What is the most expensive module of solar panels

Solar cells are the most expensive module, accounting for approximately 60% of the total cost.

The core cost lies in the refining and processing of high-purity monocrystalline silicon.

As the heart of photoelectric conversion, silicon price fluctuations and complex production processes directly determine the panel's selling price, making it the segment with the highest technical barrier.

Solar Cells

Cell Expenses

Currently, P-type cells, which hold the mainstream market position, and N-type cells, which are undergoing rapid iteration, dominate the final price of PV panels through their raw material costs, processing efficiency, and equipment depreciation.

Taking a monocrystalline cell with a size of 182 mm by 182 mm (M10 specification) as an example, its peak power usually ranges between 7.5W and 8.2W.

The material expenditure plus processing fees for producing such a cell account for 62% to 68% of the total budget for the entire PV module.

In this segment, the unit price of silicon wafers after high-purity polysilicon has been pulled into rods and sliced consumes about 75% of the total cell expenditure.

The remaining 25% is allocated to silver paste printing, acid washing processes, vacuum coating, and subsequent testing stages.

The Money in Silicon Wafers

The first step in producing monocrystalline silicon wafers is to place electronic-grade polysilicon with a purity of "9 Nines" (99.9999999%) into a monocrystalline furnace for rod pulling at temperatures above 1400 degrees Celsius.

The mainstream slicing thickness in the industry has now been compressed from 170 microns in the past to 130 microns or even 110 microns.

The primary purpose of this thinning process is to cut more effective wafers from each kilogram of silicon material, thereby reducing the cost per watt.

Based on current industry averages, 1 kg of silicon material can yield approximately 60 to 65 wafers of the 182 mm specification.

If the price of silicon material fluctuates at 60 RMB per kg, the raw material cost allocated to each wafer is approximately between 0.9 RMB and 1 RMB.

In addition to the material itself, diamond wire consumables used in the slicing process are a fixed expenditure.

Current diamond wire diameters have reached as thin as 34 to 36 microns, with consumable costs for every 10,000 wafers being approximately 150 to 200 RMB.

This extremely thin steel wire loses about 30% of the silicon material during high-speed operation, forming "silicon powder." 

Are Processing Fees High?

Turning a blank silicon wafer into a cell capable of generating current requires complex chemical and physical changes.

On the production line, non-silicon processing costs per watt (excluding the wafer and silver paste) are usually maintained between 0.14 RMB and 0.18 RMB.

Of this amount, about 40% is paid for factory electricity, as diffusion furnaces and Plasma Enhanced Chemical Vapor Deposition (PECVD) equipment require 24-hour high-power operation.

Another 25% goes to equipment depreciation. An Atomic Layer Deposition (ALD) machine costing tens of millions of RMB is typically depreciated over 5 to 7 years.

Specialized pastes must be applied to the front and back of the cell using screen printing technology. The most expensive is the front-side silver paste, with prices fluctuating above 7000 RMB per kg.

To improve photoelectric conversion efficiency by 0.5%, manufacturers often adopt a higher ratio of fine grid line designs, which increases printing frequency.

If the silver paste consumption for a single cell is controlled between 80 mg and 100 mg, this material alone adds about 0.6 RMB to the cost per cell.

Efficiency Technology Account

The current market is undergoing a comprehensive transition from legacy technologies to new ones (such as TOPCon or HJT).

Although the initial investment per watt for new technology is 20% to 30% higher than for legacy technology, its conversion efficiency can be raised from 23% to over 25.5%.

With the same installation area and the same frame and glass expenditures, the output power of a whole module can increase by 20W to 30W.

This improvement in efficiency directly impacts the end-user's ROI.

If a power station has a service life of 30 years, every 1% increase in conversion efficiency can result in approximately 1200 kWh of additional cumulative power generation per kilowatt of installed capacity under the same sunshine conditions.

Calculated at an electricity price of 0.4 RMB, this 1% technical premium can create an additional 480 RMB in revenue over the life cycle.

Therefore, even if new technology cells have a factory premium of 0.05 RMB to 0.08 RMB higher per watt, the market is still willing to pay for it.

Yield Rate Calculation

On the cell production line, the breakage rate, micro-crack rate, and the rate of substandard electrical performance after each process directly determine the factory's break-even point.

