Your guide to harnessing the power of the sun: Understanding Solar Panels

Have you every wondered how solar panels work? Or whether they truly deliver on their promise? Many are sceptical, but the truth is, these incredible devices are revolutionising home energy. Our Solar Expert, Thomas Lavery, demystifies solar panels.

The UK's solar landscape is rapidly changing. As of March 2025, over 1.5 million homes across the UK are powered by solar panels, with 150,000 of those in Scotland alone. This surge in popularity might surprise some, as it's common to wonder just how effective solar technology can be under our famously cloudy skies. Many are sceptical, believing our weather simply isn't sunny enough. But before we address those doubts, let's first explore the fundamental science behind how these panels work.

What Exactly Are Solar Panels?

At their core, solar panels (also known as photovoltaic or PV panels) are devices designed to convert sunlight directly into electricity. Think of them as miniature power plants that sit on your roof, quietly transforming the sun's rays into usable energy for your home.

The secret to solar panels' energy-generating ability lies in their construction. Most solar panels are made up of several layers, with the star of the show being the photovoltaic cells. These cells are typically made from silicon, a semiconductor material, and do the work of converting sunlight into electricity.

Other important layers in the design include a top layer of tempered glass to protect the delicate cells from the elements, and an encapsulant layer, often made of EVA (ethylene vinyl acetate), that encases the silicon cells, providing further protection and bonding them together.

Additionally, there will be a backsheet, which is a durable, weather-resistant layer on the back that protects the internal components and provides electrical insulation, and an aluminium frame to surround the entire panel and provide structural integrity and make them easy to mount.

How Do Solar Panels Create Energy from the Sun? The Photovoltaic Effect

The magic behind solar panels is a process called the photovoltaic effect. Don't let the name intimidate you - it's quite straightforward and incredibly clever. It all begins when sunlight hits the silicon atoms within the PV cells. Tiny packets of energy called photons strike these atoms, giving their electrons a burst of energy and making them jump out of their usual positions. Once freed, these electrons get moving, flowing in a specific direction to create an electric current.

At this stage, the electricity generated is Direct Current (DC), just like what you'd find in a battery. However, your home appliances run on Alternating Current (AC). This is where a clever device called an inverter comes in: it takes the DC electricity from the panels and converts it into usable AC electricity, ready to power everything in your home.

But Do They Actually Work in the UK? Addressing the Scepticism

It's common for people, especially in the UK with its reputation for cloudy skies, to be sceptical about solar panels' effectiveness. The good news is, yes, solar panels absolutely work in the UK. Here's why:

Light, Not Just Direct Sun: Solar panels generate electricity from daylight, not just direct sunlight or heat. While they produce more power on bright, sunny days, they can still generate significant electricity on overcast or cloudy days by capturing diffused light.

Winter Performance: While energy output is lower in winter due to shorter daylight hours, solar panels still function. In fact, cooler temperatures can even enhance their efficiency, as extreme heat can reduce performance. Even light snow typically slides off angled panels or melts, and a thin layer of snow won't completely block light.

Grid Connection: Almost all domestic solar panel systems in the UK remain connected to the national grid. This means your home will automatically draw power from the grid when your solar panels aren't generating enough (e.g., at night or during heavy cloud cover), ensuring a continuous electricity supply. Any surplus energy you generate can be exported back to the grid, earning you money through schemes like the Smart Export Guarantee (SEG).

How Are Solar Panels Installed on a Property?

Installing solar panels is a job best left to qualified professionals, as it ensures both safety and the system's optimal performance. The process typically begins with a thorough site assessment. An installer will carefully evaluate your roof, taking into account its size, angle, potential shading from nearby trees or buildings, and overall structural integrity to make sure it can safely support the panels and the necessary drilling.

Once the assessment is complete, scaffolding is often erected to provide safe access for the installation team. Next, a robust mounting system is securely attached to your roof's rafters, creating a stable base for the panels. The solar panels themselves are then carefully lifted onto the roof and securely bolted to this racking system.

Following this, the electrical wiring begins. The individual panels are wired together, and cables are run from the panels to the inverter, which is usually situated in your loft, garage, or a utility room. The inverter is then connected to your home's main electrical consumer unit (fuse box), integrating the solar power directly into your home's electrical system.

Finally, once all components are in place, the entire system undergoes commissioning, where it's thoroughly tested and switched on, ready to start generating clean, renewable energy for your home.

Are They Worth Buying? Cost, Carbon Emission Savings, and the Payback Period

This is a crucial question for many homeowners. While solar panels represent an upfront investment, their long-term benefits are substantial, making them a worthwhile purchase for most households in the UK.

Reduced Electricity Bills: By generating your own electricity, you significantly reduce your reliance on expensive grid power, leading to noticeable savings on your monthly energy bills. The amount you save depends on your energy consumption, the size of your system, and local electricity prices.

Potential for Export Tariffs: The Smart Export Guarantee (SEG) scheme allows you to get paid for any surplus electricity you generate but don't use, and export back to the grid. This can add a significant income stream, with an average home potentially earning up to £500 per year.

Increased Property Value: Homes with solar panels are often seen as more attractive to buyers due to lower running costs and environmental benefits, potentially increasing their resale value.

Significant Carbon Emission Savings: This is where solar truly shines for the environment. By using clean, renewable energy from the sun, you drastically reduce your household's carbon footprint. An average solar panel system can cut a household's carbon footprint by over 1 tonne of CO2 per year, contributing significantly to combating climate change.

The Payback Period: When Do They Pay for Themselves?

The payback period is the time it takes for the savings on your electricity bills and any export tariff earnings to equal the initial cost of your solar panel system. This is a key factor for many considering solar.

In the UK, the average payback period for a domestic solar panel system (typically 4-5kW, suitable for a 2-3 bedroom house) is currently estimated to be around 8 to 12 years. Some sources suggest as low as 5 years for optimal setups, while others range up to 13 years, particularly for smaller systems or those without batteries.

Given that most solar panels come with performance guarantees of 25 years or more, the payback period typically falls well within the system's lifespan, leaving you with many years of free, clean electricity and ongoing savings.

The Power of Storage: Understanding Solar Batteries

While solar panels are fantastic at generating electricity during the day, what happens when the sun goes down or on particularly cloudy days? That's where solar batteries come in.

A solar battery allows you to store the excess electricity your panels generate during peak sunlight hours. Instead of sending this surplus back to the grid immediately (though you can still do that if you wish), it's stored in the battery for later use. This means you can increase self-sufficiency, maximise your solar investment and provide backup power.

While adding a solar battery increases the upfront cost, the enhanced self-consumption and potential for greater savings can often justify the investment, with typical battery payback periods estimated between 5-12 years.

Solar panels are a powerful and increasingly accessible technology that empowers homeowners to take control of their energy consumption, save money, and contribute to a greener future. Despite historical doubts, their proven performance in the UK, coupled with significant financial and environmental benefits, makes them an increasingly smart choice for modern homes.