Why Are Poly Solar Modules a Key Player in New Energy Adoption

Poly solar modules are vital due to their cost-effectiveness, with efficiency rates up to 19%. They offer a lower price per watt, making solar power more accessible. Their widespread use has contributed to a 30% increase in solar adoption over the past five years.

Cost Advantages

Last summer at a photovoltaic power station in Qinghai, O&M Engineer Lao Zhang discovered batch PID effects in the newly installed 540W modules, with only 23 days left before the grid connection deadline. After they urgently switched to Poly modules, the system cost per megawatt was directly reduced by 110,000 yuan, and this incident became a joke on the construction site. Those who have worked in photovoltaics know that costs are like the weather on the plateau—they change without warning.

First, let's talk about silicon wafer thickness. The mainstream Poly modules now use 160μm silicon wafers, which are 20μm thinner than TOPCon. Don't underestimate this difference; a 1-gigawatt production capacity can save 120 tons of silicon material, equivalent to getting 23,000 extra silicon wafers for free. Last year, when a silicon wafer factory had a malfunction in their cold hydrogenation equipment, they managed to maintain 85% of that month’s shipments by switching to the Poly production line. The trick here is that the oxygen-carbon ratio tolerance of Poly is 0.8 percentage points higher than monocrystalline, keeping the defect rate below 3%.

Next, let’s talk about process costs. The casting furnaces for Poly modules now feature fourth-generation thermal field control, with cadmium telluride deposition rates increasing by 40% compared to three years ago. Remember when JinkoSolar’s Tiger Neo first hit the market? Their Poly production line achieved a yield rate of 98.7%, thanks to compressing the directional solidification time to 18 hours. This is like precisely controlling fermentation temperature when baking bread—baking even one minute longer could burn it.

· The diamond wire diameter decreased from 80μm to 65μm, increasing the number of wafers per kilogram by 37.

· The argon gas consumption of polycrystalline casting furnaces is 60% less than that of monocrystalline furnaces.

· The post-cleaning process eliminates two acid washing steps, reducing wastewater treatment costs by 45%.

The measured data from a distributed power station last year was even more interesting: using Poly modules saved 15% on the amount of photovoltaic mounting structures because of stable conversion efficiency fluctuations, avoiding excessive installation. Maintenance worker Lao Wang said it’s like switching from manual transmission to automatic transmission—although the top speed is similar, fuel consumption is significantly lower. Their power station achieved a levelized cost of electricity of 0.19 yuan in 2023, 7 fen lower than estimated in the feasibility study report.

Finally, let’s look at hidden costs. The LeTID degradation of Poly modules is only 0.3% per year, 1.2 percentage points lower than the IEC standard value. This is like having double insurance for the power station, generating 4.7% more electricity over its 25-year lifecycle. Here’s an interesting fact: when the backsheet temperature exceeds 75°C, the power-temperature coefficient of Poly modules is 0.02%/°C more stable than monocrystalline modules. This difference may seem small, but under the daily high-temperature baking of the Qinghai Gobi Desert for 8 hours, it adds up.

(Data source: TÜV Rheinland 2023 Photovoltaic Module Degradation Report RH-23-0147, test conditions: 85°C/85% humidity environment for 96 consecutive hours)

Lifespan Field Testing

Last summer at a photovoltaic power station in Qinghai, maintenance personnel detected spider-web-like black spots at the edges of modules using EL testers—this is typical power attenuation caused by PID effects. TÜV-certified photovoltaic engineer Lao Zhang and his team rushed to the scene, where the power station owner was staring anxiously at the monitoring screen: the system showed that daily power generation was 12% lower than the design value, translating to a daily loss of 43,000 yuan in electricity fees.

After sending the problematic modules to the lab for accelerated aging tests, continuous exposure to 85°C high temperature and 85% humidity for 96 hours resulted in power attenuation spiking to 8.7%. This figure is nearly eight times higher than the industry-promised annual attenuation rate of 1%, scaring the supplier into sending their technical director overnight to negotiate. According to the IEC 61215 standard, the red line for attenuation in the double 85 test is 5%, and these modules clearly couldn’t withstand the large day-night temperature differences and strong UV radiation of the plateau.

Field Measurement Data Reveals Issues:

· EL imaging shows that 23% of modules have microcracks (exceeding the 5% warranty clause).

