How Can Polycrystalline Photovoltaic Panels Help Reduce Solar Costs

Polycrystalline panel technology is mature, with costs 10-20% lower than monocrystalline.

Although efficiency is about 15-17%, the low silicon consumption and low unit price make it a cost-effective solution for large-scale installations, significantly shortening the investment payback period.

Manufacturing Efficiency

Fast furnace output 

The single charging amount of polycrystalline silicon casting furnaces currently generally reaches 800 kg to 1200 kg, which is an increase of more than 2 times compared to the 300 kg to 400 kg single load of monocrystalline pulling furnaces.

The entire melting, directional solidification, and cooling cycle is precisely controlled between 42 hours and 58 hours, and the monthly production capacity of a single casting device is stable at 12 tons to 15 tons of silicon ingots.

Since the casting process does not require complex seeding and necking operations like monocrystalline, the labor hours for a single operation are shortened by about 35%.

In a melting point environment of 1414 degrees Celsius, the formation speed of polycrystalline silicon ingots is maintained at 10 mm to 20 mm per hour. This batch production mode dilutes the equipment depreciation cost per kilogram of silicon ingot to 3 to 5 Yuan RMB.

The polycrystalline production line has a higher tolerance for raw material purity and can use secondary silicon materials or recycled materials with a purity of 6 nines (99.9999%), which are 15% to 20% cheaper than the 9 nines pure materials dedicated to monocrystalline.

In a production plan of the 1000-ton level, choosing polycrystalline raw materials can save about 12 million to 18 million Yuan in the procurement budget.

The service life of the quartz crucible during the casting process reaches more than 50 hours, and the cost of consumables for a single use is about 4000 Yuan, making the cost allocated to each watt of the module less than 0.01 Yuan.

This large-scale, low-threshold manufacturing model allows the factory to complete the ramp-up process from equipment installation to full production within 3 months.

Lower electricity costs 

The electricity consumption per kilogram in the polycrystalline silicon manufacturing stage is maintained at 45 to 55 kWh, which saves about 30% in power expenses compared to the 65 to 80 kWh of the monocrystalline pulling process.

In a panel factory with an annual output of 5GW, electricity expenses account for 12% to 15% of the total operating costs. Adopting the polycrystalline process can save about 45 million kWh per year.

The heating power during the directional solidification process is stable at 60 kW to 90 kW, and the power consumption during the cooling stage drops rapidly to below 10 kW.

This energy conversion efficiency makes the carbon footprint per watt of polycrystalline modules 10% to 12% lower than similar products, meeting the carbon emission assessment standards for green energy products in more than 80% of countries worldwide.

The temperature control system in the production workshop keeps the ambient temperature constant at 22 to 26 degrees Celsius, and the humidity is maintained within the range of 30% to 45%. The energy consumption index per square meter of factory building is 0.5 kWh per hour.

Polycrystalline silicon ingots do not need to undergo multiple high-temperature annealing treatments like monocrystalline before cutting, saving about 12 hours of heat treatment procedures.

This simplification of the process flow keeps the factory's transformer load rate in the economic operating range of 70%, reducing reactive power loss fees by 5%.

In areas where the industrial electricity price is 0.6 Yuan per kWh, the electricity cost advantage of a single polycrystalline silicon wafer is maintained between 0.12 Yuan and 0.18 Yuan.

Less silicon wafer waste 

Using diamond wires with a diameter of 0.08 mm to 0.1 mm for slicing, the wafer yield of polycrystalline square ingots is as high as 60 to 65 wafers per meter.

The consumable loss rate (kerf loss) during the cutting process is controlled within 0.06 mm, which saves 25% of silicon material compared to the early slurry cutting process.

The thickness of 156.75 mm specification polycrystalline silicon wafers has been thinned from 200 microns to 180 microns, and the weight of each wafer has been reduced by about 0.5 grams.

This reduction in weight can reduce the load by 50 kg in a shipment of 100,000 wafers, thereby reducing long-distance logistics costs by 3%.

Automated slicing machines can handle 1,200 to 1,500 wafers per hour, and the breakage rate is strictly limited to an extremely low level of 0.2% to 0.3%.

The wire consumption per wafer for diamond wire is controlled within 0.08 Yuan RMB, with a consumption of about 1.2 meters to 1.5 meters per wafer.

