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GCL Brand review

NT10/78GDF-640W

640 Wp TOPCon Bifacial 80%
ComparePV verdict

Solid all-round for its segment

Rank 2,095 of 14,129
Compare panels Datasheet PDF
Power (Wp)
640
Strong · top 9%
Efficiency (%)
22.90
Typical · median 22.80%
Density (Wp/m²)
229.0
Typical · median 227.7
Temp (%/°C)
-0.290
Typical · median -0.290
Weight (kg)
33.6
Typical · median 32.8 kg
Warranty (yrs)
30
Typical · median 30 yrs

The GCL NT10/78GDF series introduces a new quality to large-scale energy installations thanks to the use of advanced N-type TOPCon technology. Replacing traditional solutions with N-type cells allows for a significant reduction in LID and LeTID light degradation, directly addressing the issue of performance decline in the initial years of system operation. Through the use of an innovative bifacial dual glass structure, these panels effectively utilize light reflected from the ground, generating noticeably more energy even at a low solar angle. These modules are primarily dedicated to professional investors building solar farms and large commercial facilities, where maximizing yield from limited land or roof space is key. Exceptional resistance to extreme mechanical loads and an excellent temperature coefficient ensure this series outperforms standard products in terms of operational stability during summer heat. The use of a larger cell format results in a real reduction in BOS installation costs, which significantly shortens the payback period for the entire investment. By choosing this model, the investor gains the assurance of maximum system longevity and effective protection against micro-cracks, guaranteeing stable power production and failure-free operation for many decades.

Ranking

1,085 panels in the segment TOPCon 600-650 W
Metric This panel Median Position in segment Overall rank
Module efficiency 22.90% 22.80% Typical 2,412
Power density 229.0 227.7 Typical 2,443
Temperature coefficient -0.290 -0.290 Typical 2,220
Weight per kWp 52.5 53.1 Typical 6,090
Performance warranty 30 yrs 30 yrs Typical 21
Colour key Strong - top 25% Typical - middle 50% Weak - bottom 25%

Signals from the data

5 positive · 2 caution
Best for

Utility-scale, commercial and hot-climate.

What owners get
Low Temperature Coefficient of Pmax

N-type TOPCon technology delivers a Pmax temperature coefficient of -0.29%/°C (GCL NT10/78GDF datasheet), which is notably superior to typical PERC panels that reach -0.34-0.35%/°C. For a 1 MWp installation in the Polish climate, this translates to a realistically higher summer energy yield of approximately 1-2% per year compared to older technologies.

30-Year Power Warranty at ≥87.4%

GCL guarantees a minimum of 87.4% of nominal power output after 30 years of operation, exceeding the industry-standard threshold of 84.8% commonly applied in the sector. For a 5 MWp PV plant, this difference translates to several additional MWh per year in the final years of operation, materially improving project IRR.

Bifacial Dual Glass - Confirmed Rear-Side Gain

The dual glass construction with N-type bifacial cells enables rear-side energy yield of up to 25-30% relative to the front side (per manufacturer data and IEC TS 60904-1-2), which in ground-mounted installations over high-albedo surfaces (gravel, concrete, snow) significantly increases annual energy production with no increase in material costs.

Mechanical Load Rating of 3,600/1,600 Pa

The allowable load of 3,600 Pa on the front side and 1,600 Pa on the rear side (GCL NT10/78GDF datasheet, ManualsLib) places this module among the top-rated for mechanical resistance in the >630 Wp segment, qualifying it for installation in climatic zones with heavy snowfall (zones III-IV per PN-EN 1991-1-3) without the need for a denser racking structure.

BNEF Tier 1 Manufacturer - Bankability Confirmed

GCL System Integration appears on the BNEF Tier 1 solar module list for Q1 2026 (BNEF Tier 1 Solar Module Methodology, March 2026) and is ranked #2 globally by annual module shipment capacity. Bankable status is a key requirement for non-recourse project financing of PV plants and streamlines lender due diligence.