The comprehensive yield rate of top-tier factories is usually maintained between 97% and 98.5%.

If the yield rate drops by 1%, the comprehensive amortization cost per watt rises by 0.015 RMB.

To ensure that the power degradation rate over 25 years does not exceed 20%, the cell surface is covered with a passivation film tens of nanometers thick (such as aluminum oxide or silicon nitride).

The uniformity error of these coatings must be controlled within 5%.

If the passivation effect is poor, Light-Induced Degradation (LID) and Potential-Induced Degradation (PID) of the cell will increase significantly, leading to a power drop of more than 10% after 3 to 5 years of installation.

The hidden expenditure for this risk control is actually included in the approximately 0.1 RMB R&D and quality inspection cost for each cell.

Other Major Modules

The material in aluminum frames

The outermost aluminum alloy frame of a PV module typically uses the 6063-T5 model. The amount of aluminum used for each 580W module fluctuates between 2.4 kg and 2.9 kg.

Thickness specifications for aluminum frames are mostly 30 mm or 35 mm, with wall thickness precision maintained between 1.1 mm and 1.5 mm.

Based on the current market price of aluminum ingots at 18,000 to 21,000 RMB per ton, the frame cost for a single module is approximately 45 to 60 RMB.

Regarding structural strength, these aluminum frames must ensure that the physical deformation remains below 1% after the module undergoes tests of 2400 Pa wind pressure and 5400 Pa snow pressure.

Because the aluminum surface undergoes 12 to 15 microns of anodic oxidation treatment, it ensures continuous operation for 25 years in environments with 85% humidity and 85 degrees Celsius without large-scale corrosion.

In the Bill of Materials (BOM) of a complete PV panel, the cost of the aluminum frame consistently accounts for 10% to 13%. Its processing fee per ton is usually 2,500 to 3,500 RMB higher than the raw aluminum ingot, depending on the complexity of the cross-section design and punching accuracy requirements.

Tempered Glass Panels

Current mainstream single-sided modules use 3.2 mm thick ultra-white patterned tempered glass, while bifacial modules more commonly use a 2.0 mm + 2.0 mm double-glass structure.

The iron content of this glass is strictly controlled below 150 ppm to ensure that light transmittance in the 380 nm to 1100 nm band remains stable between 91.5% and 93.5%.

For 3.2 mm thick glass, the weight per square meter is approximately 8 kg. For a module with an area of 2.5 square meters, the glass alone weighs 20 kg, accounting for more than 66% of the total weight (approx. 30 kg).

In terms of market quotes, the procurement unit price for the 3.2 mm specification is between 24 and 28 RMB per square meter, while the 2.0 mm specification, due to higher yield requirements, usually costs between 18 and 22 RMB per square meter.

The thickness of the Anti-Reflective Coating (ARC) on the glass surface is only 100 nm to 150 nm, but this thin film can reduce light reflectivity from 8% to about 2%, thereby bringing an additional 8W to 12W of power gain for a 550W module.

Encapsulation Films

The encapsulation films sandwiched between the cells, glass, and backsheet mainly consist of EVA and POE, with weight distribution ranging from 450 g to 600 g per square meter.

A standard bifacial module requires approximately 2.2 square meters of film, with a budget expenditure between 18 and 25 RMB.

EVA film light transmittance is usually required to be greater than 90.5%, and its Vinyl Acetate (VA) content is locked at a specific ratio of 28% to 33% to ensure peel strength remains above 60 N/cm under extreme temperature differences from -40 to 85 degrees Celsius.

POE film prices are 20% to 40% higher than EVA, but its water vapor transmission rate is only 0.5 g/m²/day, which is more than 90% lower than ordinary EVA, effectively preventing PID in N-type cells over a 30-year lifespan.

The film undergoes a lamination process at 145 to 155 degrees Celsius in a heating furnace. The degree of cross-linking must reach the 75% to 85% range; otherwise, after 3 to 5 years of field installation, the film may shrink or yellow by more than 5%, leading to a sharp drop in power generation efficiency.

Rear Protection Box (Junction Box)

The junction box installed on the back of the module usually possesses an IP68 protection rating and integrates 3 bypass diodes to handle the 20% to 50% power shading loss caused by partial shadows.

