Solar Energy Glossary Solar Terms Explained

A unit of power: how much electricity flows at one moment. Your system’s size (5KW, 10KW) is its maximum generating power under good sun.

A unit of energy: 1KW flowing for one hour. Your bill counts these one “unit” on a Pakistani bill is exactly one kWh.

The total power your appliances draw at a moment. A 1.5-ton inverter AC pulls ~1.2-1.8KW; find your running load with the load calculator.

The maximum load your DISCO connection is approved for. It matters because your net-metered system capacity is capped at it.

The type of grid connection. Single-phase suits systems up to ~5KW; larger systems and net metering generally require 3-phase.

Pakistan’s stepped billing: cross 200, 300 or 700 units in a month and every band costs sharply more. Self-consumed solar units knock out the most expensive slabs first.

Solar connected to the grid with no battery: lowest cost, best ROI, but shuts off during load-shedding. See on-grid systems.

Solar + battery + grid via a hybrid inverter: bill savings plus backup through outages the most popular choice for Pakistani homes. See hybrid systems.

Independent solar + battery with no grid connection, for farms, tube-wells and remote sites. See off-grid systems.

The scheme letting rooftop systems export surplus power to the grid through a bi-directional meter. Regulated by NEPRA and processed by your DISCO full guide.

The current NEPRA Prosumer framework: imported units are billed at your tariff while exported units earn a separately notified rate. It rewards self-consumption over export.

The meter that records imports and exports separately; installed by your DISCO during net-metering approval.

Your distribution company: K-Electric (Karachi), LESCO (Lahore), IESCO (Islamabad/Rawalpindi), PESCO (Peshawar), MEPCO, FESCO, GEPCO, HESCO and others.

The National Electric Power Regulatory Authority sets tariffs and the prosumer/net-metering regulations.

The Alternative Energy Development Board, which issues the small generation licence in the net-metering file.

Scheduled grid outages the single biggest reason Pakistani buyers choose hybrid over on-grid.

Using your solar power as it’s generated instead of exporting it. Under net billing, the highest-value unit is the one you use yourself.

The physics of converting light to electricity; a solar panel is a PV module.

A bankability ranking of manufacturers (Jinko, Longi, Canadian, JA, Trina) the practical shorthand for panels whose warranties will actually be honoured.

A-grade modules pass full factory QC; B-grade are cosmetically or electrically flawed seconds, widely re-labelled and sold cheap in Pakistan. Verify serials before you buy.

Today’s mainstream monocrystalline cell tech: efficient and proven.

The newer cell generation with higher efficiency, lower degradation and better heat behaviour ideal for Pakistani summers.

Generates from both faces, picking up reflected light beneath useful on elevated and carport structures.

The percentage of sunlight converted to power (modern Tier-1: ~21-23%). Higher efficiency means more watts per square foot of roof.

How much output drops per °C above 25°C. The lower the number, the better the panel holds output on a 45°C Karachi roof.

The slow annual loss of panel output (~0.4-0.55%/year on Tier-1). Warranties guarantee ~85-87% output remains after 25 years.

Early-life and temperature-related degradation effects; quality N-type panels largely eliminate them.

A panel’s rated output under standard test conditions the “580W” on a 580-watt panel.

Converts the panels’ DC into the AC your home uses; the brain of the system. Compare types and brands at solar inverters.

The standard on-grid inverter type, wiring panels in series “strings”.

Manages panels, battery and grid together, switching to backup instantly during outages.

The inverter circuit that continuously finds the panels’ best operating point. More MPPTs = more flexibility for roofs facing different directions.

Installing more panel capacity than inverter rating (e.g. 6KW of panels on a 5KW inverter) to fill its output curve across the day standard, sensible practice within brand limits.

Absorbs voltage spikes from the grid and nearby lightning essential on Pakistan’s spike-prone distribution lines.

The standard locking DC connector between panels; genuine ones prevent the loose joints behind most rooftop arc faults.

Bonding panels, structure and inverter to an earth rod so faults trip breakers instead of energising frames.

Dust-tight, water-jet-resistant enclosure rating the minimum for outdoor-mounted equipment.

The controller that lets solar power drive water pumps at varying speeds the heart of a solar tube-well.

The modern solar battery: thousands of cycles, deep discharge, no maintenance. Compare options on the hybrid page.

The traditional lead-acid option: cheaper upfront, shorter life, needs topping up.

How much of a battery’s capacity is usable per cycle (~90% lithium vs ~50% tubular).

How many charge/discharge rounds a battery survives; the honest way to compare battery value.

How long the battery can carry your chosen loads size it with the battery calculator.

The itemised equipment list in a proper quote. If a quote won’t itemise, walk away.

Engineering, procurement and construction turnkey delivery of larger commercial/industrial plants.

Operations & maintenance / annual maintenance contract scheduled cleaning, inspection and repair.

How long savings take to repay the system cost: typically 2.5-4 years in Pakistan compute yours with the calculator.

Return on investment over the system’s 25-year life; solar’s is among the best of any home improvement in Pakistan.

The total rated panel capacity of a system, e.g. a “10KW system” see packages.

The everyday Pakistani term for a solar panel; prices tracked on the solar panel price page.