Solar & Electricity Glossary — MyEnergyHub

The Pakistan electricity and solar sectors use a layered vocabulary — federal regulator (NEPRA), nine distribution companies (DISCOs), provincial subsidy schemes, AEDB licensing, and the international solar engineering lexicon. This glossary is the practical subset you will encounter when reading a bill, requesting a solar quote, or applying for net-metering.

A

AEDB: Alternative Energy Development Board — the federal Pakistan body that licenses renewable-energy EPCs, vendors and net-metering installers. Only AEDB-certified contractors qualify for net-metering and subsidy schemes.
AMC: Annual Maintenance Contract — a yearly service agreement for solar systems covering cleaning, inverter health checks, connection torquing and reporting. Typical Pakistan price: Rs 15,000–25,000/year for a 10 kW residential system.
Agri Tariff (D1): NEPRA-notified agricultural tariff category for tube wells and farm pumping. In 2026 ranges roughly Rs 8–18 per unit by time-of-use, plus FPA, GST and surcharges.
Arrears: Unpaid amount from previous bills carried forward on the current DISCO bill. Late payment adds a 10% Late Payment Surcharge (LPS).
ATS: Automatic Transfer Switch — a contactor that switches the load between solar/battery, grid, and generator without manual intervention. Essential in hybrid systems for seamless load-shedding handover.

B

Battery DoD: Depth of Discharge — the percentage of a battery’s capacity that can be safely drawn down. LiFePO4 batteries support 80–90% DoD; tubular lead-acid batteries safely support only 50%.
Bidirectional Meter: A meter that measures both energy imported from the grid and energy exported to the grid. Required for net-metering and net-billing in Pakistan; replaces the standard single-direction meter.
Bill Reference Number: The 14-digit identifier on every Pakistan DISCO bill, unique to the connection. Used for online payment via 1Bill, JazzCash, EasyPaisa and bank apps.
BoS: Balance of System — every non-panel, non-inverter component of a solar system: mounting structure, DC and AC cables, MC4 connectors, fuses, breakers, surge protectors, earthing. Typically 12–18% of system cost in Pakistan.
Bus Bar: The thin metal ribbons on a solar cell that collect generated current. Modern Tier-1 panels use 9 to 12 bus bars; more is marginally better but rarely the deciding factor.

C

Capex: Capital Expenditure — the up-front installed cost of a solar system. Distinct from Opex (running cost). A 10 kW hybrid in Pakistan has Capex of Rs 16–19 lakh in 2026.
CT (Current Transformer): A device that scales down high currents for measurement. On Pakistan commercial and industrial meters, the meter reads through CTs and the bill applies a multiplication factor (MF) to compute actual units.
Circular Debt: The chain of unpaid liabilities across Pakistan’s power sector — DISCOs owe IPPs, IPPs owe fuel suppliers, government owes DISCOs. Funded indirectly through Debt Servicing Surcharge (DSC) on every bill.

D

DISCO: Distribution Company — the nine regional companies that distribute electricity in Pakistan (LESCO, IESCO, MEPCO, GEPCO, FESCO, PESCO, HESCO, QESCO, K-Electric).
DC (Direct Current): Electricity flowing in one direction, as produced by solar panels and stored in batteries. Converted to AC by an inverter for household use.
DSC: Debt Servicing Surcharge — a per-unit charge (Rs 3.23/unit in 2026) collected on all Pakistan bills to retire power-sector circular debt.

E

Earthing: A copper conductor connecting electrical equipment to ground. Required by Pakistani electrical code; protects against shock and lightning. Solar systems need separate panel-frame earthing and inverter earthing.
Electricity Duty (ED): A provincial tax of 1.5% on the energy cost line of every Pakistan DISCO bill. Collected by the DISCO on behalf of the province.
Energy Yield: Actual electricity produced by a solar system over a period, usually expressed in kWh/kWp/year. A Lahore rooftop typically yields 1,500–1,650 kWh/kWp/year.

F

FPA: Fuel Price Adjustment — NEPRA-notified monthly per-unit add-on covering actual fuel cost variation. In 2026 has ranged Rs 1.50–4.80/unit on LESCO, IESCO and MEPCO bills.
Financing Cost: Catch-all line covering debt-servicing surcharges, sometimes broken out as DSC. Applies to all categories except lifeline consumers.
Fixed Charges: Monthly per-kW charges based on sanctioned load, independent of units consumed. Pakistan domestic consumers above 5 kW sanctioned load pay Rs 1,000/kW/month in 2026.

G

GST: General Sales Tax — 17% federal tax applied to the sum of energy cost, FPA, QTA, fixed charges, electricity duty, Neelum-Jhelum surcharge and financing cost. Lifeline consumers exempt.
Grid-tied / On-grid: A solar system connected to the DISCO grid, without batteries. Exports surplus through net-metering. Cheapest and fastest payback configuration but provides no backup during outages.