The recycling rate of cutting fluid reaches more than 95%, and the wastewater discharge per 10,000 wafers is reduced by 1.5 tons.

The depth of the texturing pits on the surface of polycrystalline silicon wafers is controlled at 3 to 5 microns.

This microstructure can improve the reaction efficiency of the solution by 2% in the subsequent diffusion process, further reducing chemical costs by 0.02 Yuan.

More durable equipment 

The mean time between failures (MTBF) of polycrystalline casting furnaces exceeds 5,000 hours, and the annual maintenance downtime is less than 150 hours.

Compared to complex monocrystalline furnaces, the number of wearing parts in polycrystalline equipment is reduced by 40%, and the annual spare parts procurement cost is reduced by 50,000 to 80,000 Yuan.

The floor space of a single device is only 12 to 15 square meters, allowing 20% more capacity equipment to be arranged in the same factory area.

The output rate per unit area of the factory reaches 250 kW to 300 kW per square meter per year, and the land use efficiency is improved by about 15%.

Automated robotic arms on the production line complete a picking action every 3 seconds, with a repetitive positioning accuracy of 0.05 mm, ensuring a 99.5% packaging yield.

The cycle time of the vacuum laminator is set at 12 minutes to 15 minutes, and it can process 4 to 6 standard 72-cell modules at a time.

The lamination temperature is controlled at around 145 degrees Celsius, with an error of no more than plus or minus 2 degrees Celsius, ensuring a cross-linking degree of over 90% for the EVA film.

This equipment stability allows the factory to maintain a comprehensive equipment efficiency (OEE) of over 90% in a 24-hour continuous operation mode.

Stable cell shipment

The average photoelectric conversion efficiency of polycrystalline cell cells stabilized at 18.5% to 18.8% in 2024, with the positive and negative deviation of mass production batches controlled within 0.1%.

In the screen printing process, the single-sheet usage of silver paste is precise to 80 mg to 100 mg. By adopting 5BB or 9BB technology, silver paste costs are reduced by 8% to 10%.

The pull strength test data for cell cells is stable at 2.5 Newtons or more, ensuring that no busbar breakage occurs in the 25-year outdoor vibration environment.

The electroluminescence (EL) inspection pass rate of single-sheet cell cells reaches more than 98%, and the proportion of black chips and broken busbars is lower than 0.5%.

The power binning step for finished modules under Standard Test Conditions (STC) is 5 watts, and more than 90% of products are concentrated in the mainstream brackets of 330 watts to 345 watts.

Packaging boxes use a 30 pieces/box specification, and the loading capacity of a single container (40-foot high cube) reaches 720 to 840 modules.

The module frames use 30 mm to 35 mm 6063-T5 aluminum alloy, with the cost of aluminum material per meter being about 15 to 20 Yuan, which can resist a wind load of 2400 Pascals.

These highly standardized production and logistics parameters ensure that the total loss rate of polycrystalline modules from the factory to the installation site is lower than 0.1%, locking in 100% of the arrival power revenue for investors.

Economies of Scale Benefits

Save big on material procurement 

In the photovoltaic manufacturing supply chain, when the factory's annual production capacity increases from 500 MW to 5 GW, the raw material procurement bargaining power usually brings a direct cost reduction of 12% to 18%.

Procuring more than 1000 tons of polycrystalline silicon material, the unit price is often 8 to 15 Yuan RMB per kilogram lower than small orders of the 50-ton level.

For 3.2 mm thick tempered photovoltaic glass, annual procurement contracts at the 10-million square meter level can drive down the unit price by about 10%, saving about 2.5 to 3.5 Yuan per square meter.

The 6063 aluminum profiles required for photovoltaic frames will see processing fees charged by suppliers drop from 6000 Yuan to 4500 Yuan per ton at a 10,000-ton order volume.

This bulk procurement mode allows the BOM (Bill of Materials) cost of polycrystalline modules to drop by 0.05 Yuan to 0.08 Yuan/watt in the overall budget.

Scale procurement makes the material cost of projects over 100 MW 15.5% lower than that of 1 MW distributed projects. Through centralized commissioning on a 10GW production line, silver paste consumption can be reduced by 3.2%, increasing the premium space per watt by more than 2%.

Chemical consumables required for polycrystalline cell production, such as hydrofluoric acid and nitric acid, are transported by tankers instead of drums in large-scale continuous production, reducing logistics and packaging costs by more than 20%.

