Alternative Fuels Used in Transportation: Science Projects in Renewable Energy and Energy Efficiency

U.S. DEPARTMENT OF

Energy Efficiency &

ENERGY EDUCATION AND WORKFORCE DEVELOPMENT

Renewable Energy

ENERGY

Alternative Fuels Used in

Transportation

Grades: 5-8

Topic: Hydrogen and Fuel Cells, Vehicles, Biomass

Owner: National Renewable Energy Laboratory

This educational material is brought to you by the U.S. Department of Energy’s

Office of Energy Efficiency and Renewable Energy.

This lesson plan may contain links to other resources,

including suggestions as to where to purchase materials.

These links, product descriptions, and prices may change over time.

lternative Fuels Used in Trans

ortation

For the Teacher:

The use of energy is a factor in all our

lives, and that is why it is important for

us teachers to have our students learn

about the energy we use now and the

new forms of energy that are becoming

available. Non-renewable energy

sources are diminishing everyday, and it

is vital that students learn about

renewable energy sources to help them

as they grow to become better informed

and more responsible about the energy

resources they use.

The use of gasoline for

transportation is the most commonly

used fuel. However, there are multiple

alternative fuels that are making their

ways to the market. These alternative

fuels include such things as propane,

natural gas, electric hybrids, hydrogen

fuel cells, and biodiesel. Students will

probably have heard of some of these

alternative fuels, but they may not

understand how and why they are

better then ordinary gasoline. The

projects included in this section are

designed to give students the

opportunity to create their own

investigation and test alternative fuels

and their relation to transportation.

The projects included will fit

easily with regular classroom lessons

surrounding scientific inquiry and the

scientific method. The projects have

of the capability to cross multiple

education disciplines such as chemistry,

physics, economics, and marketing and

they involve social interaction as well as

group learning.

Alternative fuels are being

researched by top scientists every day

at NREL to discover which fuel methods

work best, how well they work and how

easily they can be distributed to the

public. The authors of this section are

studying the emissions released from

large trucks running on different

biodiesel fuels to compare which blends

create lower emissions.

National Science Education

Standards by the National Academy

of Sciences:

Science Content Standards: 5-8

Science as Inquiry

- Content Standard A:

“Abilities necessary to do scientific

inquiry”

“Understandings about scientific

inquiry”

Physical Science

- Content Standard B:

“Properties and changes of

properties in matter”

“Transfer of energy”

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Earth and Space Science

- Content Standard D:

“Structure of the earth system”

Science and Technology

- Content Standard E:

“Abilities of technological design”

“Understandings about science and

technology”

Science in Personal and Social

Perspectives

- Content Standard F:

“Populations, resources, and

environments”

“Science and technology in society”

Technolo

y Description:

Transportation by cars and trucks

radically changed the face of our

country over the last hundred years,

with petroleum providing the fuel for

our vehicles. We use about 13 million

barrels of oil each day to keep us on the

move. Americans drive their personal

vehicles about 2.3 trillion miles a year

with 98 percent of our vehicles running

on petroleum or diesel fuels. United

States imports two-thirds of all the

petroleum we use; therefore, cheaper

and renewable alternative fuels would

be desirable to reduce our dependence.

In addition to the dependence factor,

one also needs to consider that the

emissions from gasoline-powered

vehicles are fairly extensive and include

CO, CO

, NOx, SOx, VOCs, OH

, and PM.

Some of these emissions are known or

probable human carcinogens, including

benzene (known), formaldehyde,

acetaldehyde, and 1,3-butadiene

(probable). Gasoline can also impact the

environment if spilled, since it spreads

on water surfaces and quickly

penetrates porous soils and

groundwater.

The idea of alternative fuels has

been around about as long as there

been vehicles. In the 1880s, Henry

Ford built one of his first automobiles to

run on ethanol. The alternative fuels

that are being actively explored by the

Department of Energy include:

methanol; propane; ethanol;

compressed and liquefied natural gas;

electricity; hybrid electricity; biodiesel;

and hydrogen fuel cells. Factors such as

cost, fuel distribution, emissions, vehicle

systems analysis, energy storage, power

and propulsion systems, and advanced

power electronics are just some of the

considerations in phasing in alternative

fuels and advanced vehicle design.

