If a pc left on over night for a year it uses ?of energy. this produces the same carbon as a car journey from?

Question

If a pc left on over night for a year it uses ?of energy. this produces the same carbon as a car journey from?

Answer 1

A computer power uses maybe 100 to 300 W when on and running.  If you have your computer set to go to sleep when you don't use it, then it uses less than 10 Watts.  The amount of energy is kW (W/1000) times hours -- so if it is running, 1kWh to 3 kWh, and if in standby, less than 0.1 kWh.  This is the energy per night -- so for 365 nights, you're looking at between 36 kWh (standby) to 1000 kWh (normal) for a year.

You'll have to check with your local electric company to see how much CO2 os emitted per KWh.  It depends on the mix of energy sources.  See http://www.eia.doe.gov/cneaf/electricity...  

In the US the average is about 1.3 pounds of CO2 per kWh.  So in a year 1300 pounds of CO2 (if your computer doesn't go to standby)

Cars produce around 20 pounds of CO2 per gallon of gas.  So 1300 pounds of CO2 is like 65 gallons of gas.  The rest depends on your gas mileage ... if you drive a HUMMER with 2 mpg, this is like a 130 mile trip.  If you drive a Prius with 50 mpg, this is more than 3000 miles (a trip from coast to coast).