The rated current of the junction box is usually between 15A and 25A, capable of withstanding DC system voltages of 1000V or 1500V.

A complete junction box set includes two dedicated PV cables with a length of 1,200 mm and a cross-section of 4 mm², with procurement costs controlled at 16 to 22 RMB.

The tinned copper core resistance of the cable must be lower than 5.09 ohms per km and must be able to run continuously for 20,000 hours at 120 degrees Celsius without the insulation skin cracking.

The heat dissipation efficiency inside the junction box directly affects diode life. High-performance junction boxes at a 15A full-load current usually have their internal temperature rise limited to within 30 degrees Celsius, which can reduce the system failure rate by 0.05% to 0.1%.

Back Insulation Layer (Backsheet)

For single-sided modules, the backsheet provides the final insulation protection, with a total thickness typically between 300 and 350 microns.

The backsheet is a composite of a Polyvinylidene Fluoride (PVDF) or Polyvinyl Fluoride (Tedlar) outer layer, a Polyester (PET) middle layer, and a Polyethylene (PE) inner layer. This three-layer structure provides a breakdown voltage strength of over 15,000 V.

Currently, KPE or TPT structure backsheets cost 10 to 15 RMB per square meter, accounting for 3% to 5% of the total cost.

Its water vapor transmission rate specification is required to be below 2.5 g/m²/day. After 2000 hours of UV and damp-heat aging tests, the growth of its Yellowness Index (YI) must be controlled within 3.0.

If the backsheet's reflectivity to sunlight is increased from 70% to 85%, it can add about 1% to 2% current gain to the front of the module through secondary reflection in the gaps between cells. This premium can bring millions in extra power generation revenue for power station projects above 1 GW.

How to Choose

Check Conversion Efficiency

When selecting modules, a conversion efficiency between 21% and 23.5% is the primary indicator for distinguishing product tiers.

Taking a standard-sized module of 2 square meters as an example, a panel with 20% efficiency has a power of about 400W, while a 23% efficiency panel can reach 460W.

For the same 100 square meter installation area, high-efficiency modules can provide 3 kW more in total installed capacity.

Mass-produced N-type TOPCon cells generally operate at 24.5% to 25.5% efficiency, which is an absolute value about 1.5% to 2.0% higher than traditional P-type PERC cells.

This efficiency difference directly shortens the investment recovery cycle by 8% to 12% because higher power output reduces the cost per kilowatt of brackets, cables, and labor by approximately 0.15 to 0.25 RMB.

· Single module dimensions are usually 2,278 mm by 1,134 mm, with a total area of about 2.58 square meters.

· Power density fluctuates between 210 W and 230 W per square meter, depending on cell arrangement gaps.

· Every 1% increase in selected conversion efficiency can create 1500 to 2000 kWh of additional electricity revenue in 30 years of cumulative power generation.

· In environments where the roof load limit is 15 kg/m², high-efficiency modules can reduce the bracket structural load pressure by 10%.

· System voltages usually run at 1000V or 1500V. High-efficiency panels can reduce the number of series circuits by about 5%.

Calculate Power Degradation

All solar panels experience an initial Light-Induced Degradation (LID) of 1% to 2% in the first year after installation, followed by a linear degradation phase of 0.4% to 0.55% per year.

For P-type modules, the remaining power after 25 years is usually guaranteed to be above 84.8% of the initial value. For N-type modules, which have stronger anti-degradation performance, the remaining power after 30 years can still be maintained at around 87.4% to 89%.

In the last 10 years of the life cycle, the power generation revenue per kilowatt of N-type modules will be about 3% to 5% higher than that of P-type.

When calculating the Levelized Cost of Energy (LCOE), this 0.1% annual degradation rate difference must be factored into the formula, as it corresponds to a net profit difference of about 800 RMB over 30 years.