If the procurement specifications for backplanes and EVA films are unified to standard sizes of 156.75 mm or 166 mm and the order volume exceeds 500,000 square meters, manufacturers usually give a cash rebate of 5% to 8%.

Large-scale production can also reduce the unit packaging carton cost from 0.015 Yuan per watt to 0.009 Yuan, and the pallet recycling rate can also be improved from 60% to 92%.

This all-round material saving allows factories with an annual output of more than 2 GW to have an additional gross margin buffer of more than 5% during market fluctuations.

Continuous production line 

The comprehensive equipment efficiency (OEE) of large polycrystalline manufacturing plants is usually maintained between 94% and 96%, while small factories often have an OEE of only about 80% due to frequent changes in product specifications.

In a 24-hour continuous operation mode, the annual depreciation cost of a single casting furnace is diluted through 8,500 hours of operation time, and the fixed asset cost allocated per watt of the module is only 0.03 Yuan to 0.04 Yuan.

Since the production process is highly standardized, the average rework rate per 10,000 cells is controlled within 0.15%, which is 0.5 percentage points lower than the sporadic production mode.

Automated inspection equipment on the production line handles 3600 cells per hour, with the average labor cost per inspection point being less than 0.001 Yuan RMB.

24-hour full-load operation reduces electricity expenditure per watt by 0.012 Yuan.

The equipment early warning maintenance system reduces unplanned downtime by 18%.

The annual output value per unit area of the factory reaches 45,000 Yuan to 62,000 Yuan RMB.

Inside a 5GW-level factory, the number of devices managed by a maintenance engineer is 2.5 times that of small factories, meaning the labor cost per watt has been reduced by about 40%.

The cooling water circulation system for polycrystalline silicon ingots reaches 15 to 20 reuse cycles under large-scale operation, with water consumption per watt controlled below 0.8 liters.

After allocating the maintenance costs for workshop purification levels in large-scale production lines, it only takes 12 to 18 yuan per square meter per month, saving 30% of the environmental O&M budget compared to low-capacity workshops.

This efficient capacity utilization has brought forward the static investment payback period of the project by about 6 to 9 months.

Diluted freight costs 

When using 40-foot high cube (40HQ) containers for global transportation, the single-container load reaches 720 to 800 polycrystalline modules, and the freight per watt can be suppressed to 0.04 Yuan to 0.06 Yuan under full-load route conditions.

In contrast, the cost of less-than-container load (LCL) bulk shipping is usually 2.5 to 3.2 times that of full-container shipping, and the breakage rate will increase by about 1.2%.

In a 50MW-level ground power station project, by chartering more than 200 flatbed trucks of 17.5 meters for land transportation, the freight per kilometer can be reduced from 12 Yuan to 9.5 Yuan.

This logistics scale effect allows the cost of inter-provincial distribution to fall from 3% to within 1.8% of the total system budget.

Improving container utilization from 85% to 98% can reduce transport costs per watt by 0.015 Yuan. Port storage fees can be waived for a free period of 15 to 20 days during the agreement period due to large volumes, saving about 2% in logistics surcharges.

During large-scale shipments, the insurance rate per module drops from 3 per thousand to 1.5 per thousand, directly saving 50% in risk protection expenses.

Automated vertical warehouses are used in the storage phase, and the storage capacity per square meter is 3 times higher than that of ordinary warehouses, keeping the monthly inventory cost per module below 0.5 Yuan.

For export projects, large-scale customs declaration can adopt the "declare in advance, refund upon entry" mode. Capital turnover efficiency is improved by 25%, and annual interest expenses are reduced by about 1.5 million to 3 million Yuan.

This synergy of logistics and finance makes the cost, insurance, and freight (CIF) price of polycrystalline modules in overseas markets extremely competitive.

High working efficiency 

At a large-scale photovoltaic power station site of more than 100 MW, mechanized bracket installation speed reaches 1.5 MW to 2.2 MW per day, which is a 40% improvement in construction efficiency compared to small projects below 5 MW.

Since polycrystalline modules have uniform specifications and weights constant between 22 kg and 25 kg, a single worker's daily module mounting volume can be stable at 120 to 150 pieces.

Due to the use of mass-customized special cables and junction boxes, the cable loss rate per watt is reduced from 1.5% to about 0.8%, saving material costs of about 12,000 Yuan per megawatt.

