Announcements – April 13, 2010

Exam 2 one week from today (Wednesday April 20)

Energy Sources II

Lecture Objectives:

1) Understand the breakdown of fossil fuel usage in the U.S.

2) Learn about pros and cons of alternative energy sources

3) Understand the benefits and risks of nuclear energy

4) Learn easy ways to conserve fossil fuel use

How do we consume fossil fuels in the U.S.?

85.7% of total energyPetroleum (39.2%)

Transportation 67%Electrical Power 3%Industrial 24%Residential/Commercial 6%

Natural Gas (23.7%) Total by AreaTransportation 0.1% Transportation 26.3%Electrical Power 35% Electrical Power 30.1%Industrial 43.6% Industrial 21.8%Residential/Commercial 21.2% Residential/commercial 7.5%

Coal (22.8%)Transportation NAElectrical Power 90.5%Industrial 9%Residential/Commercial 0.5%

Source: www.eia.doe.gov

One Problem with fossil fuels

~86% of energy in U.S. currently supplied by non-renewable resources, which will run out at some point in the future!!!

Solution?

Develop alternative sources of energy, preferably from renewable resources.

Hydroelectric Power

2.5% of world’s commercial energy (2.7% U.S.)

River water is held behind a dam

Falling water is used to spin the turbine to generate electricity

Environmental Impacts of Hydroelectric Power

Reservoir construction causes significant environmental and social damage.

•Loss of farmland

•Community relocation

•Reduction of nutrient-rich silt leading to loss of wetlands.

•Changes to the hydrology of the river

•Impacts aquatic animals

The Three Gorges Dam

Started in 1997

Stretches 1.3 miles across the Yangtze River

The Three Gorges Dam

Reasons for constructing:•Power Generation•Increased ability for navigation•Flood control•Reduce dependence on coal

Environmental and Social Impacts:•Endangered Wildlife (Chinese alligator, river dolphin)•Massive relocation of people•Flooded archeological sites and scenic canyons

Wind

U.S. Dept. of Energy rated wind power the world’s fastest growing energy source in the 1990s. (but currently supplies <0.1% of U.S. energy needs

Cost for electricity generation becoming competitive with fossil fuel sources.

Steady, dependable wind source is critical

Environmental Impacts of Wind Power

Can be hazardous to birds

Produces noise

Considered “visual pollution” by some

Solar Energy

Daily energy from the sun is 600X greater than energy produced by all other energy sources combined.

Major problem as an energy source is its intermittent nature. Beverly, Massachusetts photovoltaic (PV) array

Three Major Use Categories

• Passive Heating — Sun’s energy is converted directly to heat and used at collection site.

• Active Heating — Sun’s energy is converted into heat, but transported elsewhere to be used.

• Electrical Generation — Solar energy is transformed into electrical energy.

Photovoltaic Cells

Unit that allows direct conversion of sunlight to electricity.

Developed in 1954 by Bell Laboratories essentially as a novelty.

By mid 1980s, more than 60 million solar calculators produced annually.

Limitations of Solar Energy

Large PV arrays require space

Works only during the day

Inadequate in cloudy climates.

Inadequate in many colder climates as sole heating source (need conventional back-up)

Currently provides less than 1% of world’s energy

Fuelwood

In less-developed countries, fuelwood has been major energy source for centuries.

Fuelwood is primary energy source for nearly half world’s population.

Estimated 1.3 billion people cannot get enough, or are using it faster than rate of regeneration.

Source of air pollution and fly ash

Not really a viable alternative energy source for US

Less common sources:

Tidal Power – tides can be used to spin an electricity-generating turbine

limited applicability

La Rance Tidal Power Station

Tidal Power Generation.The Annapolis Tidal Generating Station is a pilot project to explore the potential of harnessing energy from the sea. Annapolis Tidal utilizes the sea water of the Bay of Fundy. Tides, which can sometimes reach 21 feet in height, rise and fall every 12 hours and 25 minutes in harmony with the gravitational forces of the Sun, the Earth, and the Moon.

Lake Source Coolinghttp://www.utilities.cornell.edu/LSC/default.htm

Cornell University Ithaca, NY

Uses cold water from Cayuga Lake to cool University Buildings

80% energy savings over conventional chillers

Lake Source Coolinghttp://www.utilities.cornell.edu/LSC/default.htm

History of Nuclear Development

First controlled fission—Germany 1938.

