Sizing a Solar PV System:

The Rusk’s own fairly large house near San Francisco and the following spreadsheet shows their month-to-month energy use for two years.

problem 1: What is their monthly average energy use? Why do you think their use peaks twice a year?

problem 2: find out the size of the solar PV system (kWh DC,STC) they will need in order to have a zero dollar electricity bill annually (use an average over the two years). Assume that you are using 14.9% efficient panels with an 80% de-rating factor. Also assume that your inverter is 95% efficient. Use an average solar insolation of 5.5kWh/m2/day for their location.

problem 3: Assume this system will be mounted on the roof. How big will the area of solar collector be? Is this a reasonable size for a house (i.e. are roofs actually this big)?

problem 4: What is the AC,PTC per square meter for the system? Assume that the 80% de-rating factor gets you from DC,STC to DC,PTC.