Solar Terms Unlocked

Your go-to guide for essential solar terminology.

A

Accelerated Depreciation

Accounting methodology under which certain fixed assets can be depreciated at higher rates in the early years of their asset lives. This directly translates to tax savings.

Alternating Current (AC)

Electric current that periodically reverses its direction and magnitude. In India, it operates at 50 cycles per second.

Array (Solar Array)

A collection of solar modules arranged in strings to form a complete PV system.

B

Backtracking

A tracking mechanism to minimize shading between panels in solar tracking systems.

Bi-directional Energy Meter (Net Meters)

A meter that measures both imported and exported electricity. It moves forward when power is drawn from the grid and backward when power is fed into the grid.

Battery Bank

A group of batteries connected to store energy for later use, commonly used in off-grid systems.

C

CAPEX

Capital expenditure where users pay the total cost of a solar system upfront and take responsibility for its operation and maintenance.

Capacity Utilization Factor (CUF)

The ratio of actual energy generated to the maximum possible energy output in a given time frame.

Capital Subsidy

A government grant to reduce the upfront cost of installing solar systems, provided by MNRE through state nodal agencies.

Central Inverters

Large inverters used in utility-scale systems to convert DC electricity to AC from multiple solar strings.

Corrective Maintenance

Repairs or maintenance activities performed to restore equipment to its operational state after failure.

D

Data Logger

A device that records performance and operational data for monitoring and analysis.

Direct Current (DC)

Electric current that flows in one direction without changing polarity or magnitude.

DERC (Delhi Electricity Regulatory Commission)

The regulatory body responsible for electricity-related policies in Delhi.

E

Energy Efficiency Ratio (EER)

A measure of how efficiently energy is utilized in a system.

Energy Yield

The total amount of electricity generated by a solar PV system over a specific period.

F

Feed-in Tariff (FiT)

A payment model that compensates solar system owners for the electricity they generate and feed into the grid.

Fixed Tilt

A non-adjustable angle at which solar panels are installed to optimize power generation year-round.

G

Grid Parity

When the cost of solar electricity matches or is lower than the cost of grid electricity.

Gross Metering

A metering mechanism that records the total solar energy generated and fed into the grid.

Guarantees

Manufacturer assurances for performance or replacement of solar equipment within a specified period.

I

Insolation

The amount of solar radiation received per square meter, measured in kWh/m².

Irradiation

The solar power per unit area at a specific time, typically expressed in W/m².

L

LCOE (Levelized Cost of Energy)

A metric for comparing the cost of electricity generation across different energy sources by considering lifetime costs.

LT Line (Low Tension Line)

Electricity supply lines operating at 415V for three-phase or 230V for single-phase systems.

M

Micro Inverters

Small inverters installed on individual panels to convert DC electricity to AC.

MNRE

The Ministry of New and Renewable Energy, Government of India, responsible for promoting solar and other renewable energies.

MPPT (Maximum Power Point Tracking)

A technology to optimize power output by ensuring panels operate at their peak efficiency.

N

Net Metering

A billing mechanism that credits solar energy producers for excess power fed into the grid.

Nodal Agency

State-level agencies responsible for implementing solar policies and distributing subsidies.

O

Off-grid Solar

A standalone solar system supported by a battery bank, not connected to the utility grid.

On-grid Solar

A solar system directly connected to the grid, relying on it for backup power.

P

PPA (Power Purchase Agreement)

A contract between a power producer and purchaser outlining terms for power sale and delivery.

Performance Ratio (PR)

An efficiency metric indicating how effectively a solar PV system converts sunlight into usable electricity.

Preventive Maintenance

Scheduled maintenance to reduce the risk of equipment failure.

R

RESCO Model

A solar financing model where a third party owns and maintains the system while the user pays only for the generated electricity.

Return on Investment (ROI)

A financial measure to evaluate the profitability of a solar system investment.

S

Seasonal Tilt

Adjustable panel angles optimized for different seasons to maximize energy production.

Solar Hybrid System

A solar system integrated with another power source like a diesel generator or the grid for enhanced reliability.

String Inverter

An inverter connected to multiple panel strings to convert their DC power into AC.

T

Tracking System

A mechanism that adjusts panel angles to follow the sun's path, increasing power output.

Three-phase Power

A power supply system with three active wires delivering 415V across phases.

U

kWh (Kilowatt-hour)

A unit of energy equal to using 1,000 watts for one hour.

kWp (Kilowatt-peak)

The maximum power output of a solar system under standard testing conditions.

W

Warranty

A manufacturer's commitment to repair or replace equipment if defects arise within the covered period.