Explainer: How do you make solar panels?

Over the past decade, China has grown to dominate the global solar panel manufacturing industry. The country has invested over $50 billion in new solar PV capacity since 2011 - 10 times more than Europe, according to the International Energy Agency (IEA). And it has created 300,000 new manufacturing jobs in the industry.

As manufacturing capacity has increasingly moved from Europe, Japan and the United States, China’s share of all the manufacturing stages of solar panels has grown, and now tops 80%. In addition to this, the country is also home to the world’s 10 top suppliers of solar PV manufacturing equipment.

The country has been instrumental in lowering the prices of solar panels worldwide. But at the same time, having such a concentration of capacity in one geographical area creates potential challenges for supply chains and needs to be addressed by governments, the IEA says.

A solar panel is made up of many cells, each formed from multiple layers of a semi-conducting material. Silicon is by far the most commonly used semiconductor. It is the main component of sand, making it widely available, but converting it to high-quality silicon is costly and energy intensive. Polysilicon prices have surged in recent years, reaching their highest point since 2011 in July 2022.

Crystalline silicon is melted and mixed together with boron to give it a positive electrical polarity. The silicon is then shaped into cylindrical ingots.

The ingots are then cut into paper-thin slices known as wafers. These wafers are then coated with an anti-reflective coating to prevent the naturally shiny surfaces from reflecting back the sun’s rays.

Wafers are placed back-to-back and heated in the presence of phosphorus to create solar cells. The phosphorus creates a negative electrical polarity.

Electrical contacts, made of an incredibly thin substance so as not to block the sun, are placed to connect the cells to one another.

The cells are connected together to form a solar panel by encapsulating them in silicon rubber or ethylene vinyl acetate. The panels are then mounted in an aluminium frame that has a mylar or tedlar backsheet and a glass or plastic cover.