Solar panels are now a familiar sight on rooftops across the UK — but most homeowners, even those seriously considering installation, aren’t entirely sure what’s happening inside them. Understanding how the technology works helps you make better decisions about system size, battery storage, and how to get the most from your investment. This guide explains everything clearly, without unnecessary jargon.
What Are Solar Panels and What Are They Made Of?
Solar panels — more accurately called photovoltaic (PV) panels — are made up of individual solar cells, each typically constructed from silicon. Silicon is a semiconductor material that reacts to light by releasing electrons. When multiple cells are connected and laminated behind a protective glass front, they form a solar panel. Multiple panels connected together form a solar array.
The two most common panel types are:
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Monocrystalline — Made from a single silicon crystal, these panels are more efficient and better in low-light conditions. They’re the most common choice for UK residential installations.
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Polycrystalline — Made from multiple silicon fragments, slightly less efficient but historically cheaper. Less commonly installed today as monocrystalline prices have fallen.
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Thin-film — Lightweight and flexible, but lower efficiency. Mostly used in commercial or specialist applications rather than domestic rooftops.
How Does a Solar Panel Generate Electricity?
The process is called the photovoltaic effect, discovered in 1839 by French physicist Edmond Becquerel. Here’s how it works step by step:
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Photons from sunlight hit the silicon cells and knock electrons loose from their atoms
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Those electrons flow through the cell in a single direction, creating a direct current (DC)
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DC electricity flows from the panels down to a solar inverter
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The inverter converts DC to AC (alternating current), which is the type of electricity your home appliances use
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AC electricity flows into your consumer unit (fuse box) and powers your home in real time
What Is a Solar Inverter and Why Does It Matter?
The inverter is the brain of your solar system. Without it, the electricity your panels generate can’t be used in your home. There are several inverter types:
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String inverter — One inverter connected to all panels in a series. Cost-effective and reliable, but performance can be dragged down if one panel is shaded.
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Microinverters — One small inverter per panel. More expensive but maximises output on roofs with partial shading or mixed orientations.
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Optimisers with string inverter — A middle-ground solution that adds panel-level monitoring and shading mitigation without the full cost of microinverters.
What Happens to Electricity You Don’t Use Immediately?
Surplus electricity that your home isn’t consuming in real time has two destinations:
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Exported to the grid via the Smart Export Guarantee, for which you receive a payment per unit
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Stored in a battery for use later — typically in the evening when solar generation has stopped but your consumption is at its highest
This is why battery storage transforms the economics of solar. Without a battery, most households export a large proportion of their generation at a relatively low rate. With a battery, they consume it themselves — at the full retail electricity price — dramatically increasing savings.
How Does a Battery Storage System Integrate With Solar?
A home battery connects to your inverter (or has its own hybrid inverter) and acts as a buffer between your solar generation and your home consumption. When your panels are generating more than you’re using, the surplus charges the battery. When your panels aren’t generating (evenings, overnight, cloudy periods), the battery discharges to power your home.
Compatible batteries for UK homes include the Tesla Powerwall, Fox ESS range, and Duracell Energy batteries — all of which HomeKog’s MCS-certified engineers install and commission as part of a fully integrated system.
Does a Solar System Work During a Power Cut?
Standard grid-tied solar systems automatically shut down during a power cut for safety reasons — to prevent electricity from feeding back into the grid while engineers work on it. However, certain battery systems — including the Tesla Powerwall — have a backup gateway that allows your home to island itself from the grid and continue running on solar and battery power during an outage. This is one of the most compelling reasons to add battery storage to a solar installation.
The Part Nobody Talks About: What Your Inverter Data Tells You
One of the most underused aspects of a solar installation is the monitoring data your inverter generates. Every modern inverter — and most battery systems — comes with an app or web portal that shows you real-time generation, consumption, export, import, and battery state of charge.
Homeowners who actively use this data typically save more money, because they learn to shift energy-intensive tasks (dishwasher, washing machine, EV charging) to periods when solar generation is high and battery is full. This behavioural shift doesn’t cost a penny but can add meaningfully to your annual savings — effectively turning your solar system into a daily energy management tool rather than a passive background technology.
Frequently Asked Questions
Q: Will solar panels damage my roof?
When installed correctly by MCS-certified engineers, solar panels should not damage your roof. Fixings are designed to seal around roof tiles and are waterproof. Panels can actually protect the roof section beneath them from weathering. It’s important to use a reputable, accredited installer and ensure any existing roof issues are addressed before installation.
Q: Do solar panels need maintenance?
Solar panels have no moving parts and require very little maintenance. An annual visual inspection and an occasional clean — particularly if you live in an area with heavy pollution, bird activity, or tree coverage — is generally sufficient. Your HomeKog engineer will advise on any specific maintenance considerations for your system at commissioning.
Q: Can I add battery storage to an existing solar system?
In most cases, yes. Many existing solar installations can be retrofitted with a battery storage system. The compatibility depends on your current inverter type — some older string inverters can be paired with AC-coupled batteries, while newer hybrid inverters integrate more directly. HomeKog can assess your existing system and recommend the best retrofit battery option.
