Approved List of Models and Manufacturers — MNRE's mandatory approval registry. All solar PV modules and inverters used in government schemes, subsidies, open-access projects, and RPO compliance must be sourced from ALMM-listed manufacturers.

A PV module that generates electricity from both the front and rear surfaces by capturing reflected (albedo) light from the ground. Rear-side gain adds 5–25% energy over an equivalent monofacial module.

Balance of System — all solar installation components other than the PV modules: inverters, mounting structures, DC and AC wiring, junction boxes, earthing, protection devices, and monitoring equipment.

Capacity Utilisation Factor — the ratio of actual annual energy output to the maximum possible output at full rated capacity for all 8,760 hours. India's standard KPI for grid-scale solar, also called PLF (Plant Load Factor).

Distribution Company — a state-regulated electricity distribution utility that owns the local grid, bills retail consumers, and is the counterparty for net-metering agreements, open-access, and subsidy disbursement in India.

Engineering, Procurement and Construction — a project delivery model where a single contractor handles complete solar installation including system design, equipment procurement, civil work, commissioning, and handover under a fixed-price contract.

The ratio of a solar cell's maximum power output to the product of its open-circuit voltage and short-circuit current. A key datasheet quality metric — typical commercial values: 0.78–0.84.

Global Horizontal Irradiance — the total solar radiation received per unit area on a horizontal surface, combining direct beam, diffuse sky, and reflected radiation. India's GHI ranges 4.0–6.5 kWh/m²/day across states.

Heterojunction Technology — a solar cell combining crystalline silicon with amorphous silicon thin-film layers on both surfaces. Offers the best temperature coefficient of any commercial silicon technology (−0.24%/°C) and efficiencies above 23%.

Maximum Power Point Tracking — a control algorithm in solar inverters that continuously finds the voltage-current operating point at which a PV array delivers maximum power under any given irradiance and temperature.

A grid-connected solar billing arrangement where surplus electricity exported to the grid is credited against the consumer's import bill — effectively running the meter backwards. India's primary residential solar incentive mechanism.

Nominal Operating Cell Temperature — the equilibrium cell temperature at 800 W/m² irradiance, 20°C ambient, and 1 m/s wind. More representative of field conditions than STC's 25°C cell temperature assumption.

Passivated Emitter and Rear Cell — a monocrystalline silicon solar cell technology with a dielectric passivation layer on the rear surface that reflects unabsorbed photons back into the cell, boosting efficiency 0.5–1% absolute over standard BSF cells.

The ratio of actual energy yield to the theoretically expected yield based on in-plane irradiation and nameplate capacity — the internationally accepted O&M KPI for solar plants. Typical range in India: 0.70–0.85.

Renewable Energy Certificate — a market-based instrument issued by POSOCO representing 1 MWh of renewable electricity. Obligated entities (DISCOMs, open-access consumers) buy RECs to meet their Renewable Purchase Obligations.

Renewable Purchase Obligation — a mandatory quota set by CERC/SERCs requiring DISCOMs, open-access consumers, and captive users to source a minimum percentage of electricity from renewable sources. The primary regulatory demand driver for Indian solar.

Standard Test Conditions — the standardised lab conditions used to measure and compare PV module performance: 1000 W/m² irradiance, 25°C cell temperature, and AM 1.5G spectrum. All module datasheets quote ratings at STC.

The angle of PV modules from the horizontal plane. Typically set to the site's latitude for maximum annual yield — deviations of ±5° cost less than 1% energy. Steeper tilts improve monsoon rain self-cleaning in dusty regions.

Tunnel Oxide Passivated Contact — an advanced silicon solar cell technology with a thin tunnel oxide and polysilicon layer on both surfaces, minimising recombination losses and enabling mass-production efficiencies of 22–24%.