Energy, Society, and the EnvironmentUnit 9

TRANSPORTATION and ENERGY

Outline

• Vehicle-Fuel link is strong

• The Demands for Transportation are strong and increasing

• Petroleum use has many problems: Dictatorships, sovereignty, pollution, greenhouse gases

• But the fossil fuel supplies are large for the time being

• Policy and technology needed

World Oil Use

020406080

100120140160180

1990 2000 2010 2020 2030 2040 2050

million barrels per day

Transportation All Other

Source: World Oil Worksheet (WOW) Model, USDOE/OTT

Liquid Fuels

Transportation Sector Key to Energy Use

• Transportation accounts for ~1/3 of energy use

• When electricity generation factored out, transportation dominates

• Demand projected to increase• 97% of transportation energy from

petroleum• Relatively small number of technologies

employed• Transportation sector energy use can

impact national security and environmental impacts 0

10

20

30

40

50

1950 1960 1970 1980 1990 2000 2010

Percentage

Year

Commercial

Residential

Industrial

Transportation

b)

Performance actually decliningU.S. Light Duty Vehicles

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

1975 1980 1985 1990 1995 2000 2005 2010Model Year

MPG

HP

Weight

0-60

Source: EPA (2006)

CAFE: corporate average fuel economy

Source: Brandt and Farrell (2006)

Getting the oil out … to the last drop

C o n f i n i n g S t r a t a

H e a v y O i l

T a r S a n d s

S h a l e O i l

C o a l

H e a t

W a v eL i g h t O i l

I n - S i t u R e f i n i n gR e f i n e r y

T h e r m a l C r a c k e r

L i g h t O i l

H e a v y

O i l

H e a t e r

P e t r o c o k e

H e a t e r

W e l l

P r o d u c t i o n

W e l l

S e q u e s t e r e d

C a r b o n

Fischer-Tropsch Production

• Fischer-Tropsch. In addition to traditional refinery technologies, there is one other technology that is used to produce liquid fuels: Fischer-Tropsch synthesis.

• The Fischer-Tropsch process can convert any high-carbon stream ultimately to liquid fuels at significant environmental costs.

• It is the process used today in several countries to convert coal and natural gas to liquid fuels.

Vehicle Ownership and GDP/Capita

0100200300400500600700

5000 10000 15000 20000 25000

GDP per Capita

vehicles per 1000 capita

U.S. Japan France U.K.

World Vehicle Projections

• By 2050, 3.0 - 4.0 BILLION vehicles in the world (depending on population growth, economic growth, consumer habits)

Where does a car’s gasoline go?

• 6% accelerates the car, <1% moves the driver

• Three-fourths of the fuel use is weight-related

• Because of efficiency, each unit of energy saved at the wheels saves ~7–8 units of gasoline in the tank (or ~3–4 with a hybrid)

• So, first make the car dramatically lighter!

But Small cars are unsafe, right??

But Small cars are unsafe, right??

Addressing Transportation

• Efficiency is Job #1

• Bring U.S. vehicle efficiency standards to world standards

Addressing Transportation

• Efficiency is Job #1

• Bring U.S. vehicle efficiency standards to world standards

• Promote the use of goal-appropriate vehicle use

Efficiency is not the entire answer

• Efficiency is not a source of energy, “fuels” will still be needed.

QuickTime™ and a decompressor

are needed to see this picture.

Available Options and Criteria

• Fossil Fuel ICEs, Hybrid electric cars, Plug-in Hybrid Electric Cars, Electric Cars, Biofuels, Hydrogen

• Criteria: Vehicle Technology, Supply Infrastructure, Resource Base, Environment

Plug-in Hybrid Electric Vehicle (PHEV)Combustion engine and stored electric energy both usedAdaptation of existing hybrids

Range-Extended Electric Vehicle (REEV)Drive power is primarily electricEngine is used only when stored electrical energy is exhausted

Battery Electric Vehicle (BEV)Use on on-board electricityRecharged from electrical gridNo engine

Hybrid Electric Vehicle (HEV)Combustion engine plus one or more electric motors. Uses only hydrocarbon fuel

Slide Credit: Dr. Mark DuvallElectric Power Research Institute

EV and PHEV

• Environment

• Infrastructure

• Resource base

• Vehicle Technology

Power Plant-Specific PHEV Emissions in 2010PHEV 20 – 12,000 Annual Miles

Slide Credit: Dr. Mark DuvallElectric Power Research Institute

EV and PHEV

• Environment:

• Infrastructure:

• Resource base: (but keep in mind problems with overall energy demand)

• Vehicle Technology: ?

Batteries

QuickTime™ and a decompressor

are needed to see this picture.

