B2B solar knowledge base

Solar PV glossary for B2B buyers

Plain-language definitions for module, testing, procurement, trade and project terms, with the document boundaries buyers should verify before relying on them.

Content and official sources reviewed 23 August 2026

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Solar module inspection supporting model and evidence review

Short answer

A solar term is useful only when it is tied to the right model, document and transaction.

This glossary explains common usage. The exact model datasheet, current certificate scope, accepted test evidence, contract, quote and PI control a purchase. IEC qualification is not a lifetime promise, Tier 1 is not a product certificate, and a technology label is not a complete quality assessment.

JUSTSOLAR can review OEM and private-label requirements under NDA. We do not publish named OEM customers or treat confidential customer relationships as product evidence.

Module and electrical terms

Terms used on module datasheets, test records and system designs.

PV module: An assembled photovoltaic product that converts light into direct-current electricity. The exact model designation controls which datasheet and evidence apply.
Solar cell: The semiconductor device inside a module that converts light into electrical energy. A module combines interconnected cells with protective materials and electrical connections.
DC (direct current): Electric current with one direction of flow. PV modules produce DC electricity before an inverter converts it for an AC system.
AC (alternating current): Electric current that periodically changes direction. Inverters convert PV-generated DC into AC with parameters required by the connected system or grid.
Pmax (maximum power): The maximum electrical power on a measured current-voltage curve under stated test conditions. Use the model datasheet and flash record for the declared basis.
Voc (open-circuit voltage): The voltage measured when no load is connected. Designers use the model value and temperature assumptions when checking string voltage limits.
Isc (short-circuit current): The current measured when the module output terminals are shorted under stated conditions. It is one input to conductor and protection design.
I-V curve: A current-versus-voltage trace for a PV device under stated measurement conditions. The curve shows Voc, Isc and the maximum-power operating point.
STC (standard test conditions): A standardized reference basis used to rate PV modules. STC is a comparison condition, not a forecast of field output at a specific site.
Irradiance: Solar power incident on a surface per unit area. Measurement plane, sensor, calibration and time interval matter when using irradiance for performance analysis.
String: A group of PV modules connected electrically in series. The selected models, quantity and design temperatures determine the string voltage and current basis.
MPPT (maximum power point tracking): An inverter or controller function that adjusts the operating point to seek available PV power. Its usable range must be checked against the array design.
Bypass diode: A module junction-box component that provides an alternate current path across a protected cell group under certain operating conditions. Its presence does not eliminate shading or defect risk.
Hot spot: Localized heating in a PV module or connection. Root causes and acceptance require inspection and testing; a bypass diode alone is not proof that the risk is controlled.
EL inspection: Electroluminescence imaging used to reveal cell and interconnection features that may not be visible in normal light. Image conditions, timing and acceptance criteria must be agreed.
Flash test: A controlled electrical performance measurement using a solar simulator. Buyers should match the record to the model and serial or production-lot scope.

Technology and performance terms

Labels that describe module construction or behavior, not a universal quality ranking.

