Now that we've talked about leaves and why they change color, let's look more closely at their all-important function, that of making food for the tree. How do they do it?
A plant’s objective is to make excess stored energy to nourish the tree through winter. Therefore, it makes energy in the stored version of glucose. The sunlight powers a chemical reaction within the chloroplasts to bottle up energy within the bonds of the very stable sugar molecule. The energy can then be used when the bond is broken.
A solar panel’s purpose is to convert sunlight energy into electricity. The panel is like a deck of cards (see picture), with each card made of a substance that promotes electrons to move in one direction, creating an electrical current. The middle yellow layer contains substances that either donate or accept freed electrons. So first, the electrons have to be freed, and then they are forced to flow in one direction.
When sunlight hits the panel, energy is imparted to certain electrons, exciting them to a higher energy level (level 2) that is enough to break away from its parent atom’s attractive hold upon it. Now that the electron is free, it is attracted toward positively-charged materials, since it itself is negatively charged. Sandwiching the yellow layer is one layer that is negative (anode) and one that is positive (cathode). So all the electrons move away from the anode and toward the cathode. The electric current is produced.
The last step is to convert this Alternating Current to a Direct Current to make usable electricity.
Solar panels are generally around 14% efficient, so, a lot of continuous sun is needed to produce a fraction of the energy used by a household. A battery is also needed to store the excess electricity. Still, the addition of electricity produced with NO waste product is a huge advance.