Rough Values of Power of Various Processes (watts)
|Solar power in all directions||1027|
|Solar power incident on earth||1017|
|Solar power avg. on U.S.||1015|
|Solar power consumed in photosynthesis||1014|
|U.S. power consumption rate||1013|
|U.S. electrical power||1012|
|Large electrical generating plant||109|
|Automobile at 40 mph||105|
|Solar power on roof of U.S. home||104|
|U.S. citizen consumption rate||104|
|Solar power per m2 on U.S. surface||102|
|One light bulb||102|
|Food consumption rate per capita U.S.||102|
Energy Content of Fuels (in Joules)
|Energy Unit||Joules Equivalent (S.I.)|
|gallon of gasoline||1.3×108|
|standard cubic foot of natural gas (SCF)||1.1×106|
|barrel of crude oil (contains 42 gallons)||6.1×109|
|pound of coal||1.6 x 107|
|pound of gasoline||2.2 x 107|
|pound of oil||2.4 x 107|
|pound of Uranium-235||3.7 x 1013|
|ton of coal||3.2 x 1010|
|ton of Uranium-235||7.4 x 1016|
|1 Btu||1055 joules||or||778 ftlb||or||252 cal|
|1 calorie||4.184 joules|
|1 food Calorie||1000 calories||or||1 kilocalorie|
|1 hphr||2.68 106 joules||or||0.746 kwh|
|1 kwh||3.61106 joules||or||3413 Btu|
|1 eV||1.610-19 joules|
Fuel Requirements for a 1000MWe Power Plant
(2.4 1011 Btu/day energy input)
Coal: 9000 tons/day of 1 “unit train load” (100 90 – ton cars/day) Oil: 40,000 bbl/day or 1 tanker per week (note: “bbl” means barrels)
Natural Gas: 2.4 l08 SCF/day
Uranium (as 235U): 3 kg/day
Note: 1000 MWe utility, at 60% load factor, generates 5.3109 kwh/year,
enough for a city of about 1 million people in the U.S.A.
(Note: MWE is an abbreviation for megawatts-electrical output)
Geographic Energy Needs
U.S. Total Energy Consumption (1990)
= 82.11015 Btu (82.1 Quads) = 38.8 MBPD oil equivalent = 86.6109 GJ
Everyday Usage and Energy Equivalencies
1 barrel of oil = driving 1400 km (840 miles) in average car
1 kwh electricity
= 1½ hours of operation of standard air conditioner
= 92 days for electric clock
= 24 hours for color TV
One million Btu equals approximately
90 pounds of coal
125 pounds of ovendried wood
8 gallons of motor gasoline
10 therms of natural gas
1.1 day energy consumption per capita in the U.S.
Power is the amount of energy used per unit time – or
how fast energy is being used.
If we multiply a unit of power by a unit of time, the result is
a unit of energy. Example: kilowatt-hour.
|1 watt||1 joule/s||or||3.41 Btu/hr|
|1 hp||or||2545 Btu/hr||or||746 watts|
Power Converted to Watts
|1 Btu per hour||0.293 W|
|1 joule per second||1 W|
|1 kilowatt-hour per day||41.7 W|
|1 food Calorie per minute||69.77 W|
|1 horsepower||745.7 W|
|1 kilowatt||1000 W|
|1 Btu per second||1054 W|
|1 gallon of gasoline per hour||39 kW|
|1 million barrels of oil per day||73 GW|
Rough Values of the Energies of Various Occurrences
Cost of Various Fuels
|Electricity||1 Kwh||$0.10||appliances, motors|
|Natural Gas||1 Therm||0.60||heating|
|AA battery||1 battery||0.80||portable electronics|
|Milky Way candy bar||1 bar||0.60||food|
Worldwide Power Use-History
“Developed” countries average (1990):
· 1.2 billion people 7.5 kilowatts/per person = 9.0 terawatts
The rest of the world (1990):
· 4.1 billion people 1.1 kilowatts/person = 4.5 terawatts
|World Population (est.)
|Year||Average Power Use
How much energy is there in a barrel of
Q: With oil prices around $100 a barrel and gasoline at $4 a gallon, is it really worth that much? How much energy is in a barrel of oil anyhow?
A: First, oil barrels are not the same size as the 55-gallon drums that are in common use today. An oil barrel is only about 75 percent as large at 42 gallons. Although the barrel is used as the unit of measure, actual barrels are no longer used to ship crude oil. The history of the barrel dates to the early days of oil production in Pennsylvania oil fields in the 1860s. There was no standard container, so oil producers used whatever containers were commonly available. According to the Oil Region Alliance of Business Industry & Tourism in Venango County, the 40-gallon whiskey barrel was readily available and most commonly used. The 42-gallon barrel became standard by 1872, the two extra gallons were apparently added to ensure that customers would get at least 40 gallons. It seems there was distrust of the oil industry from the beginning.
The 5.8 million Btu figure was established by the IRS for energy tax purposes and is called a Barrel of Oil Equivalent, or BOE. One barrel of oil has the same energy content as 5,800 cubic feet of natural gas. A cubic foot of natural gas contains about 1,000 Btu. For electricity, 1 barrel is 1,700 kilowatt hours.
1 barrel = 1,700 kilowatt hours.
So, is oil really worth $100 a barrel? Another way of looking at it is to compare oil to a horse. A horse laboring a standard 40-hour work week (eight hours a day, five days a week, 50 weeks a year) would have to labor for more than one year to produce the energy in a barrel of oil. Do you think a horse could be fed and maintained for a year for $100? Not likely.
Human labor is even worse. A fit human adult can sustain about one-tenth of a horsepower, so a human would have to labor more than 10 years to equal a barrel of oil.
Oil and oil products have the advantages of being easily combustible with high energy content. Additionally, oil is widely available and is easily transported through ocean tankers, tank trucks and pipelines. Gasoline and diesel fuel are easily and safely dispensed into our vehicles, and heating oil is similarly delivered to our homes.