Solar glossary: 20 terms every buyer should know
Short, accurate definitions in plain English.
Net metering
A billing arrangement where a bi-directional meter records electricity you import from and export to the grid; exports are credited against imports.
PM Surya Ghar Muft Bijli Yojana
India's central scheme giving households subsidy of ₹30,000/kW up to 2 kW and ₹18,000 for the third kW (max ₹78,000) for rooftop solar.
kWp / kW
Kilowatt-peak: a solar system's rated capacity under standard test conditions. A 3 kW system has about 6 modules of 540 Wp.
DCR modules
Domestic Content Requirement modules made with Indian cells; mandatory for PM Surya Ghar subsidy.
ALMM
Approved List of Models and Manufacturers: MNRE's list of eligible solar modules for government-linked projects.
On-grid inverter
Converts DC power from panels into AC and synchronises with the grid; switches off during outages for safety.
Hybrid inverter
Inverter that works with batteries and the grid, enabling backup during power cuts.
Off-grid system
Solar plus batteries without a grid connection; no net metering or subsidy.
Anti-islanding
Safety feature that shuts down grid-tied solar during a grid outage to protect line workers.
Payback period
Net system cost divided by yearly savings; 3.5–5 years is typical for homes in Kerala.
Performance warranty
Manufacturer guarantee that panels deliver a minimum output (e.g. 80–87%) after 25 years.
Degradation
Gradual decline in panel output, typically 0.4–0.7% per year.
RESCO / OPEX model
A developer owns and maintains the solar plant; you pay a per-unit tariff with no upfront cost.
CAPEX model
You buy the solar system outright and own all savings.
Sanctioned load
The maximum load (kW) approved by KSEB/TNPDCL for your connection; limits the solar capacity you can connect.
KSEB
Kerala State Electricity Board, the utility for Thiruvananthapuram and Kollam districts.
TNPDCL
Tamil Nadu Power Distribution Corporation (formerly TANGEDCO), the utility for Kanyakumari district.
PM-KUSUM
Central scheme supporting solar pumps and farm solarisation for farmers.
Virtual / group net metering
Allows one solar plant to credit multiple meters, e.g. in apartments, where permitted by regulation.
Solar Health Check
The Solar Daily's annual maintenance plan covering cleaning, monitoring, fault detection and warranty support.