How Do Solar Panels Work?
Solar panels convert sunlight directly into electricity using the photovoltaic effect. When photons (light particles) hit silicon cells in the panel, they knock electrons loose from atoms. The cell's structure creates an electric field that directs these electrons to flow in one direction, creating an electric current. This DC power is then converted to AC for home use.
Key Takeaways
- Solar cells are made of semiconductor materials, typically silicon.
- Efficiency is typically 15-22% for residential panels - most sunlight energy is lost as heat.
- Cloudy days reduce but do not eliminate power generation.
Explanation
Solar cells are made of semiconductor materials, typically silicon. The silicon is treated (doped) to create two layers: one with extra electrons (n-type) and one with missing electrons called holes (p-type). Where these layers meet, an electric field forms that acts like a one-way gate for electrons.
When sunlight hits the cell, photons transfer their energy to electrons, freeing them from their atoms. The electric field at the junction pushes these freed electrons toward the n-type layer and holes toward the p-type layer. Metal contacts on the cells collect the electrons, creating an electric current when connected to a circuit.
The direct current (DC) produced by solar panels must be converted to alternating current (AC) for home use. An inverter handles this conversion. In grid-tied systems, excess power feeds back to the utility grid. Battery systems can store power for use when the sun is not shining.
Things to Know
- Efficiency is typically 15-22% for residential panels - most sunlight energy is lost as heat.
- Cloudy days reduce but do not eliminate power generation.
- Concentrated solar power uses mirrors to heat fluid and generate electricity differently from photovoltaics.