Solar Panels – Choose Your Technology!

If you are looking for a solar power system, the major part of that system is going to be “solar PV (photovoltaic) panels” (which I’ll just refer to as “solar panels” from here on) that convert sunlight into electricity using a phenomenon called the photovoltaic effect.

There are 3 major types of solar PV technology.

1. Monocrystalline
3. Thin Film

Only the first two technologies – monocrystalline and polycrystalline – are available in Australia these days. Thin film is no longer used here for residential installations.

The following are some details on each type of technology, including thin film just for general interest purposes:

1. Monocrystalline Solar Panels

Some think of monocrystalline solar panels as the ‘Rolls Royce’ of solar PV technology and the best choice. Monocrystalline is one of the oldest technologies, and more expensive to make, but this type have the highest efficiency.

These panels can typically achieve 15-20% conversion efficiency in the real world, i.e. convert 16-21% of the sunlight that hits them into electricity. They are made from wine-bottle sized single crystals of ultra-pure silicon and sliced up like salami to make individual wafers.

These circular wafers have their sides cut square, and are then converted into a monocrystalline “solar cell” that looks like this:

A Monocrystalline Solar Cell

The silver lines are wires that collect the electricity that is created when light hits the cell. The solar panel is made up of a matrix of these moncrystalline solar cells laid flat – like tiles on your bathroom floor:

monocrystalline solar PV panel

Monocrystalline solar cells are generally high performance, but because they waste a bit of space between the cells when they are encapsulated in a solar PV panel (the little white diamonds in the picture above) they perform about the same (in efficiency and power terms) as polycrystalline.

The easy way to spot mono solar panels on a roof is to look for the tell tale white diamonds between the cells.

(Top tip for keeping the kids busy in the car: Play “spot the solar panel” with bonus points for identifying the technology type! Yes I really do make my long-suffering kids play that game…)

monocrystalline solar pv array

2. Polycrystalline Solar Panels (Also Called Multicrystalline)

Polycrystalline solar panels are also made from silicon, but the type of silicon used is slightly less pure and they are cast into blocks rather than sawn from a single crystal. The fact that the crystals are randomly arranged means that they are visible individually.

Once the polycrystalline ingot is cast, it is sawn into square blocks and then sliced into square wafers that are processed to convert them into solar cells.

Here’s a close up of a polycrystalline solar cell – you can see that it looks very different to the sleek, uniform appearance of its monocrystalline rival:

Polycrystalline Solar Cell

Polycrystalline solar cells are very similar to monocrystalline in performance and degradation, except in multicrystalline, the resulting cells are typically slightly less efficient. However, as you can see here, there is no wasted space between the corners of the perfectly square cells:

Polycrystalline Solar pv Panel

This means that when they are encapsulated in solar PV panels, there is slightly more area available to absorb sunlight. The result is that a polycrystalline solar panel’s performance is almost identical to monocrystalline solar panels. Here’s what they’ll look like on your roof:

polycrystalline solar pv array

3. Thin Film Solar Panels

Whereas mono and polycrystalline solar panels are made in very similar ways, thin film solar panels use a completely different method of manufacturing. Instead of creating solar cells by sawing up large blocks of silicon, a film containing silicon is “sprayed” on to the surface that is to become a solar panel.

As mentioned above, thin film panels are basically obsolete in Australia, due to mono and poly panels far outstripping them in price and performance – I haven’t seen them sold here for many years!

So to sum up, which solar panels are best type in terms of technology?

When choosing between monocrystalline vs polycrystalline solar panels, despite what many salespeople will tell you, there is nothing really to distinguish between the types – except their looks!

Thin-film was slightly cheaper per kW, but occupied at least twice the area, and no-one is 100% sure how much they will degrade in the long term. However, as mentioned thin film panels are no longer available for the Australian residential solar market – so this technology choice is one you won’t have to make.

>>Next: How to compare panel brands >>

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