Standardized construction processes have reduced the EPC (Engineering, Procurement, and Construction) management fee per watt by 0.05 Yuan to 0.1 Yuan.

Centralized installation reduces labor costs per watt to below 0.18 Yuan. Standardized O&M (Operations and Maintenance) management reduces the number of O&M personnel per megawatt from 1.2 to 0.5, with annual operating costs falling by 22%.

Large-scale power stations are usually equipped with centralized inverters with a single-unit capacity of 3.125 MW, which is 0.03 Yuan to 0.05 Yuan cheaper in unit price per watt than the string inverters used in distributed projects.

Since the voltage-temperature coefficient of polycrystalline modules is relatively stable, the number of DC combiner boxes can be reduced by 5% in large arrays, thereby reducing the Balance of System (BOS) cost by 0.02 Yuan.

Infrared thermal imaging inspections in annual maintenance are performed by drone swarms, shortening the inspection cycle per megawatt from 3 days to 20 minutes, and the accuracy of data analysis is improved to 99.9%.

This large-scale O&M model ensures that the system availability rate over the 25-year life cycle of the power station always remains higher than 99.5%.

Balance of System Costs

Lower bracket costs

The mainstream sizes of polycrystalline modules are usually fixed at 1960 mm x 992 mm x 40 mm. This highly standardized specification allows more than 95% of global universal aluminum alloy bracket systems to be directly adapted without customization.

The weight of a single module is stable at 22.5 kg to 23.5 kg. A single installation worker can complete the arrangement and locking of 40 to 60 modules within an 8-hour workday.

Since the module frame uses 30 mm to 35 mm 6063-T5 hard aluminum material, its compressive strength can withstand a static snow load of 5400 Pascals on the front, which reduces the amount of steel used per square meter of bracket by 1.2 kg to 1.8 kg.

In a 10 megawatt ground power station project, the unit procurement price of standardized brackets is usually maintained at 0.15 Yuan to 0.22 Yuan RMB per watt, which saves 12% in material costs compared to brackets for specially-shaped modules.

The foundation hole positions of the bracket system are usually set at a fixed distance of 990 mm or 1400 mm, adapting to 10 mm diameter M8 stainless steel bolts, and the installation error of a single array can be controlled within 2 mm.

Using fixed-tilt brackets for polycrystalline modules, the amount of steel used is about 35 kg to 45 kg per kilowatt. When the steel market price is 4500 Yuan per ton, the bracket cost per watt is about 0.16 Yuan to 0.2 Yuan.

Due to the voltage characteristics of polycrystalline modules, a single series array usually contains 18 to 22 panels. This design allows the utilization rate of a 100-meter long bracket beam to reach more than 98%.

Reducing the variety of bracket parts can shorten the on-site secondary processing time by 15%, shortening the civil construction cycle of the entire EPC project by about 10 to 14 days.

Save on cables

The open-circuit voltage (Voc) of polycrystalline modules is usually between 45 volts and 47 volts, and the operating current (Imp) is maintained at 8.5 amperes to 9.2 amperes, which makes 4 square millimeter DC-specific cables the most economical choice.

Within a DC transmission distance of 100 meters, the voltage loss percentage of 4 square millimeter cables is strictly controlled within 1.5%, ensuring a power transmission efficiency of over 98.5%.

Compared to high-current modules that need to upgrade to 6 square millimeter cables, adopting a polycrystalline solution can reduce the procurement cost per meter of cable by 0.8 Yuan to 1.2 Yuan RMB.

In a 10-megawatt project, the total length of DC cables usually reaches 50 km to 80 km. Choosing cable specifications that adapt to polycrystalline can save about 40,000 to 90,000 Yuan in the material budget.

The output power of a single string of modules is usually in the range of 6 kilowatts to 8 kilowatts, adapting to 1000-volt grade MC4 waterproof connectors, with contact resistance kept below 0.5 milliohms.

This current load characteristic allows the fuse rated current of the DC combiner box to be set at 15 amperes, reducing the heat loss of modules by 20% compared to high-current solutions.

In a 100 megawatt project, as the current density distribution is uniform, the width of the cable tray can be reduced by 10%, and the auxiliary material cost per meter of tray is reduced by 5 Yuan to 8 Yuan.