Trade-offs
Max. Efficiency 23.43% vs. Segment Leader at 24.2%

The Tongwei TWMNH-66HD (a direct peer comparable at the same 655 Wp power class) achieves 24.2% efficiency-0.77 percentage points higher than the maximum value of the GCL NT10/78GDF (23.43%). For projects with constrained roof or land area, such as an industrial rooftop, this means approximately 3.4% more GCL modules would be required to achieve the same installed capacity.

Product Warranty of Only 12 Years

The product warranty is 12 years, whereas several premium manufacturers in this segment-including Jinko Tiger Neo and LONGi Hi-MO 7-offer 15-year product warranties. For projects financed by institutions that require a product warranty of ≥15 years as a condition of insurance or financing, this may necessitate additional coverage in the form of performance bonds or warranty insurance policies.

Notes from the database
  • Efficiency of 22.9% matches the TOPCon 600-650W median
  • Power density of 228.9 W/m² matches the TOPCon 600-650W median
  • At -0.29%/°C, hot weather performance is typical for TOPCon 600-650W panels
  • Bifacial design (80% factor) captures reflected light - adds 4-12% yield on ground-mount or white roof
  • In the top 17% for efficiency among all TOPCon panels

Specifications

Open datasheet PDF
Nominal power (Pmax) 640 Wp Nameplate at 1000 W/m², 25 °C
Module efficiency 22.90 % Typical Segment median 22.80%
Vmpp · Impp 48.68 V · 13.15 A Operating point at max power
Voc · Isc 57.15 V · 13.90 A Sizes the string length
Max system voltage 1500 V Longer strings than 1000 V modules
Dimensions 2465×1134×30 mm · 2.80 m² of roof
Weight 33.6 kg Typical Typical · median 32.8 kg
Cells 156 · TOPCon Monocrystalline
Bifaciality 80 % Rear output as a share of front
Coefficient Pmax -0.290 %/°C Typical median -0.290 of its segment
Coefficient Voc · Isc -0.250 · 0.045 %/°C
Product warranty 12 years Hardware defects only
Performance warranty 30 years Typical median 30 yrs · median 30 yrs
End-of-warranty output 87.4 % Equals 559 W guaranteed
Degradation 1.00 → 0.40 % First year, then annual

Datasheet charts

Open datasheet PDF

Measured curves published by GCL in this model's datasheet. A chart carrying a wattage was measured on that variant alone - only the ones that describe 640 Wp appear here. The rest cover the whole series.

Linear Performance Warranty Linear Performance Warranty Whole series

Simulations

Live - change any input
Lifetime output & value
30 years at 1200 kWh/kWp/year and €0.50 per kWh
Power in year 30
-
Lifetime energy
-
Energy value
-
With bifacial gain
-

Degradation from this panel's own datasheet figures. No inverter, soiling or shading losses.

Heat losses
-0.290 %/°C against a segment median of -0.290
-
Bifacial gain
Rear gain over light concrete: -
-

Model: bifaciality × albedo × 0.6 view factor. A first-order estimate, not a yield simulation.

Filter these
Size
Panel Power Eff. Temp. Weight Difference
GCL NT10/78GDF-640W 640 W 22.90% -0.290 33.6 kg You are here
AIKO-A650-MAE72Mw 650 W 25.20% -0.260 27.0 kg Cooler, lighter, +2.3 pp
AIKO-A680-MDE72Mw 680 W 25.20% -0.260 29.0 kg +40 W, lighter, +2.3 pp
AIKO-A675-MDE72Mw 675 W 25.00% -0.260 29.0 kg +35 W, lighter, +2.1 pp
AIKO-A645-MAE72Mw 645 W 25.00% -0.260 27.0 kg Cooler, lighter, +2.1 pp
WST-675BKX72-A2 675 W 25.00% -0.260 32.1 kg +35 W, cooler, +2.1 pp
AIKO-G670-MCH72Mw 670 W 24.80% -0.260 28.2 kg +30 W, lighter, +1.9 pp
LR7-72HVHF-670M 670 W 24.80% -0.260 28.5 kg +30 W, lighter, +1.9 pp
GCL-NT10/78GDF-630 630 W 22.54% -0.290 33.6 kg -10 W, -0.4 pp
GCL-NT10/78GDF-635 635 W 22.72% -0.290 33.6 kg Very close match
GCL-NT10/78GDF-645 645 W 23.07% -0.290 33.6 kg Very close match
GCL-NT10/78GDF-650 650 W 23.25% -0.290 33.6 kg +10 W, +0.4 pp
AIKO-A700-MAE78Dw 700 W 25.00% -0.260 34.5 kg +60 W, cooler, +2.1 pp
AIKO-A695-MAE78Dw 695 W 24.90% -0.260 34.5 kg +55 W, cooler, +2.0 pp
JKM650-670N-66QL6-BDV (670W class) 670 W 24.80% -0.260 32.5 kg +30 W, cooler, +1.9 pp

