SunPower Tops in Mono C-Si Solar Cell Efficiency

The firm says it collated the numbers from public sources, including online product data sheets. All cells in this list are 156x156 in size.

SunPower's Maxeon mono c-Si cells came out on top with 22.5 percent efficiency. Just this week the company said it has put into commercial production new 24 percent-efficient Maxeon solar cells, to be integrated into "select" 128-cell panels that exceed 20 percent efficiencies, and which will be "available in limited quantities" later this year. The upgraded cells reportedly offer low reverse-bias breakdown voltage to improve performance in shady and dusty conditions, and better temperature coefficient to increase energy harvest in hot environments.

Panasonic (née Sanyo Electric), with its heterojunction with intrinsic thin layer (HIT) solar cells, ranks second in mono c-Si cell efficiency at 20.2 percent, just ahead of JA Solar at 20 percent, and Panasonic reportedly has its own 24 percent-efficient solar cells in the works. (We're also told by company reps that some Panasonic HIT panels have been rated at 20 percent efficient [or more] in the field for two years now.)

Solar cell suppliers ranked 4-11 all have cells that are 19-plus percent efficient, led by Suntech's 19.7 percent Pluto cells. (The company recently claimed it has devised a 20.3 percent efficiency [aperture area] "production cell.") After that are two dozen others with cells between 18-18.8 percent efficiency. The full list of 30 mono c-Si suppliers is here.

Note that cell efficiencies don't translate directly (and sometimes even indirectly) to module performance, once you build in all the other materials and components, supporting structures, etc. (Here is Solarplaza's top 10 mono c-Si module list from last summer.) Even a couple of percentage points in module efficiency can be important in determining system size required to achieve a given power yield. More importantly, though, raw efficiency numbers are only part of the solar PV system equation — one also needs to factor in module costs, cost per Watt-peak, cost per kilowatt-hour, and even the difference in real-life conditions in the field.

Top 10 most efficient solar PV monocrystalline cells. (Source: Solarplaza)