Answer: Solar PV Panel Installation and Working Principle
Solar Photovoltaic (PV) Technology converts sunlight directly into electricity using semiconductor materials. PV cells produce direct current (DC) electricity when photons from sunlight knock electrons free from atoms in the semiconductor material, typically silicon.
Working Principle of Solar PV
The Photovoltaic Effect
The photovoltaic effect is the fundamental principle behind solar PV operation:
- Light Absorption: Sunlight (photons) strikes the PV cell surface
- Electron Excitation: Photon energy is absorbed by electrons in the semiconductor (silicon), giving them enough energy to break free from their atoms
- Electron-Hole Pairs: Free electrons leave behind "holes" (positive charges)
- Electric Field: The p-n junction (doped silicon layers) creates an internal electric field that separates electrons and holes
- Current Flow: Electrons flow through an external circuit, creating electric current (DC)
- Circuit Completion: Electrons return to fill holes, completing the circuit
Structure of a PV Cell
| Layer |
Material |
Function |
| Anti-Reflective Coating |
Silicon Nitride |
Reduces light reflection, increases absorption |
| Front Contact |
Silver grid |
Collects electrons (negative terminal) |
| N-type Silicon |
Phosphorus-doped silicon |
Excess electrons (negative charge) |
| P-N Junction |
Junction zone |
Creates electric field, separates charges |
| P-type Silicon |
Boron-doped silicon |
Excess holes (positive charge) |
| Back Contact |
Aluminum |
Completes circuit (positive terminal) |
Types of Solar PV Cells
| Type |
Efficiency |
Cost |
Applications |
| Monocrystalline |
18-22% |
High |
Rooftops, space-limited areas |
| Polycrystalline |
15-18% |
Medium |
Ground-mount, utility-scale |
| Thin-Film |
10-13% |
Low |
BIPV, flexible applications |
| Bifacial |
20-25% |
High |
Ground-mount with reflective surface |
Components of Solar PV System
- Solar Panels (Modules): Multiple PV cells connected in series/parallel
- Mounting Structure: Fixed-tilt or tracking systems to hold panels
- Inverter: Converts DC to AC power for grid/appliances
- Charge Controller: Regulates battery charging (off-grid systems)
- Battery Bank: Energy storage for off-grid/hybrid systems
- Net Meter: Measures energy exported to grid
- Cables and Connectors: DC and AC wiring
- Protection Devices: MCBs, surge protectors, earthing
Installation Process
1. Site Assessment
- Evaluate solar irradiance (5-7 kWh/m²/day in India)
- Check shading analysis - avoid shadows from trees, buildings
- Assess roof condition - structural strength, age, orientation
- Determine available area - 10 m²/kW for rooftop
- Calculate energy requirement from electricity bills
2. System Design
- Size system based on energy needs and budget
- Select panel type, inverter rating, array configuration
- Design wiring layout and protection scheme
- Determine tilt angle (latitude angle for optimal output)
- Choose orientation (south-facing in Northern Hemisphere)
3. Mounting Structure Installation
- Rooftop: Install rails and clamps on roof surface
- Ground-mount: Concrete foundations, steel structures
- Ensure proper tilt angle (15-25° in India)
- Allow adequate ventilation beneath panels
4. Panel Installation
- Mount panels securely on structure
- Connect panels in series strings for voltage
- Connect strings in parallel for current
- Use MC4 connectors for inter-panel connections
5. Electrical Installation
- Run DC cables from array to inverter (junction box)
- Install inverter in shaded, ventilated location
- Connect AC output to distribution board
- Install net meter for grid-tied systems
- Provide proper earthing and protection
6. Testing and Commissioning
- Check all connections and polarity
- Measure open-circuit voltage and short-circuit current
- Test inverter operation and grid synchronization
- Commission net meter with utility
- Document performance parameters
Installation Costs (India 2024): Rooftop: ₹45,000-55,000/kW | Utility-scale: ₹35,000-45,000/kW | Government subsidies: 40% for residential ≤3 kW
System Types
| Type |
Components |
Application |
| Grid-Tied |
Panels + Inverter + Net Meter |
Urban rooftops, utility plants |
| Off-Grid |
Panels + Charge Controller + Battery + Inverter |
Remote areas, no grid access |
| Hybrid |
Grid-tied + Battery backup |
Areas with unreliable grid |
Conclusion
Solar PV technology works on the photovoltaic effect, where semiconductor materials (silicon) convert sunlight directly into electricity. Installation involves site assessment, system design, mounting structure erection, panel installation, electrical wiring, and commissioning. With declining costs (90% drop in a decade), solar PV is now the cheapest electricity source in many regions. India's ambitious target of 280 GW solar by 2030 makes understanding PV installation and operation essential for the country's clean energy transition.
Sources: Module 2 & 4 Notes | MNRE | SECI | IEA