Complete Combustion

Fuel (hydrocarbons) + Air (O

& N)

⇒ CO

+ H

O + N

Typical Engine Combustion

Fuel + Air Unburned Hydrocarbons

+ NO

+ CO + CO

+ H

Improving fuel economy, cost,

availability, and emissions are the

primary goals of research into

alternative fuels and transportation.

Alternative Fuels-

Methanol

Methanol, or wood alcohol, is a

colorless, odorless, toxic liquid.

Methanol is the simplest alcohol

(CH

OH), produced by replacing one

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hydrogen atom of methane with a

hydroxyl radical (OH). Methanol can be

produced from natural gas, coal,

residual oil, or biomass.

Although vehicles can operate on pure

methanol fuel (M100), methanol

blended with 15 percent unleaded

gasoline–M85- is more practical for real

world applications. Because methanol is

a liquid fuel, it does not require major

changes in the distribution system or in

car engines, but no major auto

manufacturers offer M85 compatible

vehicles at this time. The cost of M85 is

equal to or slightly higher than premium

blends. M85 has a lower energy

content per gallon, so mileage is lower;

but power, acceleration and payload

capacity are comparable to gasoline.

Vehicles using methanol, however, must

use a special, expensive lubricant.

Propane

Propane is an energy-rich fossil fuel

often called liquefied petroleum gas

(LPG). It is colorless and odorless; an

odorant called mercaptan is added to

serve as a warning agent. Propane is a

by-product of petroleum refining and

natural gas processing. And, like all

fossil fuels, it is nonrenewable. The

chemical formula for propane is C

Under normal atmospheric

pressure and temperature, propane is a

gas. Under moderate pressure and/or

lower temperature, however, propane

can easily be changed into a liquid and

stored in pressurized tanks. Propane is

270 times more compact in its liquid

state than it is as a gas, making it a

portable fuel.

Propane has been used as a

transportation fuel for more than half a

century and is the most widely used and

most accessible alternative fuel. Today

about three percent of total propane

consumption is used to fuel 270,000

vehicles, mostly in fleets. For fleet

vehicles, the cost of using propane is 5

to 30 percent less than for gasoline.

Ethanol

Ethanol is a clear, colorless

alcohol fuel made by fermenting the

sugars found in grains—such as corn

and wheat—as well as potato wastes,

cheese whey, corn fiber, rice straw,

urban wastes, and yard clippings. There

are several processes that can produce

alcohol (ethanol) from biomass. The

most commonly used processes today

use yeast to ferment the sugars and

starch in the feedstock to produce

ethanol. A new process uses enzymes

to break down the cellulose in woody

fibers, making it possible to produce

ethanol from trees, grasses, and crop

residues.

In the 1970s, the oil embargoes

revived interest in ethanol as an

alternative fuel. Today, more than fifty

ethanol plants, mostly in the Midwest,

produce over a billion gallons of ethanol.

Gasoline containing ten percent

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ethanol—E10—is widely used in urban

areas that fail to meet standards for

carbon monoxide and ozone. Since

ethanol contains oxygen, using it as a

fuel additive results in up to 25 percent

fewer carbon monoxide emissions than

conventional gasoline. E10 is not

considered an alternative fuel under

EPACT, but a replacement fuel.

Methane

Methane, the natural gas we use

for heating, cooking, clothes drying, and

water heating, can also be a clean

burning transportation fuel when

compressed (CNG) or liquefied (LNG).

Compressed natural gas (CNG) vehicles

emit 85-90 percent less carbon

monoxide, 10-20 percent less carbon

dioxide, and 90 percent fewer reactive

non-methane hydrocarbons than

gasoline-powered vehicles. (Reactive

hydrocarbon emissions produce ozone,

one of the components of smog that

causes respiratory problems.) These

favorable emission characteristics result

because natural gas is 25 percent

hydrogen by weight; the only

combustion product of hydrogen is

water vapor. Natural gas is usually

placed in pressurized tanks when used

as a transportation fuel. Even

compressed to 2,400-3,600 pounds per

square inch (psi), it still has only about

one-third as much energy per gallon as

gasoline. As a result, natural gas

vehicles typically have a shorter range,

unless additional fuel tanks are added,

which can reduce payload capacity. With

an octane rating of 120+, power,

acceleration and cruise speed are

comparable.

