What is solar energy?
Solar energy, the thermal radiant energy of the sun (see the three ways in which thermal energy travels: radiation), is mainly manifested in what is often called the sun's rays. Broadly speaking, solar energy is the source of many energy sources on Earth, such as wind energy, chemical energy, potential energy of water, etc.
How Solar Panels Work: The Photovoltaic Effect
Solar panels work by generating electricity when sunlight particles or photons release electrons from atoms and set them in motion. This flow of electrons is electricity, and solar panels are designed to capture this flow of electrons and convert it into a usable electric current. This process is called the photovoltaic effect and is the underlying chemical and physical process behind the vast majority of solar technologies.
Steps in which the photovoltaic effect works.
2. When an N-type semiconductor is combined with a P-type semiconductor, the free electrons in the N-type semiconductor and the holes in the P-type semiconductor will diffuse and combine with each other until they reach a dynamic equilibrium, a stable state called a PN junction. In the built-in electric field, the direction of electron motion is directed from the N-type semiconductor to the P-type semiconductor.
3. When sunlight hits a photovoltaic cell, the photon energy in the light is absorbed by some of the electrons. When the energy absorbed by the electron is large enough, it can break away from the covalent bond and become a free electron. Accordingly, a hole is formed, and the electron and hole will move to N area and P area respectively under the electric field force of the built-in electric field, under the continuous irradiation of sunlight, the electron and hole accumulate in N area and P area respectively, thus forming an electric potential difference, making N area negatively charged and P area positively charged, which we call "photogenerated electric field", at this time the The direction of electron motion is from the P region to the N region. At this point, if the external circuit is connected, the electrons accumulated in the N area will return to the P area through the circuit, thus generating current.
How can solar panels generate electricity for your home?
Photovoltaic cells are sandwiched between layers of semiconductor materials such as silicon. Each layer has different electronic properties that generate energy when hit by photons from the sun, creating an electric field.
Generating an electric current is the first step in how solar panels work, and here's how solar panels can create a usable electrical system for your home..
1. Photovoltaic cells absorb the sun's energy and convert it to direct current
As mentioned above, the solar cells that make up each solar panel do a lot of work in actually generating electricity. Two layers of silicon are used in a photovoltaic cell, and each layer is specially treated or "doped" to create an electric field at the junction between the layers. This electric field forces loose electrons to flow through the solar cell and out of the silicon junction, creating an electric current. Through the photovoltaic effect, the solar panel generates an electric current.
2. The solar inverter converts the direct current from the solar module into alternating current, which is used by most household appliances. When DC power passes through a solar inverter, it is converted to AC power. Inverters can also be equipped with transformers that regulate the voltage of DC and AC currents.
3. Electricity flows through your home to power electronic devices
The solar inverter transmits the converted AC power to your home's electrical panel. From there, the power is dispersed through your house to all the outlets so there is available current when your devices need to be plugged in.
4. Excess electricity generated by solar panels is fed to the grid
If you have a grid-connected solar system, electricity can flow both into and out of the grid, and the excess energy produced by your panels can actually make you money. Through a policy called net metering, you get a credit from the grid when you send electricity back to the grid, which makes your overall electricity bill cheaper.