# Chapter 16 - Think and Solve: 38

Each square meter of collector receives 200 watts of solar power on average, but because of the 10% efficiency, it only supplies 20 W of electrical power. So to meet the average 3 kW requirement, you'll require $\frac{3000 W}{20 W/m^{2}} = 150 m^{2}$ of collector area. This is the area of a square that is 12.2 m on a side. It might fit in a yard, but is larger than most roofs can accommodate.

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