The angle at which the light hits the panel θis measured from a line perpendicular to the surface, meaning that a solar panel produces the most power when the light is hitting it from the front (θ = 0), and cosine(0) = 1, so
So let’s do some quick math. The intensity of sunlight at Earth’s location is about 1,361 watts per square meter. So, let’s say your solar panel is 1 meter by 1 meter and is 25 percent efficient (very optimistic). If the light hits it at a 30 degree angle, this solar panel will provide 294.7 watts of power.
Now, our solar-powered 737 has Many We need more power than that. We can calculate the surface area needed to generate 10 million watts. For simplicity’s sake, let’s assume that the light is perpendicular to the panel (not realistic of course). In this case, we would need 29,000 square meters of panels.
For comparison, a 737 has a wingspan of 125 square meters. If you covered that with solar panels, you could generate 42 kilowatts of power. That’s great, but not nearly enough for a passenger plane — specifically, it’s 0.4 percent of the power needed to stay in the air.
After all, it’s pretty hard to imagine how to build a solar-powered passenger plane. But that doesn’t mean electric planes are completely impossible. Maybe one day we’ll see some amazing battery-powered planes.
Ah, but what about a real solar-powered airplane? The key is to fly slower and with less mass to reduce drag, and if the wings are big enough, you can get enough power to fly until it gets cloudy.