This adaptability of electrical parameters has reduced the line aging rate by 0.3% over the 25-year operation period, allowing an extra 12,000 to 25,000 kWh of electricity to be produced each year.

Easy to match inverters

The maximum power point tracking (MPPT) voltage range of polycrystalline modules is usually between 30 volts and 40 volts, which can perfectly match more than 90% of the string or centralized inverters on the market.

Centralized inverters have a rated input voltage of 1000 volts or 1500 volts. Polycrystalline arrays can stabilize the bus voltage at the 800-volt rated operating point through a series combination of 22 strings, with inverter efficiency as high as 98.5% to 99%.

With the DC/AC Ratio set at 1.2 to 1.3, a 3.125 megawatt inverter can be connected to about 3.8 megawatts of polycrystalline panels.

This ratio scheme is easier to control thermal overload than the monocrystalline scheme, extending the inverter's service life by 2 to 3 years.

The procurement cost per watt of inverters has dropped to 0.12 Yuan to 0.18 Yuan RMB in 2024. The low voltage fluctuation characteristics of polycrystalline systems reduce the compensation pressure on inverter capacitors.

Within the MPPT full-load voltage range of 500 volts to 850 volts, the operating time of the polycrystalline system accounts for more than 92%, which increases the low-light response gain by 3% compared to high-voltage systems.

Since the short-circuit current of polycrystalline modules is small, there is no need to install expensive DC shunts or high-precision current sensors, reducing the monitoring cost for a single inverter by about 500 Yuan.

This high degree of compatibility gives system integrators a price bargaining space of more than 15% when selecting models and ensures a grid connection success rate of 99.9%.

Efficient land use

In areas where land rent is 600 Yuan to 1000 Yuan per mu, polycrystalline modules maintain the land utilization rate (GCR) in a scientific range of 35% to 45% through optimized spacing design.

A 1 MW polycrystalline power station occupies about 25 mu to 30 mu. Although it occupies 10% more area than high-efficiency modules, its yield per mu is about 4% higher.

This is because the low unit price of polycrystalline modules offsets the increase in land costs, keeping the land amortization cost per kWh below 0.02 Yuan.

Over the 25-year lease period, the total land expenditure of projects using polycrystalline panels only fluctuated by 0.5 percentage points in the overall IRR (Internal Rate of Return) model.

The flatness requirement for on-site construction is that the drop per 10 meters should not exceed 5 centimeters, and the flexible adjustment range of the polycrystalline bracket system reaches plus or minus 150 millimeters.

This topographic adaptability reduces earthwork by 20%, saving excavation and backfilling costs of about 8000 Yuan to 15,000 Yuan per megawatt.

At an installation slope of 30 degrees, the distance from the bottom of the module to the ground is maintained at 500 mm to 800 mm, effectively avoiding more than 90% of weed shading.

Since the temperature coefficient of polycrystalline panels is about -0.39%/℃, their power loss caused by high summer temperatures is 2.5% lower than that of closed installations when running in well-ventilated open sites.

Low maintenance costs

The 3.2 mm tempered glass on the surface of polycrystalline modules has a light transmittance of more than 92%, and its self-cleaning coating can reduce dust adsorption by 15%.

In arid regions, cleaning is only required 2 to 3 times a year, and the cost of a single cleaning is controlled at 0.005 Yuan to 0.008 Yuan per watt.

As the modules do not have complex overlapping busbar structures, the occurrence of hotspots in infrared thermal imaging inspections is lower than 0.1%, reducing troubleshooting hours on-site by 30%.

A 25-year linear power guarantee means the annual O&M budget only needs to reserve 0.5% to 0.8% of the total investment, and the average annual O&M cost per megawatt is about 30,000 Yuan to 45,000 Yuan.

The PID (Potential Induced Degradation) suppression capability of polycrystalline modules shows a power decay of less than 2% after a 96-hour test in an environment of 85 degrees Celsius and 85% humidity.

This stability means the system does not need to be equipped with expensive anti-PID repair devices, saving about 1500 Yuan in hardware configuration costs at the inverter end.

As the frame adopts an anodic oxidation process with an oxide film thickness greater than 15 microns, it can operate stably for 25 years in a salt spray C5 corrosive environment without loosening at bracket connections.

This extremely low long-term maintenance requirement ensures that the project's cash flow income after 10 years is more than 2.8% higher than expected.