1945—U.S. dropped atomic bombs on Hiroshima and Nagasaki.

U.S. built world’s first nuclear power plant in 1951

Currently, 8.4% of U.S. energy from nuclear power

Nuclear Power Plants in North America

IllinoisNumber of nuclear units: 11 Braidwood 1-2, Braidwood, Ill.Byron 1-2, Byron, Ill.Clinton, Clinton, Ill.Dresden 2-3, Morris, Ill.LaSalle 1-2, Seneca, Ill.

Quad Cities 1-2, Cordova, Ill.

Workings of A Nuclear Reactor

Generates electricity

Chain reaction produces heat

Converts water to steam

Turns a turbine

Nuclear Reactor — Device that permits a controlled fission chain reaction.

Nuclear Fuel Cycle

• As fission occurs, U235 concentration in fuel rods decreases.

• After about 3 years, fuel rods don’t have enough radioactive material left to sustain a chain reaction

• Spent fuel rods are replaced by new ones.– What to do with the spent fuel rods?

Environmental Impacts of Nuclear Power

• More than 330 underground storage tanks currently exist with high-level radioactive waste.

• 5,700 sites have wastes moving through soil.

• Clean up will take years and cost tens of billions of dollars.

– Environmental clean up single largest item in DOE budget.

Nuclear Wastes

U.S. DOE Waste Sites

Radioactive Waste Disposal

• High Level:– At this time, NO country has a permanent

storage solution for high-level waste.

– Politics of disposal are as crucial as disposal method.

– Waste Isolation Pilot Plant (WIPP) Carlsbad, NM began accepting waste in March, 1999.

Environmental Impacts of Nuclear Power

High-Level Waste• In 1982, Congress called for a high-

level radioactive disposal site to be selected by 1987, and to be completed by 1998.

• Final Site Selection Occurred in 1989.– Yucca Mountain, Nevada

Not to be completed before 2015. By that time, waste produced

by nuclear power plants will exceed the storage capacity of the site.

Low-Level Waste

Currently, U.S. produces about 800,000 m3 of low-level radioactive waste annually.

Presently buried in various scattered disposal sites.

Includes cooling water from nuclear reactors, material from decommissioned reactors, protective clothing, etc.

Prior to 1970, U.S. alone placed 50,000 barrels of low-level radioactive waste on the ocean floor. Banned in 1983.

Nuclear Power Concerns• Currently, 17% of

electricity consumed worldwide comes from nuclear power.

Contamination and disposal problems.

Accidents raised questions about safety.

Life expectancy of reactors originally only 20 years, now extended to 40-60 years

•Three Mile Island—PA

March 28, 1979—Partial Core Melt-Down.

Pump and valve malfunctionCompounded by false readout and operator error

No Deaths

Very Little Radiation Vented

Public Relations Disaster

Chernobyl—Ukraine –April 26, 1986

Chernobyl — Ukraine

Experiments were being conducted on one reactor

Reactor Explodes

Numerous safety violations

Chernobyl—Ukraine

Increases in Thyroid cancer rate by 10x

31 deaths

116,000 people evacuated

24,000 evacuees received high doses of radiation

Fallout in Scandinavia and Europe

Japanese Declare Crisis at Level of Chernobyl April 11, 2011

The Japanese government raised its assessment of the month long crisis at its Fukushima Daiichi nuclear power plant to the highest severity level by international standards—a rating only conferred so far upon the Chernobyl accident (which struck almost exactly 25 years ago, on April 26, 1986.).

Japan's nuclear regulators said the plant has likely released so much radiation into the environment that it must boost the accident's severity rating on the International Nuclear Event scale to a 7 from 5 currently.

Japanese Declare Crisis at Level of Chernobyl April 11, 2011

Japanese officials went to lengths to say that the problem they are struggling to contain isn't anywhere near the disaster of Chernobyl.

"First, the amount of released radiation is about a tenth of Chernobyl," he said, adding that while there were 29 deaths resulting from short-term exposure to high doses of radiation at Chernobyl, there were no such deaths at Fukushima.