Electricity

In 1891, William Morrison of Des

Moines, Iowa, developed the first

electric car. By the turn of the century,

dedicated electric vehicles (EVs)

outnumbered their gasoline-powered

counterparts by two-to-one. Today

there are about 10,500 dedicated EVs in

use in the United States, mostly in the

West and South. Researchers are still

working on the same problem that

plagued those early dedicated EVs: the

need for an efficient battery. The

batteries limit the range of a dedicated

EV, which is determined by the amount

of energy stored in its battery pack. The

more batteries a dedicated EV can carry,

the more range it can attain, to a point.

Too many batteries can weigh down a

vehicle, reducing its load-carrying

capacity and range, and causing it to

use more energy. The typical dedicated

EV can only travel 50 to 130 miles

between charges. This driving range

assumes perfect driving conditions and

vehicle maintenance. Weather

conditions, terrain, and some

accessories use can significantly reduce

the range.

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Hybrid Electricity

Hybrid Electric Vehicles (HEVs) may be

the best alternative vehicle for the near

future, especially for the individual

consumer. HEVs offer many of the

energy and environmental advantages

of the dedicated electric vehicle without

the drawbacks. Hybrids are powered by

two energy sources: an energy

conversion unit (such as a combustion

engine or fuel cell) and an energy

storage device (such as battery,

flywheel, or ultracapacitor). The energy

conversion unit can be powered by

gasoline, methanol, compressed natural

gas, hydrogen, or other alternative

fuels. HEVs have the potential to be

two to three times more fuel-efficient

than conventional vehicles. An HEV

battery doesn’t have to be recharged. It

has a generator powered by the internal

combustion engine to recharge the

batteries whenever they are low. A

regenerative braking system captures

excess energy when the brakes are

engaged. The recovered energy is also

used to recharge the batteries.

Gas-Electric Hybrids

Biodiesel

Biodiesel is a fuel made by

chemically reacting alcohol with

vegetable oils, fats, or greases, such as

recycled restaurant greases. It is most

often used in blends of two percent or

20 percent (B20) biodiesel. It can also

be used as neat biodiesel (B100).

Biodiesel fuels are compatible with and

can be used in unmodified diesel

engines with the existing fueling

infrastructure. It is the fastest growing

alternative transportation fuel in the

U.S. Biodiesel contains virtually no

sulfur, so it can reduce sulfur levels in

the nation’s diesel fuel supply.

Removing sulfur from petroleum-based

diesel results in poor lubrication.

Biodiesel is a superior lubricant and can

restore the lubricity of diesel fuel in

blends of only one or two percent.

Biodiesel can also improve the smell or

diesel fuel, sometimes smelling like

french fries.

Berkeley Curbside Recycling Trucks Now Fueled

by Recycled Vegetable Oil

Hydrogen Fuel Cell

In the future, hydrogen may

provide a significant contribution to the

alternative fuel mix. The space shuttles

use hydrogen for fuel. Fuel cells use

hydrogen and oxygen to produce

electricity without harmful emissions;

water is the main by-product. Hydrogen

is a gas at normal temperatures and

pressures, which presents greater

transportation and storage hurdles than

liquid fuels. No distribution system

currently exists. Today, the

predominant method of producing

hydrogen is steam reforming of natural

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gas, although biomass and coal can also

be used as feedstocks.

SunLine Transit Agency

Hydrogen Fuel Cell Bus

Resources:

Energy Efficiency and Renewable Energy

http://www.fueleconomy.gov/

National Energy Educational

Development

http://www.need.org

Energy Efficiency and Renewable Energy

http://www.eere.energy.gov

Kentucky Clean Fuels Coalition

www.kentuckycleanfuels.org

U.S. Environmental Protection Agency

www.epa.gov

National Renewable Energy Laboratory -

Department of Energy

www.nrel.gov

Alternate Transportation Fuels

http://www.need.org/needpdf/Alternativ

eFuels.pdf

Energy Correlation to National Science

Education Content Standards

http://www.need.org/needpdf/Correlatio

ns.pdf

Pro

ect Ideas

1 What is the heat content of

two alternative fuels?

