Solar Panels Grants

Residential solar panels, like their commercial counterparts, convert sunlight directly into electricity using the photovoltaic (PV) effect. This process involves several key components and steps:

1. Photovoltaic Effect

The photovoltaic effect, discovered by Edmond Becquerel in 1839, is the fundamental principle behind solar panels. This effect occurs when photons (light particles) strike a semiconductor material, causing electrons to be knocked loose and creating an electric current.

2. Semiconductor Materials

Silicon is the most common semiconductor material used in residential solar panels. Silicon atoms are arranged in a crystal lattice (a crystal lattice is a three-dimensional, repeating arrangement of atoms, ions, or molecules in a crystalline material, characterised by its unit cell and symmetry), which facilitates the movement of electrons when energised by sunlight.

3. Solar Cell Structure

A solar panel is composed of multiple solar cells. Each cell consists of a silicon wafer that has been doped with impurities to create a p-n junction. This p-n junction is crucial for creating an electric field that separates electrons and holes (positive charges), generating an electric current.

What is a p-n Junction?

A p-n junction is a boundary or interface between two types of semiconductor materials inside a solar cell. These materials are called p-type and n-type silicon.

• P-type Silicon: This type of silicon is created by adding a small amount of another element (like boron) to the silicon. This process is called doping. P-type silicon has more positive charges (called “holes”) because it has fewer electrons than pure silicon.
• N-type Silicon: This type of silicon is also created by doping, but with an element like phosphorus. N-type silicon has more electrons than pure silicon, which means it has more negative charges.

Creating the p-n Junction

When you place p-type silicon (positive) and n-type silicon (negative) together, they form a p-n junction. At this junction, something interesting happens:

• Diffusion: Electrons from the n-type silicon move to the p-type silicon to fill the holes. Similarly, holes from the p-type silicon move to the n-type silicon to balance the extra electrons.
• Depletion Zone: As electrons and holes move across the junction, they leave behind charged ions. This movement creates a region around the junction where there are no free electrons or holes, called the depletion zone.

Electric Field Creation

The depletion zone creates an electric field because it has positively charged ions on the n-type side and negatively charged ions on the p-type side. This electric field is crucial because it acts like a barrier that prevents more electrons and holes from moving across the junction.

How the p-n Junction Generates Electric Current

• Sunlight Hits the Solar Cell: When sunlight, which contains photons (light particles), hits the solar cell, it provides enough energy to knock electrons free from the atoms in the silicon.
• Separation of Electrons and Holes: The electric field in the depletion zone pushes the freed electrons towards the n-type side and the holes towards the p-type side.
• Electric Current: The movement of electrons to the n-type side and holes to the p-type side creates a flow of electric charge. When these electrons are collected by metal contacts on the surface of the solar cell, they can flow through an external circuit, creating an electric current. This current can then be used to power electrical devices or charge batteries.

Simple Analogy

Imagine the p-n junction as a slide at a playground. The top of the slide (n-type side) has lots of kids (electrons), and the bottom of the slide (p-type side) has lots of empty spots (holes). When the kids go down the slide, they fill the empty spots. The slide (depletion zone) stops more kids from going down and creates a separation. When sunlight shines, it gives energy to the kids (electrons) at the top, pushing them down the slide to create a flow of kids (electric current) towards the bottom (p-type side).

In summary, the p-n junction is essential because it creates an electric field that separates electrons and holes when sunlight hits the solar cell. This separation is what generates an electric current, allowing the solar panel to produce electricity.

4. Electric Field Created

This current is then collected by thin metal strips, known as busbars, and transferred through wires to form a complete circuit.

5. Inverters and Electrical Systems

The direct current (DC) generated by solar panels is converted into alternating current (AC) by an inverter, as most household appliances and the electrical grid operate on AC. The difference between AC (Alternating Current) and DC (Direct Current) lies in the direction of the flow of electric charge:

1.   AC (Alternating Current):

      •   The electric charge (current) periodically reverses direction.
      •   The voltage level also varies with time.
      •   AC is commonly used for power supply in homes and industries.
      •   Example: Household outlets typically supply AC.

2.   DC (Direct Current):

      •   The electric charge flows in a single direction.
      •   The voltage level remains constant over time.
      •   DC is commonly used in battery-powered devices and electronics.
      •   Example: Batteries and solar panels provide DC.

Basically, AC changes direction periodically, while DC flows in one constant direction.

