The solar panel manufacturing process.
A solar panel is made by taking high-purity silicon (refined from sand), melting it into an ingot (a big block), then slicing it into wafers, thinner than a beer mat.
This wafer becomes the light-catching semiconductor at the heart of the cell, which is then 'doped' with boron or phosphorus to create the properties needed to turn sunlight into electricity (negative charge one side, positive charge the other side - which lets light knock electrons free to create power). The wafers are then coated with conductive layers, anti-reflective coatings and fine metal contacts.
This process forms a single cell, and to make the panel, multiple cells are connected with copper ribbons and laminated between a protective glass sheet on the front, to stop rain damaging the electrics, and a backsheet on the rear, using heat and pressure.
The finished laminate is then sealed into a frame, fitted with connectors and cables, before being tested, graded, and sent to installers ready for your roof.
- Panels are mostly glass, not silicon. By weight a typical crystalline panel is roughly 76% glass, 10% plastic polymer, 8% aluminium, 5% silicon and 1% copper, with a trace of silver.
- Most panels are made in China. Around 80% of finished modules and roughly 95% of the wafers and polysilicon inside them come from China. Very few panels are truly made in the UK.
- The energy used to build a panel is repaid fast. A UK system pays back its manufacturing energy in about 1 to 3 years, then generates cleanly for 25 years or more. That is separate from the 7 to 12 year financial payback.
What a solar panel is made of
Most people assume a solar panel is basically a slab of silicon. It is not. Silicon does the important job (turning light into electricity) but it makes up only about a twentieth of the panel by weight. The bulk of what you lift onto a roof is glass and aluminium.
| Component | Material | Job |
|---|---|---|
| Front cover ~76% | Tempered low-iron glass | Lets light through, shields the cells from hail, rain and debris |
| Encapsulant | EVA or POE polymer | Clear glue that seals the cells between the layers |
| Cells ~5% | Crystalline silicon | Convert sunlight into direct current electricity |
| Conductors | Silver paste and copper | Collect the current and carry it between cells |
| Backsheet | Polymer (or a second glass sheet) | Seals the rear and insulates it |
| Frame ~8% | Anodised aluminium | Adds rigidity and gives you something to clamp to the roof |
| Junction box | Polymer with bypass diodes | Routes the output and protects shaded cells |
How solar panels are made, step by step
The journey from a beach-coloured pile of sand to a working panel runs through seven broad stages, spread across several sites.
It starts with quartz, a form of silica (silicon dioxide) that is high-grade sand. The quartz is heated with carbon in an electric arc furnace at around 1,800°C. The carbon strips the oxygen away, leaving roughly 99% pure "metallurgical-grade" silicon. This stage is energy-hungry: producing one kilogram takes about 14 to 16 kWh, similar to running a domestic oven for seven hours.
99% pure sounds clean, but solar cells demand something closer to 99.9999%. The silicon is converted into a gas (trichlorosilane) using hydrochloric acid, then deposited back as ultra-pure "polysilicon" in the Siemens process. Only about 12% of the world's silicon output ends up pure enough for solar. This is the single most demanding step in the whole chain.
The polysilicon is melted and cast into a solid block called an ingot. For monocrystalline panels, a seed crystal is dipped into the molten silicon and pulled slowly upward so the whole block grows as one continuous crystal (the Czochralski method). For cheaper polycrystalline panels, the melt is simply cooled until many crystals form. A dopant such as boron or phosphorus is mixed in here to give the silicon its electrical charge.
A diamond wire saw cuts the ingot into wafers about 0.15mm thick, roughly the thickness of a couple of sheets of paper. The fine silicon dust lost in cutting is called kerf, and cutting that waste saves money and energy.
Each wafer is cleaned, textured and doped again so one side carries a negative charge and the other positive. That positive-negative boundary, the p-n junction, is what lets light knock electrons loose and create a current. An anti-reflective coating is added (this gives cells their blue or black colour) so they absorb light instead of bouncing it away, and fine silver and copper contacts are printed on to collect the electricity.
Cells are soldered into strings and laid onto the glass front, sandwiched in clear EVA encapsulant, then covered with a backsheet. The stack is heated and vacuum-laminated into one sealed, airtight unit. An aluminium frame is fitted for strength and a junction box with bypass diodes is bonded to the back to route the output.
Panels are checked throughout, but the final tests matter most. Electroluminescence imaging photographs the cells to catch hairline micro-cracks. A flash test then fires a burst of light equivalent to full sun (1,000 W/m² at 25°C) to measure exactly how much power the panel produces. Those Standard Test Condition figures end up on the spec sheet you compare when buying.
The shift to N-type: what has changed
Almost every "how are solar panels made" guide describes a boron-doped, p-type cell. That was accurate for a decade, but it is now out of date: the industry has moved to N-type cells, and it changes the last few steps.
For years the workhorse was PERC (Passivated Emitter and Rear Cell), a p-type design that held around 80% of the market as recently as 2022. PERC is doped with boron, which makes it prone to a small drop in output in its first weeks, and its efficiency is bumping against a ceiling of roughly 24%. The successor, TOPCon, is an N-type cell doped with phosphorus and given an ultra-thin tunnel oxide layer that cuts energy losses. It is largely free of that early degradation and reaches higher efficiencies.
