Solar procurement glossary
Plain-English definitions for terms buyers see in Pakistani solar proposals, policy updates, and approval conversations.
AC/DC ratio
The relationship between inverter AC capacity and solar panel DC capacity. A higher DC side can improve inverter utilization, but excessive oversizing can clip production.
AEDB
The Alternative Energy Development Board, a public-sector body historically involved in renewable-energy policy and market development in Pakistan. Buyers may see older documents or supplier materials reference AEDB approvals or policy context.
BoS
Balance of system: the non-panel and non-inverter parts of a solar installation, including structure, cabling, protection devices, earthing, monitoring, and installation accessories.
Commissioning
The testing and handover stage after installation. A proper commissioning record should confirm that the system was installed, checked, energized, monitored, and handed over with the right documents.
CT ratio
Current-transformer ratio, used in metering and monitoring to scale electrical current readings. Incorrect CT selection or installation can make monitoring and billing data unreliable.
DC isolator
A switch used to disconnect the direct-current side of a solar system. Buyers should check that isolation, protection, and labeling are included rather than assumed.
DISCO
A distribution company responsible for local electricity distribution and utility-side processing. In Pakistan, DISCO approval and meter coordination can affect project timelines.
Distributed generation
Electricity generation installed close to the point of use, such as rooftop or onsite solar. Pakistan's prosumer rules use distributed-generation language for grid-connected customer generation.
Earthing
The grounding system that helps protect people and equipment from electrical faults and lightning-related risk. Weak earthing scope is a common hidden gap in solar quotations.
Export units
Electricity generated by a solar system and sent to the grid after onsite consumption. Under net billing, export units are valued separately from imported units.
Generation estimate
The supplier's estimate of how many kilowatt-hours the system will produce over a month or year. Buyers should ask for the assumptions behind the estimate, not just the final number.
Grid-tied system
A solar system connected to the utility grid. It usually depends on grid availability and requires utility-side approval for export or prosumer treatment.
Hybrid inverter
An inverter that can work with solar panels and batteries. Hybrid systems are useful when backup or load shifting matters, but they add cost and should be justified carefully.
Interconnection
The technical and administrative process of connecting a distributed-generation system to the utility network. Interconnection responsibility should be clear before award.
kW
Kilowatt, a unit of power. In proposals it is often used for system capacity, inverter capacity, or sanctioned load, so buyers should check which capacity the supplier means.
kWh
Kilowatt-hour, a unit of energy. Bills, generation estimates, imports, exports, and savings models usually depend on kWh, not only system size in kW.
Load flow study
A technical study used to assess whether the local network can safely accept a proposed system. Current rules make this especially relevant at larger system sizes.
MPPT
Maximum power point tracking, an inverter function that optimizes solar panel output under changing light and temperature conditions.
NAEPP
National Average Energy Purchase Price. In current net-billing discussions, it is a key reference for valuing exported electricity.
NAPPP
National Average Power Purchase Price. A broader power purchase price reference that can help buyers understand the spread between import-side and export-side assumptions.
NEPRA
The National Electric Power Regulatory Authority. NEPRA issues and updates regulations that shape prosumer, net-billing, and electricity-sector rules in Pakistan.
Net billing
A billing arrangement where imported electricity and exported electricity are accounted for separately. Imports are billed at the applicable tariff, while exports are purchased at a defined purchase-price basis.
Net metering
A legacy term often used in Pakistan for solar export arrangements. Buyers should confirm whether a proposal refers to an older protected agreement or the current prosumer framework.
O&M
Operations and maintenance. O&M can include cleaning, inspection, monitoring review, fault response, and preventive maintenance after commissioning.
Payback period
The estimated time it takes for savings to recover the project cost. Payback depends on tariff, self-consumption, export value, generation, downtime, maintenance, and financing assumptions.
Performance ratio
A measure of how much usable energy a solar system produces relative to its theoretical output. It reflects losses from temperature, dust, wiring, downtime, and other real-world factors.
PV
Photovoltaic, the technology used by solar panels to convert sunlight into electricity. PV is often used in technical documents and regulatory language.
Prosumer
A customer who both consumes electricity and produces electricity through distributed generation such as solar.
Protection devices
Electrical safety components such as breakers, fuses, surge protection, isolators, and earthing-related equipment. They should be explicitly scoped in the quotation.
Sanctioned load
The approved connected load for a premises. In Pakistan, proposed distributed-generation capacity can be constrained by sanctioned load and network conditions.
Self-consumption
Solar electricity used onsite instead of exported. Under net billing, higher self-consumption usually makes the economics more resilient.
Single-line diagram
A simplified electrical drawing showing the main components and connections of a system. It is commonly required for technical review and approval submissions.
SPD
Surge protection device. SPDs help protect equipment from voltage surges and should be specified clearly on the AC and DC sides where required.
STC
Standard Test Conditions, the lab basis used to rate panel output. Real-world output is usually lower because actual temperature, dust, orientation, and shading differ from lab conditions.
Tier 1
A finance and bankability label often used for solar panel manufacturers. It is not a direct guarantee of panel quality, warranty service, or local support.
Turnkey
A project scope where the supplier is responsible for delivering a complete working system. Buyers should still verify exactly what turnkey includes and excludes.