PV Gap

Zachary Said:

solar energy demand extra credit problem?

We Answered:

The amount of solar energy falling onto the solar panels over an entire year can be found through multiplication:

1 KW/m^2 * 100m^2 * 1,000h = 100,000 KWh

To calculate the energy required by the house, we must combine the electrical demand with the heating demand:

Electrical:
15,000 KWh
Heating:
1,000g * 15,000 Btu/g * 0.000293 KWh = 4,395 KWh
Total:
15,000 KWh + 4,395 KWh = 19,395 KWh

The house uses 19,395 KWh. Therefore, the sun is providing enough energy to the roof to power the house (and a lot of extra). However, what is missing is the efficiency of the solar panels. The solar panels cannot capture 100% of the solar energy. Basically, to be able to power the house they must be able to capture:

19,395 / 100,000 * 100% = 19.395%

Approximately 19.4% of the energy that reaches the roof. Unfortunately, average solar panels have an efficiency of about 12% meaning that no, they could not power the house. Fortunately, if price wasn't a problem, expensive panels can be bought that convert up to 20% (enough to power the house, but only just!).

So the answer is 'no' under normal circumstances, but 'yes' it is possible with expensive technology