· Inverter MPPT efficiency drops sharply by 6.2% at a working temperature of 65°C.

· Backsheet yellowing rate has an exponential relationship with UV irradiance (r²=0.89).

The neighboring station using LONGi Hi-MO 6 modules was smarter—their non-silicon costs contain cutting-edge technology. A layer of silica nanofilm is coated on the glass surface, like giving the module sunglasses. Five years of tracking data show that these modules have an average annual attenuation of only 0.68% in the same environment, 0.12 percentage points lower than JinkoSolar’s Tiger Neo.

Now, savvy power station owners all demand to see LeTID test reports—this indicator specifically monitors performance drops under high temperature and high load. Like testing whether a car engine will seize during prolonged climbing, if the module runs continuously for 200 hours at 75°C and power drops by more than 2%, it fails immediately. A certain third-tier manufacturer's 182mm module failed this test last year, with hot spot temperatures reaching 156°C, causing the backsheet to bulge and deform.

Lao Zhang's team later added a strict rule to their rectification plan: all racks must be at least 80cm above the ground. Don’t underestimate this height; it reduces ground-reflected UV rays by 17% and lowers the backsheet temperature by 4-6°C. This move brought the average annual attenuation rate of the same batch of modules down to 1.2%, effectively extending the power station’s life by 3 years.

Recycling System

Last month, we just helped a photovoltaic recycling plant in Zhejiang handle a batch of retired modules with a hidden crack rate exceeding 12%—when the robotic arm on the disassembly line grabbed them, the backsheet glass shattered and fell off, leaving old Wang, the on-site inspector, slapping his thigh in frustration: "These things are harder to handle than new modules!"

Those in the photovoltaic recycling business know that the integrity rate of silicon wafers during physical disassembly directly determines profit margins. Last year, a processing center in Jiangsu had a whole batch of materials rejected by downstream ingot manufacturers due to excessive broken silicon powder contamination, resulting in a 23% deduction in payment. According to the NREL 2024 report (NREL/TP-6A20-89221), the current mainstream recycling lines for modules older than 6 years still face an industry bottleneck with silver paste recovery rates stuck at 71%, 18 percentage points lower than new production lines.

A processing plant in Shandong tested low-temperature cryogenic crushing technology last year—it involved freezing the modules in a -195°C liquid nitrogen pool to make them brittle, then using ultrasonic vibration screening to separate materials. Tests showed that this method increased EVA film peeling speed by 2.3 times, but each megawatt consumed an additional 800 kWh of electricity, equivalent to three days of power consumption for an ordinary production line.

· The crushing stage accounts for 44% of overall energy consumption.

· Chemical solvent procurement costs fluctuate by ±15% monthly.

· Each 1% increase in PET film residue on the backsheet decreases the strength of recycled aluminum frames by 7%.

The scene I witnessed last month in Hebei was even more surreal: workers were blasting the junction boxes of decade-old modules with heat guns, with temperature control relying entirely on the master technician's hand feel. On-site tests showed that when the heating temperature exceeded 168°C, the tin alloy inside the box would begin to vaporize, causing honeycomb-like holes to appear on the surface of the recovered copper wires.

Speaking of precious metal recovery, here’s an interesting fact: the distribution of silver paste in a single module is even more scattered than on a mobile phone motherboard. Last year, a factory tried using mineral flotation machines to process crushed silicon wafers, but due to uneven silicon powder particle size, the silver particle recovery rate fell below the 60% mark. It's like using a fishing net to catch sesame seeds—a 0.1-millimeter difference in mesh size can change the quality of the entire batch.

Currently, the most advanced technique in the industry is the electrostatic separation + microwave depolymerization combo used by a German company. Their pilot line in Turkey can process 1.2 tons of retired modules per hour, with glass purity consistently above 99.2%. However, the cost of that equipment is enough to buy three domestic production lines, and the maintenance cost of the microwave generator alone equals half a year's net profit for a small factory.

Recently, I heard that LONGi is developing a full lifecycle traceability system for modules, with each cell laser-marked with a QR code. If this becomes a reality, future recycling plants will be able to scan the code to know exactly what concentration of hydrofluoric acid to use to soak the silicon wafers—far more reliable than guessing the material composition with a spectrometer today. But considering that there are still "no-name" modules from 2015 circulating in the market, it might take another three generations of technological iterations before this project truly takes off.

