Solar panels convert sunlight into usable electricity for your home, offering a route to lower energy bills and a smaller carbon footprint. For UK homeowners, understanding how this technology functions, especially given our climate, is key to making an informed decision. It is not just about sunny days; solar panels are designed to perform even under typical British weather conditions.
Understanding the basics: the photovoltaic effect
At the heart of every solar panel is the photovoltaic (PV) effect. This is the fundamental scientific principle that allows solar cells to convert light directly into electricity. When photons (particles of light) from the sun strike the semiconductor material, typically silicon, within the PV cells, they excite electrons. These excited electrons are then dislodged from their atoms, creating an electric current.
From sunlight to electricity: the science explained
Each solar panel is made up of multiple PV cells. These cells are designed with positive and negative layers, creating an electric field. When sunlight hits the panel, the photons transfer their energy to the electrons in the silicon, causing them to move and generate a direct current (DC) of electricity. Modern solar panels typically have an efficiency rating between 17% and 20%, meaning they convert that percentage of sunlight into usable electricity.
Direct current (DC) vs alternating current (AC): why it matters
The electricity generated by solar panels is direct current (DC). However, most household appliances and the National Grid operate on alternating current (AC) electricity. This is where a crucial component, the inverter, comes into play. The inverter's job is to convert the DC electricity from your solar panels into AC electricity, making it compatible with your home's electrical system and the wider grid.
Key components of a home solar system
A complete home solar system involves more than just the panels on your roof. Several components work together to ensure your home can generate, use, and manage its own electricity.
Solar panels (PV modules): the energy collectors
These are the most visible part of the system, typically installed on your roof. Each panel contains numerous photovoltaic cells, wired together to produce a collective electrical output. The number of panels you need depends on your energy consumption and available roof space.
Inverters: converting power for your home
As mentioned, the inverter is essential. It is usually located inside your home, often in a garage or utility room, and acts as the brain of your solar system. It continuously monitors the electricity generated by your panels and converts it from DC to AC, ensuring a steady supply of usable power.
Mounting systems and wiring: securing your setup
Solar panels are securely attached to your roof using a robust mounting system. This system is designed to withstand various weather conditions, including strong winds. The panels are then connected via wiring to the inverter, and from there, to your home's consumer unit (fuse box).
Optional: battery storage for greater independence
While not strictly necessary, many homeowners choose to add a battery storage system. This allows you to store any surplus electricity generated by your panels during the day for use later, such as in the evening or on cloudy days. This increases your self-consumption and reduces your reliance on drawing electricity from the National Grid.
The journey of solar electricity in your home
Once installed, your solar panel system follows a clear path for electricity generation and distribution.
Powering your home during the day
When the sun is shining, your solar panels generate DC electricity. This flows to the inverter, which converts it to AC. This AC electricity then prioritises powering your home's appliances directly. If you are generating more electricity than you are using, the surplus can be sent to a battery for storage or exported to the National Grid.
Connecting to the National Grid: import and export
Homes with solar panels remain connected to the National Grid. This connection is vital for two reasons:
Importing electricity: When your solar panels are not generating enough power (e.g., at night or on very cloudy days) and your battery is depleted, your home automatically draws electricity from the National Grid.
Exporting electricity: If your panels generate more electricity than your home needs and your battery is full, the excess is automatically exported to the National Grid. Under the Smart Export Guarantee (SEG), large energy suppliers are mandated to pay customers for this renewable electricity they export.
What happens at night or on cloudy days?
Solar panels continue to generate electricity on cloudy days, albeit at a reduced capacity, as they can still capture diffused sunlight. However, they do not generate electricity at night. During these times, your home will either draw power from your battery storage system (if you have one) or seamlessly switch to importing electricity from the National Grid. This ensures your home always has a reliable power supply.
Do solar panels work in winter?
Yes, solar panels work in winter, though their output is lower due to shorter daylight hours and a lower sun angle. They still convert sunlight into electricity, and modern systems are designed to perform efficiently even in cooler temperatures and when capturing diffused light through cloud cover.
Solar panels in the UK: performance and benefits
The UK's climate might not be famous for its perpetual sunshine, but solar panels are a viable and beneficial investment for many British homeowners.
Generating power in British weather conditions
It is a common misconception that solar panels are ineffective in the UK due to our often cloudy weather. The reality is that solar panels are designed to capture both direct and diffused sunlight. This means they continue to generate electricity even on overcast days, albeit at a lower rate than on bright, sunny days. Performance is reduced in winter due to shorter daylight hours and a lower sun angle, but they still contribute to your home's energy needs year-round.
Maximising your savings and export earnings
Solar panels can significantly reduce your electricity bills by allowing you to generate your own power. The average UK home uses around 2,500 kWh of electricity per year1. By generating a substantial portion of this yourself, you buy less from the grid.
Furthermore, the SEG allows you to earn money for any surplus electricity you export back to the National Grid. This UK government-backed scheme requires licensed electricity suppliers to offer a tariff for your exported power. Choosing an energy supplier with competitive SEG rates and smart tariffs can help you maximise these earnings and further reduce your overall energy costs. Smart energy management, often facilitated by an energy app, allows you to track your generation and consumption, helping you make informed decisions about when to use or store your power to get the most value.
Environmental advantages for UK homeowners
Beyond the financial benefits, installing solar panels offers significant environmental advantages. By generating clean, renewable electricity, you reduce your reliance on fossil fuels and lower your home's carbon emissions. This contributes to the UK's broader climate change targets and helps create a more sustainable energy future.
For the avoidance of doubt, this article is provided for informational purposes only and is not intended to constitute legal or financial advice. The author and/or Fuse Energy shall not be responsible for any losses arising out of any reliance on the information contained herein.
