Energy Resources

Geothermal Energy: A Free Lunch?Environmental Problems

of Geothermal Energy• It is Finite • Heat Sources Can Be

Exhausted (Geysers, California)

• Sulfur Emissions• Disposal of Mineralized

Brines

Technical Problems of Geothermal Energy

• Corrosion• Mineral Deposition in

Pipes• Non-Productive gases

(Carbon dioxide, methane, etc.)

• Low Temperatures • Low Thermodynamic

Efficiency

Thermodynamic Efficiency

Thermodynamic Efficiency

• Eff. = (Ti - Tf)/Ti

• T = Degrees Kelvin = Degrees C + 273• Ti = initial temperature• Tf = final temperature

Thermodynamic Efficiency

Automobile Engine• Ti = 1200 C = 1473 K • Tf = 500 C = 773 K • Eff = (1473 - 773)/1473 = 48%

Typical Steam Power Plant• Ti = 700 C = 973 K • Tf = 200 C = 473 K • Eff = (973 - 473)/973 = 51%

Thermodynamic Efficiency

Geothermal Power Plant• Ti = 150 C = 423 K • Tf = 80 C = 353 • Eff = (423 - 353)/423 = 17%Actual achieved efficiencies• Automobile on Highway: about 5% • Geothermal Plant: 5% or So, Sometimes

less than 1%

Nuke-u-lar Energy• U-235 fissions to lighter nuclei• Naturally 0.7% in uranium ore• Must be enriched to 3-4% for reactors• Mining is conventional metal mining• Radium (decay product) is principal

problem in mine wastes

Radiation Hazards• Problem in the body is ionization and creation of

free radicals• Alpha particles (He nuclei) have +2 charge– Do not penetrate skin– Worst ionization problem if ingested

• Beta particles (Electrons)– Weak penetration ability– Moderate ionization problem

• Gamma Rays (High Energy photons)– Great Penetrating ability– Lowest ionization ability

Plutonium• Produced in small amounts in civilian

reactors• Toxicity of Plutonium is a Myth– Chemically it is comparable to U, Th– Ra and Rn are worse radiation hazards– Chemical plus Radiation hazard high

• Main Problem: Long-lived waste product• Security issue: Can be Chemically Separated

from Uranium

Nuclear Waste• Contain until radiation decays to negligible

levels (Pu = 24,000 years)• Possible Containment Schemes– Yucca Mountain– Crystalline Rock– Salt Domes– Subduction Zones?– Space?

• Breeder Reactors?– Security Concerns

Fossil Fuels

Coal Seams, Utah

Coal

• Delta, continental environments– Autochthonous: Grew in Place– Allochthonous: Transported Log Mats

• Carbonized Woody Material• Often fossilized trees, leaves present

Plant Fragments Are Often Visible in Coal

Coal Forms From Wood

Petroleum

A hydrocarbon molecule

What organisms make these?Answer: None

Petroleum

• Lots of organisms make these, however

• Fatty Acids• Probable source: Marine plankton

Hydrocarbons CnH2n+2

Name Formula Melts C Boils C

Methane CH4 -182 -164

Ethane C2H6 -183 -88

Propane C3H8 -190 -42

Butane C4H10 -138 0

Pentane C5H12 -130 36

Hexane C6H14 -95 69

Octane C8H18 -57 126

Decane C10H22 -28 174

Eicosane C20H42 37 343

Triacontane C30H62 66 450

Hydrocarbons• Methane = Natural Gas• Propane-Butane = Bottled Gas• Iso-octane (2,2,4 Trimethylpentane) = Gasoline• Cetane (Hexadecane = C16 H34) = Diesel Fuel

• Kerosene = 12-15 Carbons• Mineral oil, petroleum jelly, paraffin wax = 20-40

Carbons• Bitumen (Asphalt) ~ 50 Carbons

Iso-Octane (Gasoline)

Abiogenic Petroleum?• 18Mg2SiO4 + 6Fe2SiO4 + 26H2O + CO2 →

12Mg3Si2O5(OH)4 + 4Fe3O4 + CH4

• Olivine + Water → Serpentine + Magnetite + Methane

• nCH4 + nFe3O4 + nH2O → C2H6 + Fe2O3 + HCO3 + H+

• Methane + Magnetite → Ethane + Hematite• Minority view in Russia• Resurgence among U.S. Right Wing

Petroleum-Bearing Rocks, Utah

Petroleum Traps

Seismic Reflection Profile

MethaneHydrate

Gas Hydrates

• Hydrocarbons trapped in cage of water molecules

• Freeze above 0 C under moderate pressure• Solid gas hydrates occur in marine

sediments (“yellow ice”)• Potentially huge energy resource• Possible role in climate change?

