In this article we offer a broad overview of the types of panel that are available, the materials they are made of, explain what some of the data on the manufacturer specification sheets means and ask some questions, the answers to which will hopefully make your choice a bit easier. The article assumes that you already have figures in mind (kWh) that you would like to generate from your PV system. If you are a homeowner and need help to work this out, we have an appliance energy usage form that you may find useful here.
What are Solar PV Panels Made of?
The primary material needed to make a Solar PV panel is silicon, how the silicon is engineered and treated gives rise to three different types of Solar Photovoltaic Panel, with different prices, uses and levels of performance.
- Monocrystalline PV Panels:
A Monocrystalline panel consists of a number of solar cells connected together to form a grid. Monocrystalline Solar cells are made using thin wafers of silicon cut from a single crystal. Silicon wafers are expensive to produce but are very efficient conductors. When comparing panels a Monocrystalline panel is likely to be the most expensive and the most efficient panel in terms of energy generation per sqm.
- Polycrystalline PV Panels:
A Polycrystalline panel is made in much the same way as the Monocrystalline panels mentioned above except the wafer is cut from a block of silicon crystal made up of many crystals. A Polycrystalline Panel will be slightly less efficient and slightly cheaper to buy then Monocrystalline.
- Amorphous Cells:
A Solar PV panel made from Amorphous cells need not neccessarily be built into a panel at all. We sometimes use Amorphous Cells in roofing materials, you can see some of the solutions where we use Amorphous silicon here. They are less expensive to produce but their efficiency is a lot lower then their crystalline counterparts. Amorphous cells are made by spreading a thin film of silicon onto a material, amorphous cells have the added benifit of being flexible.
Peak Power (kWp):
With Solar Panels the maximum output power is measured in watts, generally speaking the larger the panel the more solar cells you can fit into it. An important point that needs to be understood is that UK installations very rarely if ever perform at peak performance.
Mounting Area:
If you got the chance to use the Solar PV Calculator above you will see that factors such as height above sea level, the tilt inclination of the panels and the location of the installation relative to the equator all have an impact on a panels performance.
You now need to specify what panels are most suitable based on the mounting area you need to work with. You could be limited by factors such as chimneys, shading, skylights or dormer windows. This factor along with your power requirements may well determine the size number, type and style of the panels you need to get.
Planning Permission:
Planning regulations have recently been relaxed when it comes to household renewable energy installations but are still an area to give some thought to especially if you are a planning a large installation or in a conservation area. It may be worth having a quick look at our Building Integrated Solar section to see what can be done when traditional panels aren’t an option or will affect the looks of a building.
Guarantees and Warranties:
A Solar PV system is likely to be a big investment, if an individual panel doesn’t pay for itself within the guarantee period and fails soon after the warranty expires, then financially the investment just wont make sense. In our exprience the guarantees supplied by the manufacturers can be relied upon as a good indication as the likely lifetime of the panel. It’s often worth paying a little extra for a longer warranty.
About The Author
Glen Freeman is a renewable energy systems designer and co-owner of In Balance Energy Ltd. In Balance are specialist designers, suppliers and installers of bespoke energy systems for homeowners, businesses and communities in the UK.
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