Note: This column appears in the Wednesday, Feb. 28 newspaper on Page A3.
The year was 1839, and humanity learned it could harness the power of the sun. Alexandre Edmond Becquerel found that certain elements can produce electricity after exposure to sunlight, dubbing this phenomenon the photovoltaic effect.
A few years later in 1876, this theory was put into practice when William Grylls Adams and his student, Richard Evans Day, found that selenium and platinum reacted together when exposed to sunlight. This showed that energy could be produced from the sun’s rays without the aid of a mechanically-driven machine.
These discoveries sparked advancements in solar technology, eventually resulting in the solar panel.
But how does a solar panel produce watts upon watts of energy without even moving?
The glossy solar panels you see in deserts, rooftops and hills actually consist of much smaller, interconnected units called photovoltaic cells (or PV cells).
These PV cells also consist of smaller parts: two layers of conductive material (normally silicon).
Our first layer, the “n-type,” is dipped in phosphorus and is surrounded by electrons. The bottom layer of the cell is called the “p-type” layer. It is dipped in boron and thus carries fewer electrons than the top layer (giving it a positive charge).
Here’s a mini-science lesson: opposites attract. Electrons carry a negative charge, and they want to travel to places that have positive charges. They float and can essentially be “knocked loose” by other particles.
The space between the p-type and n-type layers is called the P-N junction. Adventurous electrons will flow from the two layers, creating an electric field.
Photons are particles of sunlight; they have the power to disrupt the electric field. Photons force out electrons and take up space in the P-N junction. Displaced electrons fly away from the two layers and travel down a wire connected to the PV cell.
Boom! You are now the proud owner of an electric current.
All of the cells generate power as the sun’s ray hit them; during certain times of the day, sunshine will be more intense and direct; thus, more power can be produced.
Just 18 days of sunshine globally could produce the same amount of energy as all of the planet’s reserves of coal, oil and natural gas, according to the Union of Concerned Scientists.