Ultimately, the inverter plays a crucial role in ensuring that the electricity generated is compatible with the existing electrical infrastructure i.e. converting from DC to AC.

6. Energy Storage and Distribution

Excess energy generated by residential solar panels can be stored in batteries for later use or fed back into the grid. This is called net metering and net metering systems allow homeowners to earn credits for the surplus energy they supply to the grid, offsetting their electricity bills.

Types of Residential Solar Panels

Residential solar panels come in various types, each with its unique characteristics, efficiencies, and applications. The main types are monocrystalline, polycrystalline, thin-film, bifacial, and building-integrated photovoltaics (BIPV). Those fitted on the ECO4 scheme tend to be monocrystalline and more recently, bifacial.

1. Monocrystalline Solar Panels

Structure and Composition

Monocrystalline are the most commonly installed panels funded through solar panels grants. Monocrystalline panels are made from single-crystal silicon wafers. These wafers are cut from cylindrical silicon ingots, resulting in a uniform and high-purity crystal structure.

Efficiency

Monocrystalline panels are known for their high efficiency, typically ranging from 15% to 20%. That is to say that the solar panels can convert 15% to 20% of the sunlight that hits them into usable electrical energy. This is because their uniform crystal structure allows for better electron flow, resulting in higher energy conversion rates.

Advantages

•  High Efficiency: Monocrystalline panels have the highest efficiency among the different types of solar panels, making them suitable for limited space applications.
•  Durability: They have a longer lifespan, often exceeding 25 years, due to their high-quality materials.
•  Aesthetic Appeal: These panels have a sleek black appearance, making them more visually appealing for residential installations.

Disadvantages

•  Cost: Monocrystalline panels are more expensive to manufacture, resulting in higher upfront costs.
•  Performance in Shading: Their performance can be significantly affected by shading, as a shaded portion of a cell can reduce the output of the entire panel.

2. Polycrystalline Solar Panels

Structure and Composition

Polycrystalline panels are made from silicon fragments melted together to form wafers. These wafers are then cut into square shapes, resulting in a less uniform crystal structure compared to monocrystalline panels.

Efficiency

Polycrystalline panels have slightly lower efficiency, typically ranging from 13% to 16%. The irregular crystal structure causes more resistance to electron flow.

Advantages

•  Cost-Effective: Polycrystalline panels are cheaper to produce, making them a more affordable option for residential installations.
•  Environmental Impact: The manufacturing process produces less waste silicon compared to monocrystalline panels.
•  Performance in Heat: These panels tend to perform better in high-temperature conditions compared to monocrystalline panels.

Disadvantages

•  Lower Efficiency: The efficiency is lower, requiring more space to generate the same amount of power as monocrystalline panels.
•  Aesthetic Appeal: They have a blueish hue and a less uniform appearance, which some find less attractive.

3. Thin-Film Solar Panels

Structure and Composition

Thin-film panels are made by depositing one or more layers of photovoltaic material onto a substrate, such as glass, plastic, or metal. The most common materials used are cadmium telluride (CdTe), amorphous silicon (a-Si), and copper indium gallium selenide (CIGS).

Efficiency

Thin-film panels have lower efficiency, typically ranging from 10% to 12%. However, advancements in technology are gradually improving their efficiency.

Advantages

•  Flexibility: Thin-film panels can be made flexible, allowing for a variety of applications, including integration into building materials.
•  Performance in Low Light: They perform better in low-light conditions and partial shading compared to crystalline silicon panels.
•  Cost: The manufacturing process is simpler and less expensive, making thin-film panels a cost-effective option for certain applications.

Disadvantages

•  Lower Efficiency: Their lower efficiency requires more space to generate the same amount of power as crystalline silicon panels.
•  Lifespan: Thin-film panels typically have a shorter lifespan and may degrade faster over time.

4. Bifacial Solar Panels

Structure and Composition
Bifacial panels are designed to capture sunlight from both sides of the panel. They typically have a transparent back-sheet or a dual-glass design, allowing light to enter from the rear and be absorbed by the solar cells. Bifacial is the newest type of panel installed via solar panels grants on the ECO4 scheme.

Efficiency
Bifacial panels can achieve higher overall efficiency by utilising reflected and diffused light from the surroundings. Their efficiency can be up to 11% higher than traditional single-sided panels.

Advantages

•  Increased Energy Yield: By capturing light from both sides, bifacial panels can generate more electricity, especially when installed on reflective surfaces.
•  Durability: The dual-glass design enhances durability and resistance to environmental factors.
•  Versatility: These panels can be used in various installations, including ground-mounted systems, rooftops, and solar canopies.