H

Hybrid Inverter: An inverter that handles solar, battery and grid simultaneously, providing seamless backup. Standard for Pakistan residential installs given load shedding. Brands available: Growatt, Deye, Solis, Huawei, Inverex.

I

IDM (NEPRA): NEPRA Investigation & Decision Making process — the formal forum for consumer complaints unresolved at DISCO level. Decisions are binding.
IEC 61215: International standard for solar panel durability testing. Genuine Tier-1 panels carry IEC 61215 certificates specific to factory and model. Used to verify authenticity.
Inrush Current: The very high momentary current drawn by motors and capacitive loads at startup, often 5–8x running current. Inverter selection must account for inrush of AC compressors and water pumps.
Inverter: A device that converts DC (from panels or batteries) into AC for household use. Three types: string (on-grid), hybrid (solar + battery + grid), and microinverter (per panel).
IRR: Internal Rate of Return — the annualised yield of an investment over its life. A cash-paid 10 kW hybrid system in Pakistan in 2026 typically returns 22–28% IRR over 25 years.

K

kVA: Kilo-Volt-Ampere — apparent power, the product of voltage and current. Inverters and transformers are rated in kVA. For a unity-power-factor load, 1 kVA = 1 kW.
kW vs kWh: kW (kilowatt) measures power — how much energy is being used at a moment. kWh (kilowatt-hour, also called a “unit”) measures energy — kW multiplied by hours. A 1 kW load running 1 hour consumes 1 kWh.
kWp: Kilowatt peak — the rated DC output of a solar array under standard test conditions (1000 W/m², 25 °C). Pakistan rooftops typically deliver 1,500–1,700 kWh per kWp per year.

L

LiFePO4: Lithium Iron Phosphate — the dominant battery chemistry for residential solar storage in Pakistan in 2026. 6,000+ cycles at 80% DoD, much safer than NMC. Pylontech, Dyness, BYD and Phoenix brands all use LiFePO4.
Lifeline Tariff: Pakistan’s subsidised slab for the poorest consumers — under 50 units/month with sanctioned load under 1 kW. Tariff A1(02). Exempt from most surcharges and GST.
Load Shedding: Planned grid outages to balance supply and demand. Pakistan urban areas typically see 2–6 hours/day; rural areas 8–12 hours/day. Primary driver of residential battery and solar adoption.
Lugs: Crimped copper terminals at the end of DC and AC cables, where they connect to breakers, fuses and bus bars. Quality lugs (tinned copper, two-hole) prevent loose connections and fire risk.

M

MC4: The industry-standard solar DC connector. Always pair MC4-male with MC4-male and female with female. Never mix brands on the same junction — Stäubli, Amphenol and PV-CY all spec slightly differently.
Meter (Net / Gross / Bidirectional): Net meter records (export − import), gross meter records both separately, bidirectional meter measures both directions but bills under the applicable net-metering or net-billing scheme. Pakistan since 2017 uses bidirectional under NEPRA net-metering regulations.
MOSFET: Metal-Oxide-Semiconductor Field-Effect Transistor — the power switching device inside modern inverters. Failure of inverter MOSFETs is the most common warranty claim.
MPPT: Maximum Power Point Tracking — the algorithm in modern solar charge controllers and inverters that constantly adjusts voltage/current to extract maximum panel output, regardless of shading or temperature.
Multiplication Factor (MF): A whole-number multiplier on commercial DISCO meters with CTs. Common values: 10, 20, 40, 80, 200. A wrong MF can multiply your bill ten-fold; verify on your bill.

N

NEPRA: National Electric Power Regulatory Authority — the federal regulator of Pakistan’s electricity sector. Sets tariffs, approves licenses, runs complaints process, notifies FPA monthly.
Neelum-Jhelum Surcharge: A Rs 0.10/unit nationwide surcharge to repay the cost of the Neelum-Jhelum hydropower project in Azad Kashmir. Appears on every Pakistan DISCO bill.
Net Metering: Pakistan’s pre-2026 solar export scheme where each exported unit netted against an imported unit at retail tariff. Replaced for new applicants by net-billing in 2026.
Net Billing: The 2026 NEPRA scheme replacing net-metering for new applicants. Imports billed at retail tariff; exports compensated at NEPRA average buyback (Rs 11/unit). Existing net-metering connections continue under old terms.

