate electricity and to produce heat.

Example- If steam is used for industrial purposes or to heat buildings it is diverted to turn a turbine first.

This improves the efficiency to as high as 90%.

Cogeneration

Fossil fuel comparisons

C O A L

What is coal? Coal is fossilized plant material that was subjected

to heat and pressure over millions of years. The largest coal reserves are in the United

States, Russia, China, Major use: electricity generation

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Coal- a solid fuel formed primarily from the remains of trees, ferns, and other plant materials that were preserved 280-360 million years ago.

Four types of coal ranked from lesser to greater age, exposure to pressure, and energy content: lignite, sub-bituminous, bituminous, and

anthracite.

Types of Coal Anthracite: Rare, but high quality coal with high energy

content; cleanest burning coal Bituminous: Plentiful type of coal with high energy

content, but higher sulfur concentrations Subbituminous: Lower heat value, but cleaner burning

(less sulfur) Lignite: also called brown coal. Lowest heat value.

Youngest coal. Peat: coal precursor made of partially decomposed

organic material

Fig. 16-12, p. 368

Increasing heat and carbon content

Increasing moisture content

Peat (not a coal)

Lignite (brown coal)

Bituminous

(soft coal)

Anthracite

(hard coal)Heat Heat Heat

Pressure Pressure Pressure

Partially decayed plant matter in swamps and bogs; low heat content

Low heat content; low sulfur content; limited supplies in most areas

Extensively used as a fuel because of its high heat content and large supplies; normally has a high sulfur content

Highly desirable fuel because of its high heat content and low sulfur content; supplies are limited in most areas

Environmental Impacts of coal burning

SOx, NOx and CO2 production Acid deposition from high sulfur content Release of other air pollutants including

particulates, mercury, arsenic, and lead Releases radioactive particles In China, home coal burning exposes families

to toxic metals including arsenic and mercury Mining:

Acid mine drainage Habitat loss Loss of human lives

Mining for Coal:Habitat destruction (low rate of successful restoration despite 1977 SMCRA law)Erosion & LandslidesAirborne dust hazardsTailings can pollute waterways

Advantages and Disadvantages

Pros Most abundant fossil

fuel Major U.S. reserves 200 years. at current

consumption rates High net energy yield Infrastructure in place

Cons Dirtiest fuel, highest

carbon dioxide Major environmental

degradation from mining: air pollution and acid rain Major threat to human

health Trace metals like

mercury, lead, and arsenic released

Particulate matter Ash Sulfur Oxides = acid rain

Petroleum- a mixture of hydrocarbons, water, and sulfur that occurs in underground deposits.

Formed from the remains of ocean-dwelling phytoplankton that died 50-150 million years ago.

Main use: Transportation - gasoline & diesel fuel for vehicles

Countries with the most petroleum are Saudi Arabia, Venezuela, Canada, Iraq, Iran, Russia

Petroleum

Petroleum

Sources of Oil Organization of Petroleum Exporting Countries (OPEC)

-- 12 countries control 80% of global oil supplies

Fractional Distillation

Separates out components of crude oil by boiling point.

Lighter compounds will boil first and rise.

U.S. Oil Supplies

The U.S. – the world’s largest oil user – 2% of world’s reserves

U.S oil production peaked in 1974 (halfway production point).

About 60% of U.S oil imports goes through refineries in hurricane-prone regions of the Gulf Coast.

Unconventional Oil

Much of the easy oil is gone; increasingly difficult and destructive sources are used now Deepwater Drilling Tar Sands Oil Shales

Petroleum- a mixture of hydrocarbons, water, and sulfur that occurs in underground deposits.

Formed from the remains of ocean-dwelling phytoplankton that died 50-150 million years ago.

Oil and gasoline make this ideal for mobile combustion, such as vehicles.

Countries with the most petroleum are Saudi Arabia, Russia, the United States, Iran, China, Canada, and Mexico.

Petroleum

Heavy Oils: Tar Sands & Oil Shale: Heavy and tarlike oils from oil sand and oil shale

could supplement conventional oil, but there are environmental problems. High sulfur content. Extracting and processing produces:

Toxic sludge Uses and contaminates larges volumes of water Requires large inputs of natural gas which

reduces net energy yield.

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 Deliberate and accidental releases of waste oil

Possible that it might melt permafrost and interfere with the calving of caribou along pipelines

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

Advantages and Disadvantages of

Petroleum

Natural Gas

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Natural Gas - Fossil Fuel Mixture

80 -95% Methane (CH4) Other gases: Ethane (C2H6), Propane (C3H8),

Butane (C4H10), Hydrogen sulfide (H2S) – TOXIC Formed same way as petroleum (heat and

pressure) Mined by pumping it out of the ground Largest uses are for electricity generation and

industrial processes in the U.S. Also used for residential heating, clothes

dryers, stoves, water heaters.

Natural Gas Reserves

Conventional Natural Gas Found above crude oil reserves Formed by the same process A natural gas pipeline must be built in oil

reserves, otherwise the resource is lost Unconventional Natural Gas

Methane hydrates – trapped in ice crystals below the permafrost/ocean sediments

how to get it out?

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Sources of Natural Gas

Russia & Iran - almost 44% of world's supply.