Disadvantages

•  Cost: Bifacial panels are more expensive due to the additional materials and manufacturing processes involved.
•  Installation Complexity: Proper installation is required to maximise the benefits, including considerations for albedo (reflectivity) of the installation surface.

5. Building-Integrated Photovoltaics (BIPV)

Structure and Composition
BIPV systems integrate solar panels into building materials, such as roofs, facades, and windows. These panels serve dual purposes, acting both as building materials and energy generators.

Efficiency
The efficiency of BIPV systems varies depending on the specific materials and design used. Generally, they offer slightly lower efficiency compared to traditional PV panels due to their integration into building structures.

Advantages

•  Aesthetic Integration: BIPV systems blend seamlessly into the architecture of buildings, enhancing aesthetic appeal.
•  Space Utilisation: By integrating into building materials, BIPV systems utilise space efficiently, making them ideal for urban environments.
•  Functionality: They provide both energy generation and structural functions, such as insulation and weather protection.

Disadvantages

•  Cost: BIPV systems can be more expensive to install due to the dual-function materials and specialised installation processes.
•  Efficiency: The efficiency of BIPV panels may be lower than standalone solar panels due to design constraints and integration challenges.

Factors Influencing the Choice of Residential Solar Panels

With Solar Panels grants available for many residents in the UK, there are several factors to be considered to ensure the best fit for the resident’s specific needs and circumstances:

1. Efficiency and Space Constraints

For homes with limited roof space, high-efficiency panels like monocrystalline or bifacial may be preferred to maximise power output.

2. Cost and Budget

Budget constraints play a significant role in the choice of solar panels. Polycrystalline or thin-film panels may be chosen for their lower upfront costs, by residents who are funding the work themselves, despite their lower efficiency. However, Fairway Energy Ltd use the highest quality and best performing solar panels for residential premises, such as monocrystalline or bifacial.

3. Aesthetic Preferences

Aesthetic considerations can influence the choice of solar panels. Monocrystalline panels are often preferred for their sleek black appearance, while BIPV systems offer an integrated look that blends with the building’s architecture. However, BIPV systems are not fitted in a retrofit installation and are primarily used in new build projects.

4. Environmental Conditions

The local climate and environmental conditions can affect the performance of different types of solar panels. Polycrystalline panels may be more suitable for high-temperature regions such as in the middle east or tropical climates.

5. Installation Type

The type of installation, whether rooftop, ground-mounted, or integrated into building materials, can influence the choice of solar panel. Bifacial panels and monocrystalline are usually best for residential retrofit, whereas BIPV systems offer unique advantages for new build commercial installation scenarios.

Advancements in Residential Solar Panel Technology

The solar industry is continuously evolving, with ongoing research and development aimed at improving efficiency, reducing costs, and expanding applications. Although not currently available through ECO4, some notable advancements in residential solar panel technology include:

1. Perovskite Solar Cells

Perovskite materials have shown great potential for high efficiency and low-cost production. They can be used in tandem with silicon cells to create hybrid panels with even higher efficiency.

2. Organic Photovoltaics (OPV)

OPV technology uses organic materials to create flexible and lightweight solar panels. These panels can be integrated into a variety of surfaces, including clothing and portable devices.

3. Solar Shingles

Solar shingles are a type of BIPV that integrates seamlessly with traditional roofing materials. They offer an aesthetically pleasing alternative to conventional solar panels while generating electricity.

4. Energy Storage Integration

Advancements in energy storage technology, such as lithium-ion batteries, are enhancing the capabilities of residential solar systems. This is because integrated storage solutions allow homeowners to store excess energy for use during nighttime or power outages.

Residential solar panels are at the forefront of the renewable energy revolution, offering homeowners a sustainable and cost-effective way to generate electricity. That’s why understanding how solar panels work and the different types available is crucial for making informed decisions about your solar panel installation.

From the high efficiency of monocrystalline panels to the versatility of thin-film and bifacial panels, each type has unique advantages that cater to different needs, preferences and environments. As technology continues to advance, the future of residential solar energy looks promising, with ongoing improvements in efficiency, cost-effectiveness, and integration into everyday life. Therefore, by embracing solar energy, you can contribute to a greener, more sustainable future while also enjoying the financial and environmental benefits of renewable energy solutions.

Solar Panels Grants Available. Apply Now!