Photovoltaic (PV)
Photovoltaic (PV) technology converts sunlight directly into electricity through the photoelectric effect in semiconductor materials, most commonly crystalline silicon. The term "photovoltaic" combines the Greek word for light (photo) with the name of Alessandro Volta, the pioneer of electrical science.
When photons of light strike a PV cell, they transfer energy to electrons in the semiconductor, causing them to flow as electric current. This direct conversion of light to electricity — without any moving parts or heat cycles — makes PV systems highly reliable and low-maintenance compared to fossil fuel or even concentrating solar power plants.
PV Cell Types
Monocrystalline silicon: Cut from a single silicon crystal, achieving 19–24% efficiency. Highest efficiency and longest-established technology. Premium cost.
Polycrystalline silicon: Made from multiple silicon crystals; slightly lower efficiency (16–18%) at lower cost. Now being phased out in favor of monocrystalline.
Thin-film (CdTe, CIGS): Deposited on glass or flexible substrates; 10–18% efficiency; lower cost per watt for large utility installations (First Solar's CdTe is a major utility-scale technology).
Passivated Emitter Rear Cell (PERC): An enhanced monocrystalline technology that adds a rear reflective layer, increasing efficiency to 21–23%. Now the dominant technology for new residential and commercial projects.
PV System Components
A complete PV system includes:
- Solar panels (modules): Convert sunlight to DC electricity
- Inverter(s): Convert DC to grid-compatible AC electricity
- Racking/mounting: Structural system supporting panels
- Wiring and combiner boxes: Electrical infrastructure
- Monitoring system: Tracks production and performance
- Battery storage (optional): Stores excess energy