Question

Professor has 14 photovoltaic panels on his roof, and the effective PV area OF EACH PANEL is 3ft x 5ft. At 12:20PM on October 12th, these panels were generating 2 kw of power.

At that same time, the solar radiation measured by the weather station showed that the incoming solar radiation was 415 watts/m2 .

1. Determine the instantaneous efficiency of the system at this point. Note that you need to convert from square feet to square meters, and from kw to watts.

2. Professor has of course made calculations, and determined that the 14 panels produce about 62% of their household needs over the course of a year. In the summer and during the day, the panels produce more power than is consumed, and the electricity is fed back to the net – this is called net metering. Given the numbers above for the number of panels, how many more panels does his family need to put in to increase the capacity for their home?

3. An average household (3.3 people) consumes about 1000 kwhr of electrical energy / month, which is supplied by 30 solar panels. Given the data from above, approximately how large an area of PV panels would a utility need to be put up to cover the electrical needs of 100,000 citizens, calculated in square feet, and square meters.

4. In problem 2 above, assume that new panels now have an effective efficiency of 30%, and will cost 10% more than the type of panel they have. What is more cost effective – to buy the higher efficiency panels, or the old ones? Note: this question does require a calculation. You must have evidence for your answer.

Answer 1