Monocrystalline vs Polycrystalline Solar Panels

Monocrystalline solar panels now outsell polycrystalline solar panels by a substantial margin according to data published in 2019 by the Department of Energy funded Lawrence Berkely Labs.

Most of the top 20 models of residential solar panels in 2020 are monocrystalline. The reason for this is that monocrystalline solar panels are more efficient and due to new technology, they are being made cheaper – and sold for cheaper – making them the same price as many Tier 1 polycrystalline panes.

However, in our view, the price premium charged by Sunpower, LG, and Panasonic for their monocrystalline panels is not justified by their additional performance, and homeowners should look to other high-quality monocrystalline brands such as Canadian Solar, Trina Solar, Jinko Solar, JA Solar, and Longi.

It was once the case that polycrystalline solar panels were 20-30% cheaper than monocrystalline solar panels because producing monocrystalline cells was a more expensive process than producing polycrystalline cells. However, now, many cell manufacturers have converted their furnaces over to make monocrystalline cells rather than polycrystalline cells, making the cost similar.

In our opinion, this does not reflect any underlying defect in polycrystalline panels that should steer a consumer away from polycrystalline solar panels, so long as they are offered at a good price from a reputable Tier 1 manufacturer.

It is also worth noting that new solar cell technologies are being developed that could challenge both monocrystalline and polycrystalline solar panels in the not-too-distant future.

The Key Facts About Each Type of Solar Cell

Monocrystalline Solar Panels

Overview and Appearance 

This is the oldest and most developed of the three technologies. Monocrystalline panels, as the name suggests, are created from a single continuous crystal structure. A monocrystalline panel can be identified by the solar cells, which all appear as a single, flat color.

Construction

Monocrystalline solar panels are made through the Czochralski method, where a silicon crystal ‘seed’ is placed in a vat of molten silicon. The seed is then slowly drawn up with the molten silicon forming a solid crystal structure around the seed, called an ‘ingot’. The ingot of solid crystal silicon that is formed is then finely sliced into what is known as a silicon wafer. This is then made into a cell.

The Czochralski process results in large cylindrical ingots. Four sides are cut out of the ingots to make silicon wafers. A significant amount of the original silicon ends up as waste.

Polycrystalline Solar Panels

Overview and Appearance 

Polycrystalline, also known multicrystalline, is a newer technology and its manufacturing process can vary.

Construction 

Polycrystalline panels also start as a silicon crystal ‘seed’ placed in a vat of molten silicon. However, rather than drawing the silicon crystal seed up as with monocrystalline, the vat of silicon is allowed to cool. It is the cooling that forms the distinctive edges and grains within the solar cell.

Between 2012 and 2016, polycrystalline cells were thought to be inferior to monocrystalline cells because they were slightly less efficient. However, because of the cheaper method by which they were produced, coupled with only slightly lower efficiencies, they enjoyed a significant market share in residential installations.

Polycrystalline cells, with continued quality improvements, have helped push the standard 60-cell polycrystalline panels from 240W to 300W over the last five years.

Polycrystalline cells are now very close to monocrystalline cells in terms of efficiency.