Pushing, pulling and falling has the Wolf Man confused about energy. He thinks that one type of energy is just as good as another. And why shouldn't he? Most people do and take that notion right into the Ghostly Graveyard! And this problem with Carbon Dioxide (CO2) and greenhouse gasses and global warming. That's got the furry graveyard sexton worried too. You realize that the only way different types of fuels can be compared is to examine their energy content on a standard scale.

Energy Resource Energy Content (BTU) Amount per MBTU CO2 Produced (per unit of fuel) Pounds of CO2 produced per million BTU wood 8,000/lb 125 lbs. 2.59 lb. CO2/lb 323.8 coal 12,250/lb   2.48 lb. CO2/lb   fuel oil 140,000/gal 26.4 lb. CO2/gal   gasoline 125,000/gal   23.8 lb. CO2/gal   LP gas 95,500/gal   12.1 lb. CO2/therm   electricity from coal 3,413 kwH   2.37 lb. CO2/kwH   electricity from oil 3,413/kwH   2.14 lb. CO2/kwH   electricity from natural gas 3,413/kwH   1.32 lb. CO2/kwH

After a quick trip on the Web you've summarized the main types of fuels used in the United States, identified their energy content in BTU (British Thermal Unit) and the amount of carbon dioxide produced per unit of fuel. Now you've got to do some calculations to help the Wolf Man make meaningful comparisons. A calculator will help! EXAMPLE: Wood has 8,000 BTU's (British Thermal Unit) per pound. How many pounds of wood will it take to produce 1 million BTU (British Thermal Unit) Ans. 1,000,000/ 8000 = 125 pounds. Each pound of wood produces about 2.59 pounds of carbon dioxide. So burning 125 pounds of wood produces 323.8 pounds of carbon dioxide (2.59 X 125 = 323.8 pounds).

Rank-order the fuels according the amount of CO2 they produce per MBTU's. Explain the list to Wolf Man and make some recommendations on the kinds of fuels he should buy. What are some other things he should consider?

Some fuels are better suited to certain tasks than others. For example it only takes 8 gallons of gasoline to produce a MBTU's but it takes 125 pounds of wood to produce the same amount of energy. Can you imagine driving a car around town with 125 pounds of wood loaded in the trunk? Use this notion of energy density to explain the following: "Natural gas is the fuel of choice for heating water, heating homes and cooking." · "Coal is an abundant fossil fuel but it's dirty." "Gasoline can never be replaced by biomass fuels like wood." "Burning natural gas to make electricity is a terrible waste (or a good use) of a precious resource." EXAMPLE: Wood has 8,000 BTU's (British Thermal Unit) per pound. How many pounds of wood will it take to produce 1 million BTu's (British Thermal Unit)? Ans. 1,000,000/ 8000 = 125 pounds. Each pound of wood produces about 2.59 pounds of carbon dioxide. So burning 125 pounds of wood produces 323.8 pounds of carbon dioxide (2.59 X 125 = 323.8 pounds).