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Solar panels are revolutionising how we produce and consume electricity, offering an eco-friendly and cost-effective way to power homes and businesses.
In the UK, people worry that we might not get enough sunlight to generate enough energy. This blog breaks down the technology behind solar panels, how they generate electricity, and why they’re an important part of the UK's move towards sustainable energy.
What are Solar Panels?
Solar panels convert sunlight into electricity through a process known as the photovoltaic effect. These panels are often installed on roofs or open fields to capture sunlight throughout the day. Once sunlight hits the panel, it generates electricity that can power homes or businesses. Solar panels are key to the renewable energy transition, providing a clean, green energy source that’s reducing our dependence on fossil fuels.
Solar panels are made up of photovoltaic (PV) cells, commonly called solar cells, that turn sunlight into usable electricity. Typically, these panels are installed at an angle to maximize sunlight exposure. The output of the panel is then connected to an inverter, which converts the electricity into a form that can be used to power your home.
Which types of solar panels are available in the UK
There are different types of solar panels available in the UK, each with its advantages and applications. The choice of panel depends on factors like budget, available space, and energy needs. Here’s a breakdown of the three most common types.
See the types of solar panels we install and recommend.
Monocrystalline Solar Panels
Monocrystalline solar panels are made from a single continuous crystal structure. They’re known for their high efficiency and long lifespan. These panels are more efficient than other types because they’re made from high-purity silicon, allowing them to absorb sunlight more effectively. While they tend to be more expensive, they also offer better performance, especially in limited space.
Polycrystalline Solar Panels
Polycrystalline solar panels are made from silicon crystals that are melted together. They’re generally less efficient than monocrystalline panels, but they are more affordable. While they may take up more space to generate the same amount of electricity, they’re still a popular choice for homeowners who want a cost-effective solar solution.
Thin-Film Solar Panels
Thin-film solar panels are lightweight and flexible, often used in large-scale commercial applications or in spaces where weight is a concern. They’re made by applying a thin layer of photovoltaic material to a surface, such as glass or metal. Although cheaper to make, they tend to be less efficient than crystalline panels, meaning they need more space to generate the same amount of electricity.
The science behind how solar panels work
Solar panels rely on scientific principles to work. Here’s how they function at a molecular and atomic level.
The photovoltaic effect: how solar panels convert sunlight into electricity
The photovoltaic effect is key to solar panel technology. It’s the process where light from the sun is turned into electricity.
Sunlight is made up of tiny particles called "photons." When these photons hit a special material in a solar panel (called a "photovoltaic cell"), they give energy to the atoms in the material. This energy causes the atoms to release tiny particles called "electrons." These free electrons start moving, and when they flow in a certain direction, they create an electric current.
The role of semiconductors in solar panels
Semiconductors are materials that can conduct electricity under certain conditions, making them the ideal choice for solar cells. Silicon is the most commonly used semiconductor in solar panels. It’s typically treated to form two types of layers, positive and negative. This creates an electric field that forces the excited electrons to move in a specific direction, generating an electric current.
How electrons work in solar panels
When sunlight hits the solar cells, it provides energy in the form of photons. These photons knock electrons loose from the atoms in the semiconductor material. The movement of these electrons creates an electric current that can be captured and used. The efficiency of this process depends on the quality of the semiconductor material and the design of the solar cells.
The main parts of a solar panel
Solar panels are made up of several key components. These include the solar cells, glass layers, wiring, and other electrical components.
What are solar cells and how do they work?
Solar cells are the fundamental unit of a solar panel, converting sunlight into electricity. Multiple solar cells are connected together to form a panel, and these cells are typically made of silicon which acts as a semiconductor. Each solar cell generates direct current (DC) electricity, and the rest of the system transforms it into usable power.
The role of glass on solar panels
The glass layer on top of solar panels protects the solar cells from the elements like rain, wind, and dust. It also helps with light transmission, making sure that sunlight can reach the solar cells efficiently. The glass is usually tempered for durability.
The wiring and electrical components in solar panels
Wiring and electrical components, including diodes and junction boxes, are used to connect the solar cells and ensure that the electricity generated flows properly. These components help direct the DC electricity from the solar cells to an inverter, which converts the electricity into alternating current (AC).
How solar panels generate electricity
Once the solar panel absorbs the sunlight through the photovoltaic effect as described above. This energy then needs to be converted into usable electricity.
How solar panels convert direct current to alternating current
Solar panels produce electricity in the form of direct current (DC), meaning the electric charge flows in one direction. The majority of homes, businesses, and the grid operate on alternating current (AC), where the direction of the flow of electricity sometimes reverses. This difference in current types requires an inverter to convert DC electricity from solar panels into AC electricity.
This process is vital. Most household appliances like fridges, lights, and televisions, as well as the electricity grid run on AC power. By converting the DC to AC, the inverter makes sure that the energy produced by the solar panels can be used in homes.
Factors that impact solar panel efficiency in the UK
In the UK, weather conditions can be unpredictable and sunlight hours vary a lot throughout the year. With this in mind, several factors can affect the efficiency of solar panels.
Optimal angle and positioning of solar panels
In the UK, solar panels should be positioned at an optimal angle of 30 to 40 degrees. This helps to make sure that they capture the most sunlight, especially during peak daylight hours. The exact angle can depend on the orientation of your roof, as well as the installation site. South-facing roofs are ideal for solar panel installations, as they receive the most direct sunlight throughout the day. East- and west-facing panels can still be efficient, particularly if the angle of the roof is adjusted to enhance exposure.
Sunlight exposure and seasonality
One of the most significant challenges in the UK is the variability of sunlight across the year. During the winter months, we have less hours of sunlight and more frequent cloudy or rainy days. Because of this, solar panels generate less electricity in winter compared to the summer months. Solar panels still generate energy in overcast conditions, just at a lower capacity. A battery storage system improves the overall performance of solar panels. This allows you to store energy generated during sunny spells for use during cloudy days or at night.
The solar panel material
There are various types of solar panels, including monocrystalline, polycrystalline, and thin-film panels, as mentioned above. Monocrystalline panels are made from a single crystal structure. They are known for their higher efficiency, particularly in low-light conditions. This makes them an excellent choice for the UK’s often overcast weather conditions, where maximising energy production is crucial. Monocrystalline panels are typically more expensive than polycrystalline panels, but the additional cost justifies their higher efficiency and longevity. Polycrystalline panels, while less efficient, are still a good choice if you're on a tighter budget and have lots of roof space for installation. Thin-film solar panels are another option, though they’re generally less efficient and more suited to specific applications.
The impact of dirt, shading, and maintenance
Solar panels need to be kept clean and free from obstructions so that they work at their peak efficiency. Even small amounts of dirt, dust, or debris can reduce the amount of sunlight reaching the panels, lowering their energy output.
Shading from nearby trees, buildings, or other structures can also drastically affect performance. In the UK, where sun exposure can already be limited, it’s especially important to avoid shading whenever possible.
Regular maintenance is essential to ensure optimal performance. This includes cleaning the panels, inspecting for any potential damage, and trimming back any trees or plants that might block sunlight. Additionally, during the winter months, it's importantly to clear snow or ice from the panels, as these can block sunlight and reduce energy generation.