Found 616 panels of the same or similar size to this one, within ±10 mm. See them here Found 616 panels of the same or similar size to this one, within ±25 mm. See them here Found 616 panels of the same or similar size to this one, within ±50 mm. See them here Found 1838 panels of the same or similar size to this one, within ±100 mm. See them here

About the NT10/78GDF series

6 answered

These answers cover the whole series. Where a figure differs, the specification above is this module's own.

What warranty covers the GCL NT10/78GDF series panels and what does it include?
The GCL NT10/78GDF series comes with a 12-year product warranty against manufacturing defects and a 30-year linear power output warranty. In practical terms, after the first year the module will retain at least 99% of its nominal power, and after 30 years of operation it will still produce a minimum of 87.4% of the declared rated power. This places the NT10/78GDF among the best-warranted utility-scale modules currently available on the market.
Does the TOPCon technology in the GCL NT10/78GDF series offer a real advantage over standard PERC panels?
Yes, the difference is tangible. The N-type TOPCon cells used in the NT10/78GDF series exhibit significantly lower LID and LeTID degradation rates compared to P-type PERC cells. This translates into a smaller power loss during the first months of operation and a higher energy yield over the entire system lifetime. The power temperature coefficient is only -0.29%/°C, providing a real performance edge during summer heat compared to typical PERC modules rated at -0.35%/°C.
How does the bifacial design of the GCL NT10/78GDF panels work, and when does it make sense to choose it?
The bifacial dual-glass construction allows the module to capture solar irradiance from both the front glass and the rear glass, which collects diffuse and ground-reflected radiation. The rear-side gain depends on the albedo of the surface beneath the array. The greatest benefits are achieved in ground-mounted systems over bright soil, gravel, or snow, as well as on flat rooftops with light-colored membranes. Under favorable conditions, the additional energy yield from the rear side can reach several to more than ten percent.
Are the 655 W GCL NT10/78GDF panels suitable for a commercial rooftop installation on an industrial building?
Yes, the NT10/78GDF series is specifically designed for large commercial and industrial installations. The module's dimensions of 2465 × 1134 × 30 mm and a weight of approximately 33.6 kg require a properly engineered mounting structure; however, its certified mechanical resistance to wind and snow loads (up to 3,600 Pa front-side and 1,600 Pa rear-side) ensures safe operation even in demanding climatic conditions. The large-format cell design also reduces balance-of-system (BoS) costs per installed kilowatt.
How does the GCL NT10/78GDF series perform at high temperatures during summer?
With a power temperature coefficient of -0.29%/°C, the NT10/78GDF series loses less efficiency during heat waves than the majority of PERC-based modules. For example, at a module surface temperature of 65°C the power loss amounts to approximately 10.4%, whereas a typical PERC panel would lose more than 12% under the same conditions. Across an entire photovoltaic power plant, this difference translates into a measurable additional energy yield during the hottest months of the year.
Is GCL, as the manufacturer of the NT10/78GDF panels, a reliable partner and can the warranty obligations realistically be fulfilled?
GCL System Integration (GCLSI) is classified as a Tier 1 manufacturer by BloombergNEF, confirming its financial stability and demonstrated ability to honor long-term warranty commitments. The company is one of the world's largest producers of photovoltaic wafers and modules, with a sustained presence in European and global markets. For investors developing utility-scale PV farms, this classification is a key consideration when selecting a module supplier and assessing long-term project bankability.
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