Energy Units & ConsumptionESM 102

Sources of Energy

Natural Gas0Sold in units of THERMS

0 100 cubic feet0Hydrocarbon mixture (mostly methane)0Uses: generating electricity, heating houses, providing

heat & power to industry and vehicles0Found deep in underground rock formations & above

crude oil reservoirs0Cheaper than oil, easy to transport, burns hotter &

cleaner than other fossil fuels0Leaks of natural gas into atmosphere

Electricity

0Sold in units of kilowatt hours (kWh) 0 1000 watt hours

0Sources of electricity:0 Fossil fuel combustion0 Wind power0 Hydropower

0Can’t be easily stored…must generate as much as needed

Kilowatt Hours

Heating Oil

0Sold in units of gallons0Low viscosity, flammable liquid petroleum similar to

diesel fuel0Stored in above or underground storage tanks 0Fuel for furnaces or boilers

Gasoline0Sold in units of gallons0Petroleum derived liquid used for fuel in internal

combustion engines0 In US and many other countries, gasoline blended

with up to 10% ethanol0US accounts for 44% of world wide usage

Wood

0Sold in units of cords0 = 4’ x 4’ x 8’ stack of wood0 = 250 copies of Sunday NYT0 1 forested acre produces 10-15 cords

0Amount of energy depends on type of wood0 Density0 Water content

Energy in terms of BTUs

01 Calorie = 3.968 BTUs0Heating Oil: 1 gallon = 138,690 BTUs0Gasoline: 1 gallon = 124,238 BTUs0Natural Gas: 1 therm = 100,000 BTUs0Electricity: 1kWh = 3412 BTUs0Coal: 1 short ton = 19,858,000 BTUs

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