Solar energy is collected through two primary methods: photovoltaic (PV) panels and concentrated solar power (CSP) systems.
Photovoltaic (PV) Panels
PV panels, also known as solar panels, directly convert sunlight into electricity using the photovoltaic effect.
- Semiconductor Material: PV cells are made of semiconductor materials, typically silicon. When sunlight strikes the cell, photons (light particles) excite electrons in the silicon.
- Electron Flow: This excitation causes electrons to break free from their atoms and flow through an electrical circuit, generating electricity.
- Direct Conversion: The electricity produced is direct current (DC), which can be used directly or converted to alternating current (AC) using an inverter for use in homes and businesses.
Concentrated Solar Power (CSP)
CSP systems use mirrors or lenses to concentrate a large area of sunlight onto a small area. This concentrated heat is then used to generate electricity.
- Mirrors/Lenses: Large arrays of mirrors (heliostats) or lenses focus sunlight onto a receiver.
- Heat Transfer: The concentrated sunlight heats a working fluid (e.g., water, oil, or molten salt) to high temperatures.
- Electricity Generation: The heated fluid is used to produce steam, which drives a turbine connected to a generator, producing electricity.
- Thermal Storage: Some CSP plants incorporate thermal energy storage, allowing them to generate electricity even when the sun isn't shining.
In summary, solar energy is collected either by directly converting sunlight to electricity via PV panels or by concentrating sunlight to generate heat, which is then used to produce electricity through conventional turbine-based systems.