An electrochemical energy storage device

chemical energy --> electrical energy (and back during recharging)

QuickTime™ and a decompressor

are needed to see this picture.

EV and PHEV

• Environment:

• Infrastructure:

• Resource base: (but keep in mind problems with overall energy demand)

• Vehicle Technology: ? Getting there.

Hydrogen Fuel Cellsfrom the Arizona Daily Wildcat

DaimlerChrysler “F-Cell” Vehicle DaimlerChrysler “F-Cell” Vehicle

Hydrogen

• The lightest element

• Abundant on Earth but not found in free form

• Most commonly found as H2O (water molecule) and CH4 (methane) and a variety of other hydrocarbons.

• Hydrogen must, therefore, be produced from these molecules by expending energy. It can then be stored as H gas.

Producing Hydrogen

• Steam reforming: from methane with very high temperature steam

CH4 + H2O → CO + 3 H2

• Electrolysis: passing electric current through water to separate it into O2 and H2.

Hydrogen stores energy

• Steam reforming and electrolysis use energy: so why do it?

• Hydrogen can be stored and then recombined with oxygen and release energy.

• Hydrogen is not a primary energy source; it stores energy similar to the way a battery does.

Question: Why are hydrocarbons (e.g., methane, petroleum…) primary energy sources but not hydrogen?

Efficiency

• Is hydrogen an efficient energy storage mechanism?

Losses in production,storage, recombination

Energy density

Energy Density

need to compress hydrogen (by A LOT!) or liquefy it to make it transportable

Storage

• Optimal hydrogen storage system would have high energy density Optimal hydrogen storage system would have high energy density (by weight and volume), low cost, quick refueling, and good safety(by weight and volume), low cost, quick refueling, and good safety

• Major candidates are:Major candidates are: - compressed gas (~ 700 bar)- compressed gas (~ 700 bar) - cold liquid (cryogenic storage)- cold liquid (cryogenic storage)

Compressed gas requires steel tanks that can withstand pressure (very Compressed gas requires steel tanks that can withstand pressure (very heavy) or expensive materials such as carbon nanotubes, polymers heavy) or expensive materials such as carbon nanotubes, polymers

Liquid hydrogen requires cryogenic tanks Liquid hydrogen requires cryogenic tanks

In either case, hydrogen storage density is ~1% by weightIn either case, hydrogen storage density is ~1% by weightNo realistic chemical storage is currently available No realistic chemical storage is currently available

How do you use hydrogen?

• Fuel Cell:

reverse electrolysis

Recombine it with oxygen to produce energy and water

Efficiency

• Efficiencies multiply

• For example, if half the energy lost in step 1 and half of the remaining is lost in step 2, overall efficiency is

= 1/2 x 1/2 = 1/4 (25 %)

For hydrogen fuel cells:

Overall “well-to-wheel” efficiency = electrolysis efficiency x compression efficiency x recombining efficiency in fuel cell

= 70% x 80 % x 60% = 34 % (optimistic)

Comparison to EVs

Hydrogen Fueling Infrastructure

Hydrogen Energy Station in Hydrogen Energy Station in Las Vegas, NevadaLas Vegas, Nevada

Many challenges remain

for hydrogen fuel cell vehicles

Term Paper II

• You will need to use turnitin.com to submit it.

• Class ID: 2698159

• Class Password: energy

• You need to create a user profile asap. Go to turnitin.com and click New User. Then, under New Students, click on Create a User Profile.

• Bring printed copy to class on Friday.

• This information is also available on D2L.

Announcements 4/20

• Assignment #8 is posted on D2L.

It is due Monday April 27.

BIOFUELS

Plants high in sugar:Sugarcane, sugar beet,starch

Fermentation Bioalcohols

Plants high in oil:Oil palm, soybean, algae

Heat, purify Burn in diesel engine

Cellulosic ethanol from Non-edible plants

Convert to sugar with Enzymes, ferment

Bioalcohols

Many pathways exist for liquid, gas, solid fuels

Limiting Factors

• Energetic favorability

• Land use

• Economical factors

• Technology

Algae Biofuels

“PetroSun has announced it will begin operation of its commercial algae-to-biofuels facility on April 1st, 2008. The facility, located in Rio Hondo Texas, will produce an estimated 4.4 million gallons of algal oil and 110 million lbs. of biomass per year off a series of saltwater ponds spanning 1,100 acres. Twenty of those acres will be reserved for the experimental production of a renewable JP8 jet-fuel.” (gas2.org)

NPR’s Science Friday this past week had a discussion on algae biofuels: http://www.sciencefriday.com/program/archives/200904171