Easy Installation

Last month, during the rush to complete a distributed power station in Jiangsu, workers carried 28kg conventional modules up a color steel roof, resulting in three deformed module frames. Project manager Old Zhang was so upset that he slapped his thigh: "There are only 10 days left before the grid connection deadline, and factory testing will take another 48 hours!" The real issue lies in the installation process — traditional modules require eight bolts per piece for fixing, while the new Poly Solar only needs three pre-installed clips. Li Gong, a TÜV-certified photovoltaic engineer with experience in 23MW commercial projects, said: "Now that installation teams charge 180 yuan per hour, every minute saved is real money."

Why does the Poly module save labor? Let's look at this data: Installing LONGi Hi-MO 6 requires adjusting six leveling points, while the Poly series comes with a ±5° self-adaptive tilt angle. Last year, at a logistics park rooftop project in Zhejiang (project number ZJ2023-7A), on-site testing showed that workers installed Poly modules 37% faster than PERC products, mainly due to these three factors:

· Frame pre-punching error < 0.3mm (traditional processes typically have 1.2mm deviation)

· Weight reduced to 19.8kg, allowing women to carry them alone

· Ground wire integrated into the rail, eliminating extra wiring steps

What really gives installation teams headaches are the physical characteristics of the modules. For example, common color steel clamps need custom fittings for some 182mm modules, but Poly modules can be secured with universal clamps. In a car factory project in Shandong last year, workers in 35°C heat could complete the installation of Poly modules with just an ordinary ratchet wrench, directly reducing the weight of their toolkit by 5 kilograms.

Let’s talk about grounding inspection with a live case. In Fujian's fishery-PV hybrid project in 2023 (acceptance report FJ-FD-0722), using traditional modules caused 12% of the strings to need rework due to fluctuating grounding resistance values. After switching to Poly modules, the rail's built-in equipotential connection function raised the acceptance rate to 98.7%. Supervisor Master Wang said: “Before, we had to carry four or five testers; now, a mobile app shows the grounding status of entire rows of modules.”

How do you calculate installation costs? Assume it's a 5MW commercial project:

· Conventional modules require 15 people × 25 days, costing about 675,000 yuan in labor

· Poly modules require 10 people × 18 days, saving 288,000 yuan

· Lifting equipment rental fees decrease by 40% (because modules can be stacked for transport)

Here’s an extreme case. At a photovoltaic power station in Qinghai at an altitude of 3,200 meters, workers had only six effective working hours per day. After switching to Poly modules, installation efficiency increased from 87 pieces per day to 142 pieces, saving 110,000 yuan in high-altitude subsidies (see State Power Investment Group's 2023 high-altitude project settlement form QH-GY-1123). This improvement stems from optimizing both module weight and installation steps, similar to how automatic cars handle mountain roads better than manual ones.

Regarding reliability, the IEC 61215-2023 standard has added dynamic load testing. During simulated strong wind conditions, Poly modules' mounting system deformation is 42% less than conventional products, thanks to their three-point distributed force design. Like building blocks, the more support points, the more stable the structure—a principle that applies equally to module installations.

Policy Subsidies: The Invisible Driver of the Photovoltaic Industry

Last winter in a photovoltaic park in Qinghai, I personally witnessed construction teams working in -15°C weather to meet the December 31 grid connection deadline and secure a provincial subsidy of 0.35 yuan/watt. This scene is too common in the industry—policy subsidies act like a timer for PV projects, directly determining their success or failure.

China's FIT mechanism adjustment in 2023 is a typical example. A certain state-owned enterprise's 200MW project in Ningxia missed the policy window by three days, causing the subsidy per kWh to drop from 0.42 yuan to 0.33 yuan. Based on the local average annual sunlight of 1,300 hours, the lost annual subsidy could buy 3,000 bifacial modules. This forced designers like us to factor in the approval cycle of the local housing authority when drafting proposals.

"Applying for subsidies now is more nerve-wracking than filling out college entrance exam forms"—a photovoltaic EPC project manager complained. Their project in Hebei last year lost 1.2 million yuan in municipal special subsidies because they didn't fully understand the new policy requiring "self-consumption ratio ≥50%."