Energy Use, California, 1972

Energy Use, California, 1979

Energy Use, California, 1993

Energy Use, California, 1994

Energy Use, California, 2003

All You Need to Know

Economics• 2000 WINNEBAGO CHIEFTAIN

SERIES M-36LP-DSL• Average Retail Price: $51,600 • Suggested List: $140,851• Source: NADAGuides.com (23 April 2010)• Ten-Year Cost: $89,251• @$300/day = 297 days = 30 days/year

Planning for the future has long-term benefits

Procrastination pays off Now

An Oil Drilling Bit

“World’s Richest Acre”

Offshore Oil Rig

Offshore Oil Rig

Offshore Oil Rig

Deep-Water Oil Rig

(Houston for Scale)

Anchor Link for Deep Water Rig

Ocean Star, Galveston, Texas

Cutaway of Drill Bit

Soft Rock Bits

Derrick

Pipe Grappler

Drilling Floor

“Christmas Tree”

“Christmas Tree”

Well Completion

Rocker

Oil Recovery

• Primary: Natural Pressure Forces Oil to Surface– Recovery Rate 5 – 15%

• Secondary: Pumping and Pressurized Fluids– Total After Secondary Recovery: 35-45%

• Tertiary: Solvents, Steam, Carbon Dioxide– Total After Tertiary Recovery: 50-60%

• No Underground Resource Recovery Gets All of the Resource

Where Does The Oil Go?

Oil Refinery

Where the Oil Is

The Geography of Oil

Why So Much Oil?

Hubbert Curves

• In 1956, Oil geologist M. King Hubbert noted that rates of oil production follow a bell-shaped curve.

• Cumulative production follows a slanting S- curve• Production lags discovery by about ten years.

Hubbert’s 1956 Prediction

Where We Stand Today

What if We Find More Oil?

• Even a huge increase in total oil has very little effect on the peak and decline of production.

• Why? We waste most of it on inefficient uses.

One Solution: Limit Production

Is There a Lot More Undiscovered Oil?• 80 per cent of oil being produced today is from fields

discovered before 1973. • In the 1990's oil discoveries averaged about seven

billion barrels of oil a year, only one third of usage.• The discovery rate of multi-billion barrel fields has

been declining since the 1940's, that of giant (500-million barrel) fields since the 1960's.

• In 1938, fields with more than 10 million barrels made up 19% of all new discoveries, but by 1948 the proportion had dropped to only 3%.

Oil Discovery Rates

U.S. Petroleum Use• 2009 - 7,121,644,500 barrels• 2007 - 6,257,125,000 barrels• 2006 - 6,384,780,000 barrels• 2005 - 6,470,457,000 barrels• 2004 - 6,410,770,000 barrels• 2003 - 6,175,244,000 barrels• 2002 - 5,945,585,000 barrels• = 19,498,000 barrels a day• = 1 billion barrels in < two months

Global Petroleum Usage• 2008 projection: 87 million barrels/day• = 31.8 billion barrels per year• = 1 billion barrels in 11.5 days• = 1000 barrels/second• U.S. = 25% of total

Oil Fantasies“America is sitting on top of a super massive 200 billion barrel Oil Field that could potentially make America Energy Independent and until now has largely gone unnoticed. Thanks to new technology the Bakken Formation in North Dakota could boost America’s Oil reserves by an incredible 10 times, giving western economies the trump card against OPEC’s short squeeze on oil supply and making Iranian and Venezuelan threats of disrupted supply irrelevant” (Next Energy News, 13 February 2008)

Realty Check• 200 billion barrels @ 20 million barrels a

day = 10,000 days = 27 years• Then what?• Reality: maybe 10% of the oil is recoverable

with known technology• The Bakken is a “tight” formation• Horizontal drilling can increase yields

Canadian Oil Sands • 170 billion recoverable barrels• 10 x larger total amount• Current production: 1.2 million barrels/day• Projected production in 2015 = 3 million

barrels per day• 3 million barrels = 4 hours of U.S.

petroleum consumption

Some Relevant Quotes

The internal-combustion engine used for automobiles is a fragile device compared with other prime movers -- even compared with the internal combustion engines used for diesel- electric locomotives that have been known to go over a million miles without mechanical overhauling.

Some Relevant Quotes

... the energy-system efficiency of the motor car with petroleum motor fuel is, thus, 5 percent ... no one is proud of this accomplishment -- least of all the automotive-design engineers ... The trouble is, every time the design engineer manages to save a few BTU it is more than spent answering the clamor for softer tires, for radio, for better heaters, more lights, cigarette lighters and possibly even air conditioning.

Some Relevant Quotes

Histories written a few centuries hence may describe the United States as a nation of such extraordinary technologic virility that we succeeded in finding ways of dissipating our natural wealth far more rapidly than any other nation. At any rate, we are having a wonderful time doing it. From the discussions in the earlier chapters of this book it is clear that the problem of energy for the United States is not one of the dim future. It is upon us now.

Some Relevant Quotes

Our imports of petroleum are small but each year they become larger. By 1960 they are likely to be quite substantial. By 1970 they will almost certainly be huge -- if foreign oil is still available then in sufficient quantity... This tiny period of earth's life, when we are consuming its stored riches, is nearly over ... Fortunately for us there is still time for fundamental research [on alternative energy sources]. But not too much time.

Some Relevant Quotes: Source

Eugene Ayres and Charles A Scarlott, 1952; Energy Sources -- The Wealth of the World, McGraw-Hill, 344p.

Petroleum is a Syllogism

• There is a finite amount of it in the world• We are using it and not replacing it• Therefore we will eventually run

out of it• Any of this not clear?

The End of Cheap Oil

• Known petroleum can last at least a couple of centuries more, but…

• It only flows through the rocks so fast.• No amount of drilling will make it flow faster,

and careless drilling can shorten the lifetime of an oil field.

• Sometime in the 21st century, global demand will outpace production capacity and…

• Oil will go to the highest bidder.