Qatar (13%), Saudi Arabia (4.6%), Algeria (4%), United States (5%), Nigeria (3%), Venezuela (3%);

FrackingProcess:

1. Locate oil/gas and drill a well up to 10,000 ft deep

2. High Pressure Injection: pump in fluid (water, chemicals, sand)

3. Rock surrounding the well cracks or fractures

4. Oil/gas is released through cracks, travels back up well, and is collected above ground

Injection fluid

Oil/gas

Oil/gas

fractures

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Locations in the USA

Locations Worldwide

Domestic product Makes US less dependent on foreign

energy Provides 30% of domestic energy

1.2 million jobs in US Saves money

Revives old wells Enables reuse of equipment

Profits for site landowners Natural gas produces less air

pollution and less CO2 than coal or oil

Buys time to develop the technology for alternative energy Pros

Air and Water pollution Contaminated water from injection fluid - stored in open

pits Groundwater pollution: Methane = flammable water Air pollution: VOCs and Nox lead to smog, GHGs to global

warming Requires huge quantities of water (1-8 million gallons per

fracking operation Chemicals in Injection Fluid

600 different chemicals, many are carcinogens Benzene, Formaldehyde

Human health hazards Neurological disorders, Cancer, Birth defects

Habitat fragmentation Initially exempt from Clean Air Act and Safe Drinking

Water Act (new rules now passed) May contribute to earthquakes

QuickTime™ and a decompressor

are needed to see this picture.

Cons

Cons

Fracking: waste water wells& earthquakes from 2011 to 2015

Advantages Disadvantages

Contains fewer impurities and therefore emits almost no sulfur dioxide or particulates

When unburned, methane escapes into the atmosphere (potent greenhouse gas)

Emits only 60% as much carbon dioxide as coal

Exploration of natural gas has the potential of contaminating groundwater

Large quantities of water used during extraction

Advantages and Disadvantages

Natural Gas

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. He predicted in 1969 that 80% of world reserves would be used up within 60 years.

The Hubbert Curve

If current global use continues, we will run out of conventional oil in less than 40 years.

Coal supplies will last for at least 200 years, and probably much longer.

Technological advances in renewable energy will someday make oil less desirable.

The Future of Fossil Fuel Use

Nuclear Energy

Often rejected because of concerns over the dangers of nuclear accidents, radioactivity, and weapons.

Fission- a nuclear reaction in which a neutron strikes a relatively large atomic nucleus, which then splits into two or more parts.

Nuclear Energy

Nuclear Reactors

Uses the same basic principles to create electricity as the coal plant except that a fission reaction (of U-235) provides the heat.

Fuel rods- the cylindrical tubes that house the nuclear fuel used in a nuclear power plant.

Nuclear power plants work by using heat from nuclear fission to heat water. This water produces the steam to turn the turbine, which turns a generator.

Control rods- cylindrical devices that can be inserted between the fuel rods to absorb excess neutrons, thus slowing or stopping the fission reaction.

Nuclear Reactors

Nuclear ore

Large commercial uranium mining operations exist in Australia, Western U.S., and parts of Canada.

70% of the electricity generated in France comes from nuclear and it has wide use in Lithuania, Germany, Spain, the UK, Japan, China and South Korea.

The U.S. gets 20% of their electricity from nuclear. Currently 104 plants in the U.S.

Fig. 16-19, p. 376

Trade-Offs

Conventional Nuclear Fuel Cycle

Advantages Disadvantages

Large fuel supply Cannot compete economically without huge government subsidies

Low environmental impact (without accidents) Low net energy yield

High environmental impact (with major accidents)Emits 1/6 as much CO2 as coal

Catastrophic accidents can happen (Chernobyl)

Moderate land disruption and water pollution (without accidents)

No widely acceptable solution for long-term storage of radioactive wastes and decommissioning worn-out plantsModerate land use

Low risk of accidents because of multiple safety systems (except for 15 Chernobyl-type reactors)

Subject to terrorist attacks

Spreads knowledge and technology for building nuclear weapons

High-level radioactive waste- the form used in fuel rods.

Low-level radioactive waste- the protective clothing, tools, rags, and other items used in routine plant maintenance.

Uranium mine tailings- residue left after uranium is mined and enriched.

Radioactive Waste

Radioactive waste- once the nuclear fuel can not produce enough heat to be used in a power plant but it continues to emit radioactivity.

This waste must be stored in special, highly secure locations because of the danger to living organisms. Cannot be incinerated, disposed of using

chemicals, shot into space, dumped on the ocean floor.

Remains a threat for 10 half-lives (the accepted number by scientists).

Radioactive Waste

Where to store waste???

1982 Nuclear Waste Policy Act (NWPA)

Federal Government's responsibility

Recommendation: Storage/disposal of high level radioactive waste - stable geologic repository deep underground

Current disposal: (Not recommended) on location of nuclear power plants – where produced

Yucca Mountain

In 1978 the U.S. department of Energy began examining the Yucca Mountain site in Nevada as a permanent storage area. In 2002, Congress approved Yucca

Mountain to serve as the long-term storage facility for all nuclear waste in the U.S.

n 2006 the DOE released a report confirming the soundness of the site.

In 2011, Project was defunded.

Nuclear fusion- the reaction that powers the Sun and other stars. This occurs when lighter nuclei are forced together to produce heavier nuclei and heat is released.

Fusion is a promising, unlimited source of energy in the future, but so far scientists have had difficulty cotaining the heat that is produced.

Fusion