Learning Objective: You will be able

to measure the amount of heat

absorbed by water during the

combustion of methanol and ethanol in

a calorimeter.

Controls and Variables: Volume of

water, temperature change in heat sink

(100 ml of water), mass of fuel used,

and heat content of two fuels.

Materials and Equipment: Economy

calorimeter; alcohol burners; ethanol;

methanol; & thermometers.

Safety and Environmental

Requirements: Safety glasses should

be worn at all times. The frame of the

economy calorimeter retains heats and

care must be taken when moving after

testing.

Suggestions:

• Determine the number of chemical

bonds in methanol (5) and ethanol

(8).

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• Correlate the heat content of each

fuel related to the number of

chemical bonds.

• Students explore why the obtained

heat values fall below the actual heat

values (ethanol = 7089 cal/g and

methanol = 5426 cal/g).

• Do a balance of equations for the

combustion of methanol

(2CH

OH + 3 O

⇒ 2CO

+ 4H

O +

energy) and ethanol (C

OH + 3 O

⇒ 2CO

+ 4H

O + energy).

• Determine the oxygen to fuel ratio

for each fuel and how this ratio

would change the volume of carbon

dioxide produced.

Places To Purchase:

Calorimeter:

https://www1.fishersci.com/wps/portal/

HOME

($25.60, economy food calorimeter)

https://www.freyscientific.com

($21.95, economy food calorimeter)

A homemade calorimeter can be

made by using two different size cans

with holes through the top of both cans

to suspend the smaller can over the

flame with glass stir rod. The larger can

is a tube and the smaller can opens only

on top, to hold water and take

temperature readings (Note diagram

below).

Wickless Leakproof Burner

https://www1.fishersci.com/wps/portal/

HOME

($14.00, holds 100cc of fuel)

https://www.freyscientific.com

($13.65, holds 100cc of fuel)

Flint Glass Alcohol Lamp

https://www.freyscientific.com

($6.25, 8 oz. capacity)

https://www1.fishersci.com/wps/portal/

HOME

($6.35, 8 oz. capacity)

Ethanol

https://www1.fishersci.com/wps/portal/

HOME

($10.80, 1 liter)

https://www.freyscientific.com

($8.35, 1 liter)

Methanol

https://www1.fishersci.com/wps/portal/

HOME

($5.15, 500 ml)

https://www.freyscientific.com

($6.65, 500 ml)

2 What is the economically

best choice between

purchasing a hybrid or a

typical gasoline engine

automobile?

Learning Objective: You will be able

to show which type of engine is the

most economical in the long run

between a hybrid and typical gasoline

engine.

222

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Controls and Variables: The different

variables for each automobile will be the

initial cost, the operating cost (gasoline

price), and the miles per gallon of fuel.

Constants should be the amount of

driving that would be done in each

automobile.

Materials and Equipment: Pen, paper

and access to the Internet for research.

Safety and Environmental

Requirements: None

Suggestions:

• The payback period is the length of

time you must own an energy-

efficient vehicle before the decreased

operational costs make up for the

difference in initial purchase price.

Calculate the payback period for a

Honda Civic (Hybrid) vs. a Honda

Civic (Gasoline) using the following

figures:

Honda Civic (Hybrid)

Initial Cost: $19,650

Tax Incentive: $1500

Miles per Gallon: 48 mpg

Honda Civic (Gasoline)

Initial Cost: $17,260

Tax Incentive: $0

Miles per Gallon: 40 mpg

Hybrid Gasoline

Initial Cost

$19,650 $17,260

Tax Incentive

$1,500 $0

Fuel Economy

48 mpg 40 mpg

Difference in

Initial cost

(+) $2390

Difference in cost

after tax incentive

(+) $890

Fuel economy at a

gas rate of $2.10

per gallon for

one year at 10,000

$525/yea

miles

$438/year r

mount of time till

hybrid savings

exceed gasoline

10.2

initial savings

years

• Investigate the rate at which hybrid

vehicles have been decreasing in

initial cost. What might be some

factors for this decrease? Do they

expect hybrid vehicles to someday

have a lower initial cost then

gasoline engine vehicles?

