How do Solar Panels Generate Electricity?

Sunlight is the most abundant source of power available to us. Every hour and a half, the sun showers the earth with enough rays to power the entire world for a year. How solar panels generate that much electricity might still seem like a bit of a mystery.

To understand the mechanism of electricity generation from the solar panels, we need to cast light upon the principles of photovoltaic technology, the components of solar panels, and the underlying science that makes it all possible.

The Mechanism of Solar Energy Generation from Solar PV Panels

Sunlight consists of photons. When the sunlight falls on the surface of solar cells, these photons are absorbed by the semiconductor material. This absorption process transfers energy from the photons to the electrons in the semiconductor.

Electron excitation: The energy from the photons excites the electrons and gives them enough energy to break free from their atomic bonds. This creates electron-hole pairs within the semiconductor material.

Electric Field Creation: Photovoltaic cells are made of two layers of semiconductor, which generate an electric field when combined. This electric field drives the free electrons and  creates electric current.

The conversion happens in 4 stages:

1. Sunlight Hits the Solar Panel

Solar panels are made up of many smaller units called solar cells, which are typically made from materials like silicon. When sunlight (made of photons) hits the solar panel, it strikes the solar cells.

2. Solar Cells Convert Light to Electricity

The solar cells in the panel absorb the photons from the sunlight. Inside each solar cell, there are two layers of silicon with different electrical charges, creating an electric field. When photon particles hit the silicon surface, the electrons cut loose from their atoms. These free electrons are then pushed by the electric field towards the surface of the solar cell.

3. Creation of Electric Current

The movement of electrons creates an electric current. This flow of electrons is what generates electricity, but it’s in the form of direct current (DC), which means the electricity flows in one direction.

4. Conversion to Usable Electricity

Regular home appliances like fans, lights, refrigerator, washing machines, AC, and grinders use alternating current (AC) electricity. And AC current flows in both directions. To make the electricity generated by the solar panels usable in your home, electricity needs to be converted from DC to AC. This conversion is done by solar inverter. The inverter takes the DC electricity from the solar panels and changes it into AC electricity.

Components of a Solar Panel

To better understand how these processes come together, it helps to look at the key components of a solar panel:

Solar Cells

The individual units that perform the photovoltaic conversion. Each cell generates a small amount of electricity, but when connected in series and parallel within a panel, they produce a substantial amount of power.

Glass Layer

The top layer of the panel is made of tempered glass, which protects the delicate solar cells from physical damage and environmental elements while allowing sunlight to pass through.

Anti-Reflective Coating

To maximize the amount of light absorbed by the solar cells, an anti-reflective coating is applied to reduce the reflection of sunlight off the surface of the cells.

Encapsulant

This is a layer of protective material (often ethylene-vinyl acetate) that encases the solar cells and provides insulation and protection from moisture and physical damage.

Back Sheet

The back sheet of solar panels serves as a protective layer at the rear of the panel. This sheet is usually made of a durable and weather-resistant material. It ensures the structural integrity of the panel and provides electrical insulation.

Frame

The metal frame, which is usually made from aluminum, surrounds the solar panel and provides structural support. It also makes it easier to mount the panel on a roof or other surface.

Junction Box

The junction box is attached to the back of the panels and contains the electric connections and diodes. They are responsible for managing the flow of electricity from the solar cells to the external circuit.

Final Thoughts

Solar energy has proven to be a more cost-effective and environment-friendly source of electricity as compared to fossil fuels. That’s why the adaptability of solar power has seen a huge uplift in recent years. It’s also true that the initial investment of installing a solar power plant is a bit higher, but the solar panel price is declining year after year, and in just a few years, you might witness homes, businesses, government institutions, schools, and hospitals rely entirely on rooftop solar panels for powering electrical appliances.