Solar panels might seem like magic—sunlight hits them and electricity comes out. But the science is straightforward once you understand the basics. Here's how solar panels convert sunlight into power for your home.
The Photovoltaic Effect
Solar panels work through the photovoltaic (PV) effect, discovered in 1839 by French physicist Edmond Becquerel.
How It Works
- Sunlight hits the panel: Solar energy arrives as photons (light particles)
- Photons energise electrons: When photons strike silicon cells, they knock electrons loose
- Electrons flow: The cell's electric field pushes electrons in one direction
- Current is created: This flow of electrons is electricity
Inside a Solar Cell
Each solar cell contains:
| Layer | Material | Purpose |
|---|---|---|
| Top layer | N-type silicon | Has extra electrons |
| Junction | Electric field | Directs electron flow |
| Bottom layer | P-type silicon | Has "holes" for electrons |
| Contacts | Metal strips | Collect the electricity |
From Cell to System
Solar Cells
- The basic unit of electricity generation
- Each cell produces about 0.5 volts
- Made from silicon wafers (typically 166mm or 182mm)
- Modern cells achieve 22-24% efficiency
Solar Panels (Modules)
- Multiple cells wired together (60-72 cells typical)
- Glass, frame, and backing protect the cells
- Standard panels produce 400-550 watts
- Connected in "strings" for higher voltage
Solar Arrays
- Multiple panels connected together
- A typical home uses 12-24 panels
- Total output measured in kilowatts (kW)
Types of Solar Cells
Monocrystalline (Dominant)
Made from single silicon crystals:
- Highest efficiency (22-24%+)
- Best performance in heat
- Longest lifespan (30-40 years)
- Premium appearance (uniform black)
- Most common choice in 2026
N-Type vs P-Type
Modern panels use N-type technology:
| Feature | P-Type | N-Type |
|---|---|---|
| Efficiency | 20-22% | 22-24%+ |
| Degradation | 0.5%/year | 0.3%/year |
| Heat tolerance | Standard | Better |
| Light capture | One side | Bifacial capable |
| Cost | Lower | Slightly higher |
Polycrystalline (Phased Out)
- Made from multiple silicon fragments
- Lower efficiency (18-20%)
- Blue, speckled appearance
- No longer manufactured (0% of production in 2026)
Thin-Film
- Flexible, lightweight
- Lower efficiency (10-13%)
- Used in specific applications (BIPV, portable)
- Not common for residential rooftops
The Role of Inverters
Solar panels produce direct current (DC), but your home uses alternating current (AC). Inverters convert DC to AC.
String Inverters
Most common type:
- One inverter for entire system
- Panels wired in "strings"
- Cost-effective and reliable
- Best for unshaded roofs
Popular brands: Fronius, Sungrow, SMA
Microinverters
Individual inverter per panel:
- Each panel operates independently
- Better for shaded or complex roofs
- Panel-level monitoring
- Higher initial cost, longer warranty
Popular brand: Enphase (25-year warranty)
Hybrid Inverters
Combines solar and battery functions:
- Manages solar, battery, and grid
- Allows battery addition later
- Backup power capability
- Growing in popularity
Popular brands: Sungrow, GoodWe, Fronius GEN24
Connecting to the Grid
How Grid Connection Works
- Solar generates power: Panels produce electricity
- Inverter converts: DC becomes AC
- Home uses power: Appliances consume electricity
- Excess exports: Unused power goes to grid
- Meter records: Bidirectional meter tracks import/export
- Credits earned: You receive feed-in tariff for exports
Metering Explained
| Meter Type | What It Measures |
|---|---|
| Import | Electricity from grid |
| Export | Solar sent to grid |
| Net | Difference (import - export) |
| Gross | All solar generated (rare in VIC) |
Victoria uses net metering—you're credited for exports and charged for imports.
How Much Electricity Do Panels Produce?
Factors Affecting Output
| Factor | Impact |
|---|---|
| Panel wattage | Higher watts = more power |
| Sun hours | More sun = more generation |
| Roof orientation | North-facing is ideal |
| Roof tilt | ~30° optimal for Victoria |
| Shading | Any shade reduces output |
| Temperature | Hot panels are less efficient |
| Panel age | Slight decrease over time |
Typical Generation
A 6.6 kW system in Melbourne produces:
- Daily average: 24-28 kWh
- Summer day: 35-40 kWh
- Winter day: 15-18 kWh
- Annual total: 9,000-10,000 kWh
Efficiency Explained
Solar panel efficiency measures how much sunlight becomes electricity.
Current Efficiency Levels
| Panel Type | Efficiency | Result (6.6kW system) |
|---|---|---|
| Budget | 18-20% | 8,500 kWh/year |
| Standard | 20-22% | 9,200 kWh/year |
| Premium | 22-24%+ | 10,000 kWh/year |
Why Efficiency Matters
Higher efficiency means:
- More power from same roof space
- Better performance in partial shade
- Improved heat tolerance
- Often better warranty terms
Temperature and Performance
Solar panels perform better when cool—counterintuitively, they're most efficient on cool sunny days, not hot ones.
Temperature Coefficient
This measures efficiency loss as temperature rises:
| Panel Quality | Coefficient | Loss at 45°C |
|---|---|---|
| Standard P-type | -0.40%/°C | 8% loss |
| Premium N-type | -0.30%/°C | 6% loss |
| Best in class | -0.26%/°C | 5.2% loss |
Why Victoria Is Good for Solar
- Cool mornings maximise efficiency
- Sea breezes help coastal panels
- Summer heat balanced by long days
- Winter sun is valuable (panels stay cool)
What Happens at Night?
Solar panels only work with light, so at night:
- Without battery: You draw from the grid
- With battery: Stored energy powers your home
- Smart approach: Use heavy appliances during daylight
Common Questions
Do panels work on cloudy days?
Yes, but at reduced output:
- Light overcast: 50-70% of peak
- Heavy clouds: 10-25% of peak
- Diffuse light still generates electricity
Do panels need direct sunlight?
Direct sunlight is best, but panels still generate from:
- Scattered light (cloudy conditions)
- Reflected light
- Morning and afternoon angles
How long do panels last?
Modern panels are built to last:
- 25-30 year performance warranty standard
- Actual lifespan: 30-40 years
- Degradation: 0.3-0.5% efficiency loss per year
The Bottom Line
Solar panels work by converting sunlight directly into electricity through the photovoltaic effect. The process is:
- Sunlight hits silicon cells
- Photons knock electrons loose
- Electric field creates current
- Inverter converts DC to usable AC
- Your home uses the power or exports to grid
With modern N-type monocrystalline panels achieving over 22% efficiency and lasting 30+ years, solar technology has matured into a reliable, cost-effective energy solution.
Contact H.T Electrics and Solar to learn how solar panels can work for your home.