Parameter Item	P-type PERC Module Index	N-type TOPCon Module Index	Gain/Loss Deviation
First-year Power Degradation	Approx. 2.0%	Within 1.0%	1.0% power gain
Avg. Annual Linear Degradation	0.55% per year	0.40% per year	0.15% annual generation diff.
30-year Power Retention	Near 83.1%	87.4% to 89.3%	Approx. 5% end-stage diff.
Low-light Generation Gain	95% of nominal value	98% of nominal value	3% gain on rainy days
Premium per Watt	0.00 RMB Baseline	0.05 to 0.12 RMB	5% to 10% increase in budget

Check durability

The physical strength of the module is determined by the 3.2 mm tempered glass and the 6063-model aluminum alloy frame.

It must pass 5400 Pa forward static load testing (simulating heavy snow) and 2400 Pa back-side static load testing (simulating strong wind).

In hail-prone areas, it is necessary to confirm that the module can withstand the impact of hail with a diameter of 25 mm at a speed of 23 m/s without micro-cracks exceeding 0.1%.

The IP68 protection level of the junction box means it can be immersed in 1.5 meters of water for 30 minutes without leaking electricity.

The junction temperature of the internal diodes must be controlled below 150 degrees Celsius to prevent cell temperatures from exceeding the safety limit of 85 degrees Celsius when hot spots occur due to partial shading.

· Anodic oxidation film thickness for aluminum frames should reach 12 to 15 microns to handle 25-year salt spray corrosion risks.

· The water vapor transmission rate of the backsheet must be lower than 2.0 g/m²/day to prevent internal circuit oxidation from increasing resistance by more than 5%.

· Laminate peel strength should be above 60 N/cm to ensure no delamination occurs in extreme cold environments of -40 degrees Celsius.

· The temperature coefficient is a key indicator, usually ranging from -0.29%/°C to -0.35%/°C. A smaller value means less power drop in high-temperature environments.

· When summer roof temperatures reach 75 degrees Celsius, modules with a temperature coefficient of -0.3% can output 2% more real-time power than those with -0.35%.

Monitor Warranty Periods

Standard market warranties are divided into 12 to 15 years for product workmanship and 25 to 30 years for linear power output.

Workmanship warranties cover manufacturing defects such as frame cracking, junction box detachment, or backsheet bubbling. The probability of such issues is typically controlled within 0.05%.

The power warranty is a guarantee of generation capacity. If the module power falls below 80% of the initial value in the 20th year, the manufacturer must bear 100% responsibility for replacement or cash compensation.

When purchasing, it is necessary to verify the manufacturer's financial stability indicators over the past 10 years, as a 30-year warranty relies on a corporate credit that can survive for more than 30 years.

· The 12-year product warranty covers about 95% of the potential manufacturing failure cycles.

· Power linear compensation typically drops at a slope of 0.5% per year rather than in steps.

· In the claim process, measurement errors for power deviation are usually allowed within a 3% laboratory tolerance range.

· If the guaranteed generation at the 25th year is 85%, it cumulatively produces about 35,000 kWh per kilowatt.

· Additional policies provided by third-party insurance companies (such as Munich Re) provide 100% credit backing for warranties.

Compare Cost-Effectiveness

Facing procurement unit prices of 0.9 to 1.2 RMB per watt, simply pursuing the lowest price can lead to an increase in the Levelized Cost of Energy (LCOE) of more than 15% over 25 years.

For a small 10 kW system, selecting modules that are 0.1 RMB cheaper but 2% less efficient saves 1000 RMB in initial investment, but the total power generation over 25 years will decrease by about 12,000 kWh. At an electricity price of 0.5 RMB, the loss is as high as 6000 RMB.

Therefore, a reasonable purchasing logic is to compare LCOE, which is the total system investment divided by the estimated total power generation over 25 years.

If the calculated cost per kWh is more than 50% lower than the local electricity price, the module solution is highly economically feasible.

· Balance of System (BOS) costs such as brackets and cables account for about 25% to 30% of the total investment.

· Labor installation costs are typically calculated at 0.2 to 0.4 RMB per watt. High-power modules can reduce labor time consumption by 10%.

· Maintenance costs run at 0.5% to 1% of the annual total investment, including panel cleaning once per quarter.

· The DC/AC ratio for inverters is usually set between 1.1 and 1.3 to maximize the utilization of the PV panel's over-generation capacity.

· In regions with 1,300 hours of solar resources, the annual power generation revenue per kilowatt fluctuates between 600 and 800 RMB.