TOPCon went from niche to the majority of new cell production in under three years:
| Technology | Type | Module efficiency | Status |
|---|---|---|---|
| PERC | p-type (boron) | 20.5-22.5% | Being phased out |
| TOPCon | n-type (phosphorus) | 22.5-23.5% | Now the volume standard |
| HJT | n-type hybrid | 23-24%+ | Premium tier |
Why should a UK buyer care? An N-type panel squeezes more output from the same roof and loses less over its life, which suits a British roof where space and light are limited. Many N-type panels now carry 25 to 30 year performance warranties as a result.
How other types of panel are made
The crystalline silicon process above covers about 95% of panels sold.
Thin-film panels
Instead of slicing wafers, thin-film panels are built by depositing an ultra-thin layer of light-absorbing material straight onto glass, metal or flexible plastic, then scribing it into cells with a laser. The common materials are cadmium telluride (CdTe), copper indium gallium selenide (CIGS) and amorphous silicon. It is cheaper and more flexible but less efficient, more common on commercial and utility projects than on homes.
Perovskite and tandem cells
Perovskite is a synthetic material that can be printed or coated on in liquid form, which is far simpler than growing silicon crystals. On its own it degrades quickly, so the near-term use is a perovskite layer laid over a normal silicon cell (a "tandem") to capture more of the light spectrum. This is the technology most likely to push panel efficiency past today's limits. The tandem approach was partly pioneered by UK-founded Oxford PV.
Where solar panels are made
Overwhelmingly China. Around 80% of the world's finished panels are assembled there, and it controls roughly 95% of global wafer and polysilicon production. Even a panel badged by a Western brand almost certainly contains Chinese wafers.
The biggest names by volume are Chinese: Jinko Solar, LONGi, Trina Solar, JA Solar and Tongwei make a large share of the world's modules. The main non-Chinese manufacturer of scale is First Solar in the United States, which makes cadmium telluride thin-film rather than silicon. That concentration makes supply chains a live political topic, and why "where was it made" is worth asking your installer.
Are any solar panels made in the UK?
Some, but fewer than the marketing suggests. Most panels installed in Britain are imported, and a lot of "British-made" branding means the panel was assembled or laminated here using cells shipped in from Asia. That distinction, module assembly versus where the cell was made, is what to pin down if buying British matters.
A handful of firms do manufacture here, mostly for specialist and building-integrated products rather than commodity panels.
| Company | Based | Known for |
|---|---|---|
| Solar Capture Technologies | Blyth, Northumberland | The largest genuine PV manufacturer in Britain; modules and integrated roof tiles |
| GB-Sol | Cardiff, South Wales | PV roof slates and bespoke building-integrated panels |
| Viridian Solar | Cambridgeshire | Roof-integrated panels that replace tiles for a flush finish |
| UKSOL | Buckinghamshire | British brand offering a 30-year warranty (cells sourced overseas) |
If you want the shortest possible supply chain, roof-integrated and BIPV products from these firms are the closest thing to a domestically made panel. For a standard rooftop array, you are almost certainly buying an imported module, and the imported Tier 1 panels that dominate the UK market are well made and heavily warrantied.
The energy and carbon cost of making a panel
Making a panel uses energy, most of it in that silicon purification step. The old sceptic's line is that a panel never generates as much energy as went into building it. That was true 40 years ago. It is false today.
Carbon tells the same story. A typical panel saves in the region of 900kg of CO2 a year once running, giving a carbon payback of around one to two years. Embodied-carbon figures have fallen so fast that many articles still quote numbers several times too high because they rely on decade-old data. That is a different question from the financial payback (typically 7 to 12 years in the UK), which is what it takes to repay the panel's cost to you in pounds.
Frequently asked questions
What raw material are solar panels made from?
Silicon, which comes from quartz sand (silica). It is the second most abundant element on Earth after oxygen.
Are solar panels made from rare or toxic materials?
Mostly no. The main ingredients (silicon, glass, aluminium) are abundant and safe. Silver is used in small amounts. The exception is cadmium telluride thin-film panels, which contain cadmium, but it is sealed inside the module and these are used mainly in large ground-mounted projects rather than on homes.
Can solar panels be recycled?
Yes. The glass and aluminium, which make up most of the weight, are readily recyclable, and processes to recover the silicon, silver and copper are improving. In the UK, solar panels fall under the WEEE (Waste Electrical and Electronic Equipment) regulations, so producers share responsibility for end-of-life collection and recycling.
What to remember when you buy
Almost every panel you will be quoted is imported, most likely from China, and only a handful of firms manufacture in Britain. The energy and carbon that built it are repaid within a few years, long before it stops working.
The detail that matters most is simpler than the manufacturing: is it a modern N-type panel from a reputable maker, and what payback does your roof deliver at today's prices?
METHODOLOGY: Verified against US Department of Energy manufacturing basics, the Union of Concerned Scientists and PVEducation. Cell-technology shares reflect 2026 industry reporting; composition by weight from the Institute for Sustainable Futures.
DISCLAIMER: This guide is for general information and is not financial advice. Efficiency, warranty and payback figures are indicative and vary by product, installer and location.