O

OCV: Open Circuit Voltage — a panel’s output voltage when no load is connected. Typically 45–50 V for a 585 W panel. String OCV must stay below the inverter’s maximum DC voltage at lowest expected temperature.
On-grid: A solar system tied to the DISCO grid, without battery storage. Exports surplus through net-metering or net-billing. Lowest cost, but no backup during outages.
Opex: Operating Expenditure — the recurring annual cost of a solar system: cleaning, AMC, occasional repair. Pakistan residential solar opex is roughly 0.5–1% of capex per year.

P

Panel Orientation: For Pakistan (Northern Hemisphere), panels should face true south for maximum annual yield. Roof azimuth within ±15° of south loses less than 2%; east/west loses 10–15%.
PCC (Point of Common Coupling): The exact location where a customer’s solar system meets the DISCO grid — typically at the main breaker on the consumer side of the meter. NEPRA net-metering rules apply here.
Peak Sun Hours (PSH): The number of daily hours of equivalent full-strength sunlight (1000 W/m²) at a location. Pakistan averages: Karachi 5.1, Lahore 4.7, Islamabad 4.5, Multan 5.0, Bahawalpur 5.3, Quetta 5.4.
PV: Photovoltaic — the technology that converts sunlight directly to electricity. Standard term for solar electricity worldwide.
PSB Solar Finance: State Bank of Pakistan refinance scheme for solar loans, channeled through commercial banks. 2026 terms: up to Rs 25 lakh residential, 5–7 year tenor, KIBOR + 3% spread (~15.5% effective).

Q

QTA: Quarterly Tariff Adjustment — NEPRA-notified per-unit adjustment every three months to recover capacity payments and stranded power-purchase costs from the prior quarter. Typically Rs 1–3/unit on Pakistan bills.

R

RMG (Reverse Metering): Older informal term for net-metering — a meter that runs backwards when solar exports. Modern bidirectional meters separate import and export rather than spinning backwards.

S

Sanctioned Load: The maximum kW your DISCO has authorised at your premises, printed on every bill. Exceeding it on commercial meters triggers MDI penalties; on domestic above 5 kW, fixed charges of Rs 1,000/kW/month apply.
SCADA: Supervisory Control and Data Acquisition — the monitoring system used by DISCOs and large solar farms to remotely supervise equipment. In residential solar, the inverter app (Growatt ShinePhone, Solarman, Huawei FusionSolar) is a consumer-grade equivalent.
Solar Irradiance: Instantaneous solar power per square metre, measured in W/m². Pakistan mid-day clear-sky values reach 950–1050 W/m². Multiplied by panel area and efficiency to estimate output.
String: A series-connected group of solar panels feeding one inverter MPPT input. Each string has its own voltage and current; mixed-orientation panels should never share a string.
Surge Protector (SPD): A device that diverts lightning- and switching-induced voltage spikes to earth, protecting the inverter and controller. Mandatory on Pakistan solar installs, especially in monsoon-prone districts.

T

Tariff Slab: A consumption band with its own per-unit rate. Pakistan unprotected domestic 2026 slabs: 1–100, 101–200, 201–300, 301–400, 401–500, 501–600, 601–700, 700+ units. Each slab has a higher Rs/unit rate than the one before.
Three-Phase: A power-supply configuration with three live wires 120° out of phase, allowing higher loads with less current. Pakistan domestic above ~7 kW load and most commercial connections are three-phase.
Time of Use (ToU): A tariff structure where unit rates vary by time of day — peak hours (typically 6 PM–10 PM in Pakistan) cost more than off-peak. Applies to commercial and large domestic consumers; net-billing exports under ToU rates too.
TR (Tariff Reference): The NEPRA code printed on every DISCO bill defining which rate schedule applies — e.g. A1(03) unprotected domestic, A2 commercial, B1 industrial, D1 agricultural. A wrong TR is the most common silent overcharge.
TV Fee: A flat Rs 35 per month PTV (Pakistan Television Corporation) collection through electricity bills, mandatory for all domestic consumers above 1 kW sanctioned load since 1989.

V

Vmpp / Voc: Vmpp is the panel voltage at maximum power point under standard test conditions (typically 35–40 V on a 585 W panel). Voc is open-circuit voltage (45–50 V). Both must be respected when designing strings.
VFD: Variable Frequency Drive — a controller that varies AC motor speed by varying supply frequency. Standard for AC solar tube wells in Pakistan to match pump output to available panel power.

W

WAPDA: Water and Power Development Authority — historical parent of Pakistan’s power sector. Today operates only hydropower generation; DISCOs and NTDC handle distribution and transmission.

Still confused by a term?

Drop us a note through the contact page and we will add it to the next glossary revision. We update this page every quarter to track new NEPRA notifications, DISCO changes, and emerging solar terminology in Pakistan.

Last updated: 2026-05-17. Maintained by the MyEnergyHub Solar Team.