Solar PV supply chain map: who makes each part, and where
A solar module is a sheet of silicon cells laminated between glass and a backsheet, framed in aluminum, with a junction box on the back. Each part has its own makers, and the cells have a chain of their own behind them: wafers, polysilicon, metallurgical silicon, quartz.
The rules that decide whether a module earns a tax credit look at who owns each of those makers, not just the brand on the frame. One part from the wrong owner can change the answer for the whole project.
The Verdex solar map shows the companies at every step of this chain, where their plants are, and how each stands under the rules that apply to the sector. Each step below opens its own page: what happens at that step, who does it, and where. How a solar module is made, step by step.
Raw Extraction
- Quartz & Silica Mining: High-purity quartz and silica sand are extracted from deposits. Quartz feeds the silicon chain; silica sand also feeds glass production.
- Silver Mining: Primary and by-product silver mining. Silver is essential to solar cell metallization paste (~10% of global silver demand).
- Soda Ash Production: Soda ash (sodium carbonate) is mined (trona) or synthesized (Solvay process); a key flux in flat-glass manufacturing for solar cover glass.
Intermediate Processing
- Metallurgical Silicon: Quartz is reduced with carbon in submerged arc furnaces to produce metallurgical-grade silicon (~98% purity).
- Polysilicon Refining: MG-Si is purified to solar-grade polysilicon (>99.9999%) via Siemens process or fluidized bed reactor.
- Silver Refining: Mined silver is refined into high-purity silver powder and flake.
- Silver Paste & Metallization: Refined silver is formulated into conductive pastes used to screen-print electrodes on solar cells. Critical bottleneck material.
Core Components
- Quartz Crucibles: High-purity quartz fused into crucibles used to grow monocrystalline silicon ingots. Consumable per ingot pull.
- Ingot Growth & Wafer Cutting: Polysilicon is melted and grown into monocrystalline or multicrystalline ingots, then sliced into thin wafers via diamond wire saws.
- Solar Cover Glass: Low-iron, AR-coated patterned cover glass for the front of the module — melted from high-purity silica sand with soda-ash flux.
- Encapsulants: EVA and POE encapsulant sheets that laminate and insulate the cells between glass and backsheet.
- Backsheets: Polymer backsheets (Tedlar / PVDF / PET) that protect and electrically insulate the rear of the module.
- Aluminum Frames: Anodized aluminum frames that give the laminate mechanical rigidity and a mounting edge.
- Junction Boxes: Junction boxes with bypass diodes and cable terminations; combiner and enclosure variants for module and string wiring.
- Ribbon & Interconnect: Tinned-copper ribbon and interconnect wire that series-connect cells into strings.
- Thin-Film Absorber Materials: CdTe and CIGS absorber materials for thin-film modules.
Module & BOS
- Module Assembly: Cells are strung, laminated between glass and backsheet with encapsulant, framed, and fitted with a junction box.
- Inverters & Power Electronics: Convert DC from the array into grid-quality AC. Strings, centrals, microinverters, hybrid solar+storage inverters, DC optimizers.
- Trackers & Racking: Single- or dual-axis trackers and fixed-tilt racking — the steel and aluminum structures mounting modules to the ground or roof.
- Installation: Site preparation, mechanical mounting, and electrical interconnection that deliver installed capacity.
- MV Transformers: Medium-voltage step-up transformers that connect the plant to the grid. Plant-level balance-of-system; feeds installation.
- Plant Controls: Plant-level controls: power plant controllers (PPC), BMS/EMS, and SCADA that coordinate the array. Feeds installation.