Tongwei TNC 2.0 Efficiency Theory

How to Scientifically Evaluate

the Bifacial Power Generation Capacity of Modules?

Fan Hualong, Manager of the System Technology Department

of TW Solar Technology Center

answers questions on-site

Friends often wonder

Friends often wonder

what is the difference between

bifaciality and bifacial rated power?

Manager Fan explains that

the module nameplate power we usually see

only represents the front power generation capacity of the module

How to evaluate the power generation capacity of the back of the module?

The authoritative certification standard IEC 61215 has already provided the answer

where the bifacial nameplate irradiance (BNPI)

provides a standard for scientifically evaluating the power of bifacial modules

BNPI

which is the electrical performance of the module under a front irradiance of 1000W/㎡

and a back irradiance of 135w/㎡

(Other test conditions remain consistent with STC)

It reflects the comprehensive power generation capacity of bifacial modules

more than the STC rated power.

Bifaciality is one of the important factors

affecting the comprehensive power generation capacity of modules

Based on the G12R 66 version

conventional TOPCon modules are currently 620W

Tongwei TNC 2.0

has already achieved a 20W increase

in front power alone, i.e., 640W

Currently, the TOPCon modules on the market

have a bifaciality of 80%

The actual measurement result of Tongwei TNC 2.0 can reach 88%.

Calculating BNPI accordingly:

Conventional modules:

620W+620Wx80%x13.5%≈687W

Tongwei TNC 2.0 modules:

640W+640W*88%*13.5%≈716W

In outdoor conditions, Tongwei TNC 2.0

is a full 29W higher than conventional modules

135W/㎡ (irradiance), 13.5%

This is just a comprehensive state that IEC looks at

If the back radiation is particularly good in areas

such as desert areas

or the freezing areas in winter in Northeast China

the reflectivity is very high

IEC also stipulates BSI

with a maximum reflectivity of 30%

As for bifacial reliability irradiance (BSI)

this standard test conditions

use 1000W/㎡ irradiance on the front

but increase the back irradiance to 300W/㎡

(equivalent to 30% of front-side performance)

Other test conditions are also consistent with STC

simulating the extreme conditions of the back irradiance

that may be achieved in various application scenarios

Calculating BNPI accordingly:

Conventional modules:

620W+620Wx80%x30%≈769W

Tongwei TNC 2.0 modules:

640W+640W*88%*30%≈809W

It can be seen that

the higher the proportion of back irradiance

the more it can reflect the advantages of high bifaciality modules

resulting in higher comprehensive benefits of the modules

Tongwei TNC 2.0 modules

Tongwei TNC 2.0 modules incorporate the 908 technology (Tongwei's proprietary 0BB technology)

Stencil Printing Technology

Poly Tech Technology, and TPE Technology

resulting in higher power, higher bifaciality

and thus higher comprehensive benefits