““The World We Create”The World We Create”NATS 101NATS 101Section 6Section 6

Remember, Project 1 due this Tuesday

02/11

Be aware! Cooperate!You will be asked to

actively participate in the Debate today.

UNIT 1: Energy Sources,

Conventional or Alternative?

Alternative Sources

Our FocusEvaluate an alternative energy source considering

a variety of factors such as:

Availability of source; Renewability; Environmental impact; Energy content; Price; Diversity of transformation devices; Efficiency of transformation devices; Political, economic, and social impact;

Solar Energy Two different types of solar energy:

Energy is captured by solar devices, such as photovoltaic cells.

Other energy sources that are created by energy from the sun, such as biofuels.

Primary

Direct

Secondary

Indirect

$$ Solar Panels $$

You’re building a new house, and are particularly concerned with “Going Green”, you’re thinking of

installing Solar Panels.How many do you need?How much does it cost?

Is it worth doing?

Energy Needs1. Energy used per day: (24 h) x (1.2 kWh / h) = 28.8 kWh 28.8 kWh x (1000 Wh / kWh) = 28,800 Wh

2. Energy generated per day In Tucson: (5.4 h ) x (10 Wh / h / ft2) = 54 Wh / ft2 (total during Tucson’s daylight hours)

3. Square feet of solar panels needed:

(28,800 Wh) x (1 ft2 / 54 Wh) = 533 ft2 in Tucson

Let’s Calculate: CostAgain discuss with your group the following

calculations (you have ~5 minutes) :

4. What is the total cost for powering a) Tucson Home; b) Chicago Home using solar panels?

5. Over 20 years the total energy required to operate the average home is 210,240 kWh. Given this energy requirement and the cost you calculated above, what is the cost (in cents / kWh) of the solar panels over this 20 year period?Compare this with the cost of coal based energy 8.35 cents /kWh.

You have 5 minutes

Cost Determination4. Cost for a single home in Tucson: (533 ft2) x ($56 / ft2) = $29,866

5. Cost over 20 years in Tucson: ($29866) x (100 cents / $1) = 2986666 cents

(total cost in cents) / (total energy requirements) =(2986666 cents) / (210240 kWh) = 14.205 cents/kWh

Analysis:6. Given all the data you have, would you

install solar panels to operate your home? Why or why not?

7. What considerations did you have to think about in making your decision whether or not to install solar panels.

8. Which of your considerations did you value the most? Why?

You have 5 minutes

Solar Energy

Weaknesses:

Cost, device efficiency, intermittency, storage.

Strengths:

Renewable, availability, peak service, long-lasting, no emissions, low maintenance.

However, when and where electricity is delivered is often

more important than price.

BiofuelsChemical compounds derived from renewable resources such as plant or animal materials

that can undergo a combustion reaction.

Ethanol

Produced by fermentation of sugar-rich substrates (corn,

starch, sugar cane, etc.)

Biodiesel

Made from vegetable oils, animal fats or recycled

greases.

The Great DebateShould we us Ethanol as an

alternative Fuel?

ObjectivesUpon completion of all debates,

you should be able to:

Form an opinion either for or against the use of ethanol as an alternative fuel.

Be able to justify that opinion using pros or cons from “at least” 3 of the 4 debates

4 Categories4 Categories

FRONT CLASSROOM

A FC

D

E

B IG

H

Ethanol Debate

Economy Con

Economy Pro

Dependence Pro

Dependence Con

Pro Con Environment

Energy Supply Pro

Energy Supply Con

The Rules• Moderator presents question• 1 minute per initial response• 30 seconds per rebuttal• Repeat for other side• Questions from other group

members (time permitting)• Same rules apply from above

Our ExpectationsTo Earn Participation Points Today:

• Be Courteous• Respectful Listening

• Take Notes (Hint, Hint)

Before We Begin

Debate #1$$ Economy $$

Q#1: (Pros) If the U.S. stopped producing ethanol, how would it hurt our economy?

Q#2: (Cons) If the U.S. increased the production of ethanol, using current methods, how would it hurt our economy?

Debate #2Environment

• Q#1: (Cons) Using ethanol (as an alternative) has been reported to reduce pollution. Do you agree with this claim? Please elaborate

• Q#2: (Pros) Would you say that ethanol use is good for the environment as a whole?

Debate #3Energy Efficiency

• Q#1: Ethanol contains approximately 34% less energy per unit of volume than gasoline, and therefore burning pure ethanol in a vehicle would result in a 34% reduction in miles per gallon, why would we possibly want to use ethanol as an alternative fuel for gasoline?

• Q#2: The U.S. produces most of its ethanol from corn what makes this way less efficient and effective than places like Brazil who produce their ethanol from sugar cane?

Debate #4• Q#1: (Pros) In regards to our country’s

“dependence,” why should our country invest in ethanol production?

• Q#2: (Cons) Will production of ethanol be a means to an end of our “dependence?” Justify

Dependence on Foreign Oil

Let’s Recap:• We watched 4 different debates on

whether or not we should use ethanol as an alternative source of fuel.

• We heard differing opinions on those debates.

• Those debating shared with us their reasons and justifications for their opinions.

Now, Take a Minute or Two…

• Did your opinion (either for or against the use of ethanol as an alternative fuel source) change after watching or taking part in the debate? Please write it down individually on a piece of paper.

• What’s something that you learned today from the debate?