How Solar Panels Work

Solar panels are made of semiconductor materials. They use photoelectric materials to absorb light energy and convert it into photoelectric energy to generate electric current.

How do solar panels work?

Solar panels work by converting sunlight into electricity, a process that uses the sun’s natural energy to power homes, businesses, and more. Here’s how it works:

1. Solar cells capture sunlight

• Solar panels are made up of photovoltaic (PV) cells.
• These cells are made of semiconductor materials (usually silicon) that absorb sunlight.
• When sunlight hits a photovoltaic cell, it knocks electrons off their atoms, creating an electric current.

2. Generation of direct current

• The free flow of electrons produces direct current (DC).
• In direct current, the flow of charge is unidirectional.

3. Convert to usable alternating current (AC)

• Since most homes and appliances run on alternating current (AC), conversion to DC is required.
• A device called an inverter converts direct current into alternating current, allowing the electricity to power your home or business.

4. Electricity use or storage

• Once converted to AC, the energy can be immediately used to power devices around the home.
• Excess electricity can be stored in batteries, or through net metering , for later use.

5. Ongoing solar energy production

• As long as the sun is shining, solar panels will continue to generate electricity.
• Even on cloudy days, solar panels can still produce some energy, although their efficiency will be reduced.

This simple process enables solar panels to provide a clean, renewable source of electricity for a wide range of applications.

What are solar panels made of?

Solar panels are mainly composed of several key components, each of which plays a vital role in the process of converting sunlight into electricity. Here is a breakdown of the main materials used in solar panels:

1. Photovoltaic (PV) cells

• Materials : Silicon (the most common semiconductor material).
• Function : Photovoltaic cells are responsible for converting sunlight into electrical energy through the photovoltaic effect.
  • Monocrystalline silicon : Made of single crystal silicon, it has high efficiency and high durability.
  • Polycrystalline silicon : Made from multiple silicon crystals, it is slightly less efficient but more cost-effective.

2. Glass

• Material : Tempered Glass.
• Function : Protects photovoltaic cells from environmental damage such as hail, debris and weather. It is designed to be extremely durable and transparent to allow sunlight to pass through easily.

3. Sealant

• Material : Ethylene Vinyl Acetate (EVA).
• Function : This is the protective layer that encapsulates the photovoltaic cell and holds it in place. It also provides insulation and protects the cell from moisture, vibration, and physical stress.

4. Negatives

• Materials : Typically polymer based.
• Function : The backsheet provides structural support and protection for the internal components of the solar panel. It prevents water and other contaminants from entering the interior.

5. Border

• Material : Usually made of anodized aluminum.
• Function : The frame holds the solar panels together and provides mounting points. It also adds structural strength to withstand wind, snow and other outdoor conditions.

6. Wire

• Material : Thin strips of metal, usually silver or copper.
• Function : These conductors connect photovoltaic cells and allow electrical current to flow. They collect and transmit the electrical energy generated by the cells.

7. Junction Box

• Material : Durable plastic or metal housing.
• Function : The junction box is where the electrical connections are mounted. It also contains diodes to prevent backflow of current when the panels are not generating electricity, such as at night.

Together, these components make up durable, efficient solar panels that capture sunlight and convert it into usable electricity for homes, businesses and other applications.

What are the mainstream solar technologies?

Mainstream solar technologies that convert sunlight into electricity or heat can be divided into three main types:

1. Photovoltaic (PV) solar technology

• How it works : Photovoltaic solar panels convert sunlight directly into electricity using semiconductor materials (usually silicon) that work in a way that creates the photoelectric effect . When light hits a photovoltaic cell, electrons are knocked off, creating an electric current.
• Main types :
  • Monocrystalline Silicon (Mono-Si) : Made from a single crystal of silicon, it is more efficient and durable. It is widely considered the most efficient and durable photovoltaic technology.
  • Polycrystalline silicon (Poly-Si) : This type of silicon crystal is made of multiple silicon crystals and is cheaper, but slightly less efficient than single crystal silicon.
  • Thin-film solar cells: Made up of much thinner layers of semiconductor material than traditional silicon cells. They are more flexible and lighter, but generally less efficient.
    • Examples : Cadmium telluride (CdTe), copper indium gallium selenide (CIGS), amorphous silicon (a-Si).

2. Concentrated Solar Power (CSP) Technology

• How it works : CSP systems use mirrors or lenses to focus sunlight onto a small area, usually a receiver. The concentrated sunlight is then used to heat a fluid, creating steam to drive a turbine and generate electricity. Unlike PV systems, CSP works by converting sunlight into thermal energy (heat), which can then be used to generate electricity.
• Main types :
  • Parabolic trough : Curved mirrors focus sunlight onto a tube containing a heat-absorbing fluid, producing steam that drives a turbine.
  • Solar tower : Mirrors concentrate sunlight onto a central tower where receivers heat a fluid to produce steam and electricity.
  • Linear Fresnel Reflector : Similar to a parabolic trough, but uses a flat mirror to concentrate sunlight onto a receiver.
  • Dish Stirling system : A parabolic mirror focuses sunlight onto a Stirling engine, generating mechanical power that drives a generator.

3. Solar thermal technology

• How it works : Solar thermal systems capture sunlight to produce heat, which can be used for residential and industrial purposes, such as water heating or space heating.
• Main types :
  • Solar water heaters : Use rooftop collectors to absorb sunlight and heat water for home use.
  • Solar space heating systems : Use solar collectors to capture heat and distribute it throughout a building through an air or water system.
  • Solar Cooling : Converting solar energy into heat can power cooling systems such as absorption chillers.

Emerging Technologies

• Bifacial solar panels : These panels can capture sunlight from both sides, increasing their energy production.
• Perovskite solar cells : A newer and highly promising photovoltaic technology that uses a specific crystal structure called perovskite, with the potential for higher efficiency and lower production costs than traditional silicon-based panels.
• Building-integrated photovoltaics (BIPV) : Solar materials are integrated directly into building components, such as windows or roofs, allowing buildings to generate electricity without traditional solar panels.

These technologies offer a broad range of solutions for generating clean, renewable energy, each suited to different applications, environments and energy needs.