Monofacial module: A module whose declared power rating is based on light received by its front side. Rear construction and installation still need model-specific review.
Bifacial module: A module designed to convert light received on both front and rear sides. Rear-side contribution depends on the model, mounting, ground reflectance, shading and site geometry.
Bifaciality factor: A ratio comparing a rear-side electrical characteristic with the corresponding front-side characteristic under a defined method. It is not the same as site energy gain.
Albedo: The fraction of incident light reflected by a surface. It is one input to bifacial yield modelling and should be measured or justified for the project site.
P-type cell: A cell whose base semiconductor uses P-type conductivity. The label alone does not establish efficiency, degradation, warranty or project suitability.
N-type cell: A cell whose base semiconductor uses N-type conductivity. Buyers should still compare the complete module design, evidence and commercial scope.
PERC: Passivated emitter and rear cell technology used to improve cell performance. PERC identifies a cell architecture, not a complete module specification.
TOPCon: Tunnel oxide passivated contact cell technology. Model output, construction, qualification and warranty remain model-specific.
HJT: Heterojunction cell technology combining crystalline silicon with thin semiconductor layers. The technology name does not by itself prove a temperature coefficient or field yield.
Half-cut cell: A cell divided into smaller electrical sections before module assembly. The complete circuit and module design determine electrical and shading behavior.
Glass-glass module: A module construction with glass on both front and rear sides. Glass thickness, encapsulation, edge sealing, frame and qualification scope remain important.
Temperature coefficient: The declared rate at which an electrical characteristic changes with temperature under a stated basis. Use the coefficient for the exact model and parameter.
Degradation: A change in module performance over time. Actual behavior depends on design, environment and operation; qualification tests do not quantitatively predict service life.
LID (light-induced degradation): A light-exposure-related change in PV device performance. Its mechanism, magnitude and test method depend on the cell and module technology.
PID (potential-induced degradation): A performance change associated with electrical potential and environmental stress. Test scope and system conditions should be reviewed rather than inferred from a label.

Procurement and evidence terms

Words buyers should connect to exact documents, named places and accepted commercial terms.

Model designation: The exact identifier that connects a product to its datasheet, label, certificate, test evidence, packing record and order documents.
Datasheet: A manufacturer document declaring product characteristics and conditions. It is not by itself a certificate, test report, stock confirmation or formal offer.
Certificate scope: The models, applicant, manufacturer, production site, standard edition, annexes and status covered by a certificate. Similar branding does not extend that scope.
Test report: A record of testing for identified samples, methods and conditions. Buyers should verify its link to the offered model and the purpose for which it is being relied on.
BOM (bill of materials): The defined materials and components used for a product configuration. Any controlled BOM or change-management requirement must be written into the accepted order scope.
Traceability: The ability to connect a product, lot or serial reference with relevant materials, manufacturing and inspection records at the agreed level.
OEM or private label: A supply arrangement where products are made to an agreed customer specification or brand presentation. Named OEM customers remain confidential under NDA.
Tier 1: A third-party bankability classification used in parts of the solar-finance market. It is not an IEC certificate, product-quality guarantee or substitute for due diligence.
Bankability: The degree to which lenders, investors and other stakeholders consider a company, product or project financeable. The assessment is transaction- and project-specific.
RFQ (request for quotation): A buyer request that defines the product, quantity, destination and required commercial or evidence basis so suppliers can prepare comparable responses.
MOQ (minimum order quantity): The smallest quantity a supplier will review or accept for a defined product and production plan. It must be confirmed for the current request.
PI (pro forma invoice): A commercial document setting out the accepted pre-shipment transaction basis. Only the issued PI and referenced documents define JUSTSOLAR order terms.
Warranty: Written obligations, exclusions, remedies, conditions and claim procedures for an identified product and sale. A marketing summary does not replace the applicable warranty document.
Incoterms 2020: ICC rules that allocate selected delivery obligations, costs and risks between seller and buyer. They do not set product quality, payment method or ownership transfer by themselves.
FOB (Free On Board): An Incoterms 2020 sea or inland-waterway rule where delivery and risk transfer occur on board the vessel at the named port of shipment. Use a named port and edition.
CFR (Cost and Freight): An Incoterms 2020 sea or inland-waterway rule where the seller pays freight to the named destination port while risk transfers when goods are on board at shipment.
CIF (Cost, Insurance and Freight): A CFR-based Incoterms 2020 rule that also requires seller-arranged insurance at the rule's stated level. Extra coverage must be agreed when needed.
CBAM: The EU Carbon Border Adjustment Mechanism for listed imported goods. The current official sector list does not make every finished PV module automatically in scope; classification and law must be checked.

Project and system terms

Terms used when modules become part of a designed, contracted and operated PV asset.

