And of course, sunlight has a wide range of wavelengths and it's almost impossible to convert >1000 nM light to electricity, so you can't get close to 100%.
The problem with current cells isn't efficiency but cost. 5% efficient cells that were cheap (including mounting & protection) would be a breakthrough.
> The problem with current cells isn't efficiency but cost. 5% efficient cells that were cheap (including mounting & protection) would be a breakthrough.
It depends. My house has a finite amount of roof space.
If a solar farm has to be too big, it can only be very remote and then there's a distribution problem. (Consider road sign lights. You'd rather not run wires to them, so "on sign" solar is a natural, but size matters.)
You're right about remote applications, of course. I'm thinking about replacing coal with solar on a large scale.
Roofs are a silly place to put solar cells. Like everyone growing wheat on their roofs. Farms are the right model for harnessing lots of sunlight to grow food or make electricity.
The problem with current cells isn't efficiency but cost. 5% efficient cells that were cheap (including mounting & protection) would be a breakthrough.