"At Chernobyl, the nuclear reactor itself exploded," he said, adding that at the Fukushima plant, the pressure vessel and the containment vessel were largely intact.

http://nextbigfuture.com/2011/03/deaths-per-twh-by-energy-source.html

A comment on these alternative sources:

Source Energy producedHydroelectric ElectricityWind ElectricitySolar Electricity, Direct HeatingTidal ElectricityLake Source CoolingNuclear Electricity

But current fossil fuel use is:Transportation 26.3%Electricity 30.1%Industrial 21.8%Residential/Commercial 7.5%

Can we decrease use of fossil fuels for transportation and industrial fuel use?

>95% of Transportation energy supplied by petroleum

“In transportation uses, in contrast, there is little fuel substitution possible in the short term and only limited potential in the longer term, given current technology” – Oil Market Basics, www.eia.doe.gov

Vast majority of automobiles & trucks run on gasoline or diesel

Major infrastructure of gas stations not easily converted to other fuels

Buenos Aires, ArgentinaOver 200,000 taxis use natural gas as fuel.

2009 profit: $19.3 billion

The global recession cost Exxon bragging rights: It's no longer America's largest company ( that title now goes to Wal-Mart) and it isn't posting record profits. Indeed, earnings got cut in half as sales dropped by more than a third in 2009.

But Exxon remains unlike any company on our list. Consider that the oil giant spent a record $27 billion during the year on exploration projects, yet it still earned more than the gross domestic product of Macedonia.

Alternatives to gas-powered autosElectric

limited range, lack of power stations

Hybrid electricgreatly increased MPG, becoming more popular

Still uses gas, can use existing infrastructure

Methanol/Ethanol (biofuels)Biomass conversion (organic wastes, crops)

Still uses gas; food shortages, more habitat loss?

Fuel cellsonly produces water, heat, electricity

takes more energy to produce

BMW sets 9 records with Hydrogen Combustion Engine. Top Speed over 300 km/h

A fundamental consideration is that the combustion properties of hydrogen are quite different from those of gasoline or diesel: While hydrogen burns faster than conventional fuels under normal air pressure, the combustion temperature is slightly lower than in the case of gasoline.

Hydrogen cars…. Only waste is water!

But, where will we get pure hydrogen (H2)?- still need to burn fossil fuels to produce H2!

Biofuels: Green energy or grim reaper?22 September 2006, Jeff McNeeley

“Biofuels could end up damaging the natural world rather than saving it from global warming. Better policies, better science and genetic modification call contribute to a greener biofuels revolution.”

Biofuels = “deforestation diesel”??

It is a renewable energy resource if pursued properly.

Ethanol burns more cleanly than oil.

Can be made from a wide variety of “crops”

Arguments for biofuels

Grain required to fill an SUV with ethanol could feed one person for one year.

Much of plant material imported from Brazil where deforestation continues.

Ethanol from maize in U.S. require fossil fuels at every stage in production process.

cultivation, fertilizers, tractors, processing, transportation

Up to 30% more energy spent than gained.

Arguments against biofuels

Other options?

Conservation!!!

Most current energy use is highly inefficient– Lobbying against regulated increases in automobile

efficiency (MPG)– Little development of mass transit and railroad

transportation– Most construction done with “cheaper,” energy inefficient

materials– Industrial machines and practices are energy inefficient

$$ given as reason, but are we/they really saving money in the long run??

What you can (easily) do conserve energy:

1) Replace incandescent light bulbs with fluorescent.

2) Make sure car tires at proper air pressure and use recommended grade of gas.

3) Consider biking, walking, carpooling, taking bus or train.

4) Buy energy efficient appliances, insulate house, replace windows.

5) Consider buying hybrid electric vehicle or one with higher MPG.

Points to know

1) Why is there controversy surrounding drilling in ANWR? What are the issues?

2) Know the major uses of oil, natural gas, and coal. What current proportion of energy in the U.S. is supplied by fossil fuels, and how does that break down by area?

3) Know the pros and cons of hydroelectric, wind, solar, and nuclear power.

4) What is the main problem with most alternative sources of energy in regards to lowering our dependence on fossil fuels?

5) Why it is more difficult to use alternative energy sources for transportation? What alternatives are there?

6) What are some easy ways to conserve energy?