• Research other types of alternative

fuels. Is a hybrid more cost

efficient then compressed natural

gas (CNG), hydrogen fuel cells,

propane, or biodiesel?

3 Determine a plan for large

number fleets of automobiles

to transition for traditional

gasoline engines to

alternative fuel engines.

The mayor of a large city in your

area has asked your class to develop a

plan to reduce emissions created by his

fleet, including school buses, public

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buses, sanitation trucks, police,

emergency vehicles, and the city fleet of

automobiles. Divide the project into six

parts and in each part develop a plan to

present to the mayor, listing

recommendations and costs for each

type of vehicle and the rationale for

each recommendation.

List the recommendations of each

part by vehicle category. Where there

are several recommendations, debate

and defend recommendations until a

consensus is reached.

Learning Objective: You will

understand different forms of alternative

fuels as well as a greater understanding

of citywide economics.

Controls and Variables: None

Materials and Equipment: Pen, paper

and access to the Internet for research.

Safety and Environmental

Requirements: None

Suggestions: Invite area experts to

visit the classroom to discuss alternative

fuel vehicles.

Present your findings in a formal report

to be sent to your local mayor.

Quantify the relative amount

of CO

given off by the

methanol vs. ethanol during

the combustion process.

Utilize a fish aquarium pump to

pull samples of exhaust fumes from

above the calorimeter experiments

(done in project idea one) and let it

pump the collected gases into a test

tube of bromothymol blue solution or

red cabbage juice to determine the

relative CO

content. (Bromothymol

blue will change from blue to green to

yellow in the presence of CO

Learning Objective: You will be able

to test for the presence of CO

in the

combustion of ethanol and methanol

and qualitatively compare the two

amounts.

Controls and Variables: The different

amounts of ethanol and methanol that

are used can either be held constant or

varied depending on the experiment.

Hold the solution of bromothymol blue

or red cabbage juice constant through

each test.

Materials and Equipment: A fish

aquarium air pump with tubing, air

pump in sealed container with inlet and

outlet air tubes, two test tubes, scale to

determine mass of fuel consumed,

material from project #1, bromothymol

blue solution or red cabbage juice, and

stopwatch.

Safety and Environmental

Requirements: Safety wear (goggles,

lab apron, heat resistant gloves), well

ventilated area for burning, and waste

container. (Do not pour ethanol or

methanol down the drain or into

garbage.)

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Places to Purchase:

Bromothymol Blue, 0.04% in Ethanol

http://www.baddley.com/ ($12.00 – 125

ml)

http://www.clarksonlab.com/salesaz.ht

m ($14.95 - 5 g powder reagent)

What goes into building a

hydrogen fuel cell car?

There are many different

available models of hydrogen fuel cell

cars that can be bought. Try just using

the basic parts to build a unique

hydrogen fuel cell vehicle.

Learning Objective: You will be able

to understand the hydrogen fuel cell

process of how water (through

electrolysis) is turned into power to run

a motor.

Controls and Variables: A simple

hydrogen fuel cell vehicle kit will give all

the components necessary; everything

else is up to you.

Materials and Equipment: Hydrogen

fuel cell vehicle kit, some power tools

may be necessary when building custom

vehicle bodies. You will also need

smooth surface to run the vehicles on.

Safety and Environmental

Requirements: Safety protection

should be taken when building the cars

from scratch. You also require

protection from small electrical circuits

and a moving motor.

Suggestions:

1. See who can build the fastest

vehicle by changing wheels and axis,

body types, and gear sizes.

2. Determine the efficiency of the

hydrogen fuel cell.

Places to Purchase:

Hydrogen Fuel Cell Kits

http://electronickits.com/kit/complete/so

lar/fuelcell.htm

(~ $125)

http://sciencekit.com/category.asp_Q_c

_E_427448

(~ $220)

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References:

http://www.nap.edu/readingroom/books

/nses/html/

http://www.nrel.gov

http://www.fueleconomy.gov/

http://www.need.org/needpdf/Alternativ

eFuels.pdf

Photo References:

http://www.need.org/needpdf/Alternativ

eFuels.pdf

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