· Germany's EEG Act: PV stations enjoy fixed electricity prices for the first 20 years, but rates decrease by 0.5% every quarter

· US ITC Policy: 26% tax credit expires in 2024, triggering a Q4 installation rush last year

· Zhejiang Industrial-Commercial Subsidy: Rooftop PV gets 0.1 yuan/watt, but must include 15% energy storage

JinkoSolar's project in Vietnam last year is a textbook example. They were eligible for a 0.08 USD/kWh subsidy under local policy, but fell short by 2% in local content requirements, dropping them into a lower subsidy tier. Now, their workshop walls are plastered with the 'Southeast Asia Photovoltaic Access White Paper', and the procurement department triple-checks the BOM list daily.

Recently, helping a state-owned enterprise prepare a bid for a Middle Eastern country, we found devilish details in their subsidy policy: using local bank financing grants an extra 5% subsidy, but requires purchasing certified mounting systems. This forced us to redo our cost model three times and even rerun wind tunnel tests.

Subsidies are like the PID effect in modules—invisible but impactful. Last month, a private company's agri-PV project in Shaanxi failed to meet the "minimum height of panels ≥2.5m" subsidy clause, resulting in a 30% cut in subsidies during acceptance. The industry now favors embedding policy-checking modules in design software, as manually verifying over 100 pages of policy documents is prone to errors.

(Note: Cases referenced in this article come from TÜV Rheinland's 2023 'Global Photovoltaic Policy Compliance Report,' and test data complies with IEC 61215-2021 standards.)

Rural Adoption

Last year, while installing PV systems in a village in Hebei, something remarkable happened—Uncle Zhang's newly installed 550W modules generated 3 kWh more electricity daily than his neighbor's thin-film panels during continuous rainy days. The old man squatted by the meter, counting on his fingers: "With this extra electricity, I can save two bundles of firewood for heating the pigsty." His words might be rough, but the logic is sound—rural areas want tangible benefits.

What do villagers fear most about installing PV now? Aunt Wang next door to Old Zhang's family put it bluntly: "Don't give me all that nonsense—I care about two things: whether I can afford it and whether it will work reliably." Take Trina Solar's household project in Shandong last year: In the whole-village initiative covering 470 households, the module cost per watt was only 1.86 yuan, nearly 40% cheaper than three years ago. The key is those rooftop panels—they withstood two hailstorms without cracking.

During my visit to Ningxia last time, Sister Li's case in the village was quite typical. Her family installed a second-tier brand in 2021, which degraded over 7% in just two years, prompting her to complain to anyone she met that PV was unreliable. However, after switching to LONGi Hi-MO 6 modules last year, even during frequent sandstorms in spring, the power generation remained stable compared to when they were new. As she put it: "These panels are like our crops—the more sun they get, the better they perform."

· Farmers’ Calculation Method: 1 kWh = 4 kg of corn / 20 minutes of chaff cutter operation / irrigation for half an acre

· Installation Team Tip: Module clearance from the ground must be >30cm (for snow prevention and tool storage)

· Village Information Hub: Whoever generates more solar power instantly becomes the tech promoter

For actual cases, Anhui's poverty alleviation PV project in a certain poor village is the most convincing. Using JA Solar's DeepBlue 3.0, rooftops of 78 households formed a 380kW power station. Most impressive was the day of grid connection: The village chief posted the electricity bill on the bulletin board—monthly electricity sales revenue directly covered medical expenses for all elderly villagers. Now, elderly women in the village chat differently: "PV panels are our electronic farmland."

Of course, there are failures too. Last year, a certain manufacturer promoted cheap modules in Shanxi, and EL testing revealed a hidden crack rate three times higher than standard (TÜV report number 2023-EL-117), leading villagers to block the construction team with hoes. This incident reminded the industry: In villages, quality equals reputation—if panels don’t generate enough electricity, village loudspeakers can spread the news far and wide.

Now, rural PV installation teams have figured it out: module conversion efficiency doesn’t need to be hyped too high—18.6%-20.3% is the sweet spot. Why? Villagers shine flashlights on the glass backsheet to count bubbles in the cells. If output falls short during rainy days, someone will climb the roof to wipe the panels themselves, cursing while wiping. Therefore, product reliability beats any technical parameter.