Let’s say that I put a big Fresnel Lens the ideal number of meters away from my solar panels in the ideal position and at the ideal angle (no, I don’t have solar panels IRL). The focused sunlight then lands on my panels.
Does this:
a. Produce mad extra power … profit!
b. Put the panels at risk of melting/burning/overloading/words like that?
c. Do absolutely nothing.
B. You won’t get moar powah. You WILL overheat and burnout the spot on the panel where you are focusing the funslight, causing it to fail.
That would be a very bad idea. You don’t want to focus all of the sunlight at a single point. That will completely fry that part of the solar panels. What you want to do is have the light spread out evenly over the entire surface of the solar panels.
You could probably accomplish that if you put the Fresnel lens significantly less than the ideal distance away from the solar panels. That will focus a larger amount of light down to a smaller surface area, increasing your solar output. At some point though you’ll damage the cells in the solar panel, so this has its limits. Depending on your area you might be able to increase your solar panel output by somewhere between 10 and 30 percent or so. You’d have to look at some actual specs to figure out exactly how far you could push it.
Incidentally, there is a type of solar power that does focus the sun to get more power. It’s called a molten salt power plant. As the name implies, it uses focused sunlight (typically focused using mirrors, not lenses) to melt salt. Water pipes run through the salt, and the heat turns the water into steam. From there on out, the plant is just like any other steam powered plant (coal, nuclear, natural gas, etc). The steam is used to spin a turbine which is connected to a generator that makes the power.
The big advantage this has over solar panels is that once you get the salt hot enough, it takes it a long time to cool. So this type of plant can ride through momentary cloud cover and can even run overnight while still producing power. As long as you have enough molten salt to get through the night without it losing all of its heat, you’re good.
There was a major plant in the southwest that was built using this principle. Unfortunately, it lost money for all of its investors, so as innovative as the technology is, you’re not likely to see many more plants like it in the near future.
You could theoretically do the same thing with a Fresnel lens, but that would cost significantly more than just using mirrors to focus the sunlight.
More info here:
Here’s a video example of a test of Fresnel lens focusing sunlight on a small panel.
TL;DR: with the panel placed so that the light is distributed over the full surface of the panel (i.e., not at point focus), the panel generated nearly one volt higher and with greater current capacity than before light concentration, but heated up and began to lose efficiency, to the point of finally not being much better than un-concentrated light.
A followup experiment with a passive heatsink on the solar panel worked much better, sustaining the higher voltage and current for tens of minutes.
But the energy increase doesn’t seem to have been earthshaking (maybe tripling the wattage output). And practically speaking, there is a lot of engineering needed to do this on a large scale, and much care and feeding to maintain the lens assembly in addition to the PV panel, and you reduce the density of actual PV panels deployed by spacing them at intervals that match the lens size and focus.
If large Fresnel lenses cost about the same as solar panels you could be spending more money to achieve the same output.
Heat is the enemy of solar power. Output drops off quickly as the solar cells heat up. I worked at a facility that tested arrays of cells. All of that data you see about how much power your solar panel will output is generated in a split second using a large Xenon lamp and a computer that ramps the resistance from zero to infinity to generate the knee curve of voltage vs current.