BOS (balance of system): PV-system equipment and work beyond the modules, such as structures, inverters, cables, protection, monitoring and installation interfaces.
Inverter: Equipment that converts DC electricity into AC and may provide control, protection and grid-support functions. Model and grid-code fit require project review.
EPC: Engineering, procurement and construction. The contract must define the work, interfaces, acceptance, exclusions and responsibility of each party.
Commissioning: The planned inspection, testing, documentation and acceptance process used to show that an installed system meets its approved project requirements.
O&M: Operations and maintenance activities for an operating asset. Scope, response, monitoring, spares and performance mechanisms belong in the project agreement.
SCADA: Supervisory control and data acquisition infrastructure used to monitor and, where designed, control plant equipment. Data ownership and access should be defined.
BESS: Battery energy storage system. Chemistry, power, energy, controls, safety, transport and grid requirements are project-specific.
PPA (power purchase agreement): A contract governing the sale and purchase of electricity from a project. Price structure, term, volume, settlement and risk allocation are negotiated terms.
PR (performance ratio): A normalized PV-system performance indicator calculated under a defined method and data basis. It is not meaningful without agreed inputs, exclusions and periods.
LCOE (levelized cost of energy): A metric relating lifecycle costs to lifecycle energy under stated financial and technical assumptions. Results are comparable only when the method and inputs align.

Five RFQ details identify the supply context

Send these five fields before asking whether a definition, model or document applies to your purchase.

01
Buyer type
Distributor, installer, agent, EPC or project buyer
02
Country
The market where the product will be used or resold
03
Product
Module, cell, component or system requirement
04
Quantity
Pieces, containers, MW or repeat forecast
05
Destination port
The named port for the requested delivery basis

Official sources and scope

These sources anchor terminology, qualification, safety, trade and market context. They do not prove that a particular model, factory, certificate, price, stock position or delivery term applies to an order.

IEC TS 61836:2025 - Solar PV terminologyThe current IEC TC 82 reference for solar PV terms, definitions and symbols.IEC 61215-1:2021 - Design qualification and type approvalThe scope and limits of terrestrial PV module design qualification; test results are not a quantitative lifetime prediction.IEC 61730-1:2023 - PV module safety qualificationFundamental module-construction safety requirements and the boundary with national or regional codes.ICC - Incoterms 2020The official trade rules and guidance for allocating selected delivery costs, risks and obligations.European Commission - CBAM sectorsThe current official sector list and implementation guidance for the EU carbon-border mechanism.IEA PVPS - Trends in Photovoltaic Applications 2025Independent market and technology context through 2024; it does not establish a model-specific product claim.

Buyer questions

Does Tier 1 prove module quality or certification?

No. Tier 1 is a third-party bankability classification, not an IEC certificate or product-quality guarantee. Review the exact model, manufacturer, production site, certificate scope and transaction evidence.

Does an IEC 61215 or IEC 61730 reference automatically cover every model and factory?

No. Verify the certificate holder, manufacturer, production site, listed models, standard edition, annexes and current status. National or regional requirements may also apply.

Are FOB, CFR and CIF interchangeable?

No. They allocate selected costs and risks differently, and all three require a named place or port and stated rules edition. The sale contract must define the remaining commercial terms.

Does a datasheet prove destination-market compliance?

No. A datasheet declares product characteristics. Destination compliance may require certificates, registrations, labels, test evidence and importer checks tied to the exact model and market.

What should a buyer send for a qualified RFQ?

Send buyer type, country, product, quantity and destination port. Add the required model, evidence, inspection and delivery basis when already known.

Related buyer guides

Bankability evidence guide Quality and compliance Certificate review Module warranty guide Solar Incoterms guide Comparable quote checklist

Turn the terminology into a reviewable RFQ

Frank or the Director reviews product fit after receiving the five buying details. Specification, price, availability, lead time, certification, warranty and payment terms are confirmed only through the formal offer and PI path.