Solar, in plain words.

A

ACDB(AC distribution box)

The enclosure on the AC side of a solar system containing the breaker, surge protection and isolator between the inverter and your home's wiring.

ALMM(Approved List of Models and Manufacturers)

MNRE's list of approved solar module models and manufacturers. Modules used in government-supported schemes are generally required to be on it.

Anti-islanding

A safety function that shuts an on-grid inverter down when the grid fails, so it does not feed power into lines being repaired.Learn more

B

Bi-directional meter(Net meter)

An electricity meter that records both units imported from the grid and units exported to it. Required for net metering.Learn more

Bifacial module

A solar panel that generates from both faces, capturing light reflected onto its back. Gains are highest on elevated structures over light-coloured roofs.Learn more

Busbar

The thin metal strips printed on a solar cell that collect current. Modern cells use many thin busbars (multi-busbar) to reduce losses.

Bypass diode

A diode in the module junction box that lets current flow around a shaded or damaged group of cells, limiting power loss and hot-spots.

C

Capacity utilisation factor (CUF)

Actual annual generation divided by the maximum possible if the system ran at full rated power all year. Rooftop systems in Indore typically achieve around 16–17%.

CFA(Central Financial Assistance)

The central government subsidy for rooftop solar. Under PM Surya Ghar, homes receive up to ₹78,000.Learn more

D

DC:AC ratio

Array DC capacity divided by inverter AC rating. A ratio slightly above 1 (e.g. 1.1) improves morning and evening output with minimal clipping.

DCDB(DC distribution box)

The enclosure on the DC side containing fuses, surge protection and an isolator between the panels and the inverter.

DCR(Domestic Content Requirement)

Solar modules made with cells manufactured in India. Mandatory for PM Surya Ghar subsidised systems.Learn more

Degradation

The gradual loss of a module's output over time, typically 1–2% in year one and about 0.4–0.55% per year after that.Learn more

DISCOM

Electricity distribution company. Indore is served by MP Paschim Kshetra Vidyut Vitaran Company Ltd (MP West Discom, MPPKVVCL).

E

Earthing

Connecting metal parts and equipment to the ground so fault currents and surges have a safe path. Solar systems need earthing for frames, inverter and lightning arrester.Learn more

Efficiency (module)

The share of sunlight hitting a panel that becomes electricity. Modern mono modules are around 20.5–23% efficient.

Elevated structure

A raised solar mounting structure on tall columns that keeps the terrace usable underneath and lifts modules above shadows.Learn more

EVA(Ethylene-vinyl acetate)

The transparent encapsulant film that bonds and seals solar cells between the glass and backsheet. POE is an alternative with better moisture resistance.

Export

Solar electricity sent from your premises to the grid when generation exceeds consumption.

F

Feasibility approval

The DISCOM's technical approval that your connection can accept a rooftop solar system of the requested size.

H

Half-cut cells

Solar cells cut in half so each carries half the current, reducing resistive losses and the impact of partial shading.

Hot-spot

A cell that overheats because it is shaded or damaged while the rest of the module pushes current through it. Can permanently damage the module.

Hybrid inverter

An inverter that manages solar, a battery and the grid together, providing backup during outages.Learn more

I

Import

Electricity drawn from the grid into your premises.

Inverter

The device that converts DC power from solar panels into AC power for your home and the grid.Learn more

Irradiance

The power of sunlight reaching a surface, measured in watts per square metre (W/m²). Around 1,000 W/m² on a clear noon.

J

Junction box

The sealed box on the back of a module containing bypass diodes and the output cables with MC4 connectors.

K

kW(Kilowatt)

A unit of power. Solar system size is stated in kW (or kWp) — the maximum it can produce under standard test conditions.

kWh(Kilowatt-hour, 'unit')

A unit of energy — the 'units' on your electricity bill. A 1 kW system in Indore produces about 4 kWh a day.

kWp(Kilowatt peak)

The rated DC capacity of a solar array under standard test conditions (1,000 W/m², 25°C cells).

L

Lightning arrester

A rooftop rod with its own earth connection that gives lightning a controlled path to ground, protecting the system and building.

Load enhancement

An application to the DISCOM to increase your sanctioned load, sometimes needed before installing a larger solar system.

M

MC4 connector

The standard weatherproof, locking connector used to join solar DC cables and modules.

MNRE(Ministry of New and Renewable Energy)

The Government of India ministry responsible for renewable energy, including rooftop solar schemes.

Monocrystalline

Solar cells cut from a single silicon crystal. Higher efficiency and a uniform dark look; the standard for modern rooftops.

MPERC(MP Electricity Regulatory Commission)

The regulator that sets electricity tariffs and net-metering regulations in Madhya Pradesh.

MPPT(Maximum power point tracking)

The inverter function that continuously adjusts to extract the most power from the array as light and temperature change.

N

Net metering

A billing arrangement in which exported solar units are offset against imported units, so you pay only for the net.Learn more

O

Off-grid system

A solar system with batteries and no grid connection.Learn more

On-grid system(Grid-tied)

A solar system connected to the utility grid without batteries, using net metering. The most cost-effective type for most homes.Learn more

P

PERC(Passivated Emitter and Rear Cell)

A mono cell design that reflects unused light back through the cell, raising efficiency. The mainstream technology of the last decade.

Performance ratio (PR)

Actual output divided by theoretical output from the sunlight received. Well-designed rooftop systems achieve about 0.75–0.82.

PM Surya Ghar: Muft Bijli Yojana

The central government scheme (launched 2024) providing subsidy for residential rooftop solar — up to ₹78,000 per home and ₹18,000 per kW for housing societies.Learn more

Polycrystalline

Solar cells made from multiple silicon crystals. Cheaper but less efficient; largely replaced by mono.

S

Sanctioned load

The electrical load (kW) approved for your connection by the DISCOM. Net-metered solar capacity is generally linked to it.Learn more

SPD(Surge protection device)

A device in the DCDB/ACDB that diverts voltage surges (e.g. from lightning) away from the inverter.

String

A group of solar modules connected in series to reach the inverter's operating voltage.

String inverter

A central inverter that handles one or more strings of modules. The standard choice for Indian rooftops.Learn more

T

Temperature coefficient

How much a module's power drops per °C rise in cell temperature, typically -0.30% to -0.40%/°C. Lower is better in hot climates.

Tilt angle

The angle of the modules from horizontal. Around 15–23° suits Indore.Learn more

TOPCon(Tunnel Oxide Passivated Contact)

An n-type cell technology with higher efficiency, lower degradation and better heat tolerance than PERC.Learn more

Y

Yield (specific)

Annual energy produced per kWp installed. About 1,400–1,550 kWh/kWp in Indore depending on site and losses.Learn more