Solar Electric Panel Types

Image: Salvatore Vuono /

Photovoltaic Panels

Photovoltaic panels use silicon to covert solar energy into electric but not all panels are the same. This article identifies some of the main panel types.

Panel Types

Mono-crystalline Silicon Cells:
Made using cells saw-cut from a single cylindrical crystal of silicon, this is the most efficient of the photovoltaic (PV) technologies. Mono-crystalline cells have high efficiencies, typically around 15%, although the manufacturing process required to produce mono-crystalline silicon is complicated, resulting in slightly higher costs than other technologies.

Poly-crystalline Silicon Cells (multi-crystalline):
Made from cells cut from an ingot of melted and recrystallised silicon. In the manufacturing process, molten silicon is cast into ingots of polycrystalline silicon; these ingots are then saw-cut into very thin wafers and assembled into complete cells. Poly-crystalline cells are cheaper to produce than mono-crystalline ones.

Thick-film Silicon:
Another multi-crystalline technology where the silicon is deposited in a continuous process onto a base material giving a fine grained, sparkling appearance. Like all crystalline PV, this is encapsulated in a transparent insulating polymer with a tempered glass cover and usually bound into a strong aluminium frame.

Amorphous Silicon (thin film):
Amorphous silicon cells are composed of silicon atoms in a thin homogenous layer rather than a crystal structure. Amorphous silicon absorbs light more effectively than crystalline silicon, so the cells can be thinner. For this reason, amorphous silicon is also known as a "thin film" PV technology. Typical efficiencies of around 6%, but they are easier and therefore cheaper to produce.

Electricity Generation

Photovoltaic electricity generation can be calculated from the following formula from the SBEM Technical Manual available from BRE

  QPV = I • KE • (1-KS) • A


 QPVthe annual electricity produced by the photovoltaic modules (kWh)
 I: the global solar radiation at the module surface (kWh/m2)
 KEthe module efficiency of conversion (%)- see table 1
 KSthe system losses (%)- see table 2
 A: area of the photovoltaic module excluding the supporting construction (m2)
 Table 1: Conversion Efficiency  Table 2: System Losses
 Mono-crystalline15%  Inverter losses7.5%
 Poly-crystalline12%  Module shading2.5%
 Amorphous6%  Module temperature3.5%
 Other thin films8%  Shading2%
    Mismatch and DC losses3.5%
    MPP mismatch error1.5%
    AC losses3%
    Total Losses25%

Data from the SBEM Technical Manual available from BRE

Other Examples

Also see the Carbon Trust article solar electricity photovoltaics  This link opens a new window

Photovoltaic Panels - last updated 30th January, 2014 by Corny