One of the most abundant energy sources on the Earth is light, or solar radiation, from the sun. But how do we plug into this vast energy resource?
Our first hints come from plants, bacteria, and protists. These organisms have been using photosynthesis to generate biomass for a long time, but what does this mean?
Cells that perform photosynthesis utilize the solar radiation of light from the sun to produce glucose, or food energy. In chlorophyll a, or other accessory pigments, solar radiation is absorbed, allowing the conversion of carbon dioxide and water into glucose, which releases oxygen.
CO2 + H2O → C6H12O6 + O2
The energy chlorophyll a absorbs causes electrons to be excited. When chlorophyll a’s electrons are excited enough, they leave. These free electrons are then transferred to electron carriers that aid in reactions generating energy and biomass for the organism.
The idea that solar radiation can be converted into electricity is one of the founding elements of solar power. Electricity is energy from the flow of electrons. So, how do we free electrons in artificial cells and generate a flow to produce electricity?
Photovoltaic (PV) “Solar” cells were developed to do just this. In one solar cell, semi-conductive materials (usually silicon) are treated at the front and back of the cell to generate positive and negative ends. When sunlight shines on silicon, electrons are released. The electric field produced by the differently charged ends causes the electrons to flow, and this flow is direct current (DC) electricity!
Check out the video below to learn more about how solar panels work!