Gridly
Polycrystalline Silicon
An older solar cell technology made from multiple silicon crystals. Lower efficiency (15–18%) and a speckled blue appearance. Largely superseded by monocrystalline in new Australian residential installations.
What polycrystalline is
Polycrystalline (also called multicrystalline) silicon panels are made by melting silicon and pouring it into moulds, where it cools and solidifies as multiple crystals rather than a single continuous one. The result is a cell with visible grain boundaries - multiple crystal domains with different orientations - which impede electron flow compared to a single crystal.
The manufacturing process is simpler and cheaper than growing a single-crystal boule for monocrystalline production. That cost advantage made polycrystalline panels the dominant technology from the 1990s through the mid-2010s.
Why you rarely see it in new installations
Efficiency improvements in monocrystalline manufacturing - particularly the PERC process - closed the price gap substantially. By the late 2010s, monocrystalline panels had become comparable in price per watt while delivering meaningfully higher efficiency (20–22% vs 15–18%).
The consequence: polycrystalline is now largely uncompetitive for new residential installations in Australia. Paying a similar price per panel for lower efficiency doesn’t make sense when the monocrystalline alternative fits more watts into the same roof space.
When you’ll still encounter it
Polycrystalline panels appear in:
- Older existing systems (pre-2018 installations). If you’re buying a home with an existing solar system, it may well have polycrystalline panels. They perform adequately - the efficiency is lower, but the panels themselves are durable and will continue generating for years.
- Low-cost imports at the budget end of the market. Some still use poly cells, though even cheap Chinese manufacturers have largely shifted to monocrystalline.
Performance comparison
In real-world Australian conditions, polycrystalline panels generate less per square metre. A 72-cell polycrystalline panel from 2015 might be rated at 300W in 1.95 m². The equivalent monocrystalline panel today in the same area might be 420–440W. For a homeowner with a fixed roof area, the difference is significant.
If you have an old polycrystalline system, replacement with modern monocrystalline panels on the same mounting hardware can increase generation by 30–45% without changing the system footprint.