This assigment is due by 8 pm, Friday January 23

This assignment is meant to get you to practice with numbers and various scaling relations.

1. In 2007, the US produced electrical power at the scale of 0.9 terrawatts. Calculate the per capita electrical power in the US (this is equivalent to the amount of power required per individual at any given time).

2. Energy = power x time; Power is measured in units of watts (kilowatts, megawatts, gigawatts, terrawatts) and is instananeous. Power used over time is energy. Based on your calculation in question 1, and assuming an average energy cost of 9 cents per KWH, what is the monthly baseline per capita electricity cost to a US citizen.

3. One gallon of gasoline has an energy density storage equivalent of about 34 KWH. In Eugene the price of electricity is 7.5 cents per kwh. You have two options on what kind of car to buy - a new gasoline powered car or a plug-in electric vehicle. Your plug-in EV uses 1 KWH for every 2 miles driven. Your gasoline powered car gets 40 miles per gallon. Finally, your PHEV has a charging efficiency of 70% (meaning for each delivered KWH only 0.7 KWH is stored in the battery)
   a) What is the electricity cost of the equivalent of a gallon of gas?

   b) If gas is $2 per gallon, what is the total cost of going 100 miles for your PHEV compared to the gasoline powered car.?

4. Your PHEV requires a 220 Volt source. If you place that voltage source on a standard household circuit with a maximum current of 15 amps, how long does it take to charge the PHEV to the equivalent energy contained in 1 gallon of gas?

5. Large power plants come in unit capacity of 1000 MW of output electricity (MWe).
   a) Estimate how many large new power plants could be avoided if every house in America replaced 2 100 Watt incandescent bulbs with 2 20 Watt compact fluourescent lightbulbs (CFL).

   b) A 20 Watt CFL contains 4 milligrams (mg) of Mercury. The number one source of mercury pollution in the US is Coal fired electricty. In 2007 Coal Fired Electricity was at a power level of 450,000 Megawatts (MWe). Mercury emissions from coal occur at a level of 200,000 mg per MWe. Based on switching out these 2 lightbulbs, show that your "Mercury Footprint" has actually been reduced by switcing to CFLS.