Solar Glossary
Solar jargon translated into plain English. No industry buzzwords, just clear definitions for the terms you'll actually encounter.
A
AC (Alternating Current)
The type of electricity your home uses. Solar panels produce DC power, which an inverter converts to AC before it flows into your house. All your appliances, outlets, and the grid run on AC.
Azimuth
The compass direction your panels face, measured in degrees from north. In Texas, panels should ideally face 180° (true south) for maximum production. East-facing (90°) or west-facing (270°) panels produce 10-15% less power.
B
Balance of System (BOS)
Everything in a solar installation besides the panels themselves: racking, wiring, inverter, disconnects, monitoring, and labor. BOS typically accounts for 40-50% of total system cost.
C
Capacity Factor
The percentage of a system's rated capacity that it actually produces over time. Texas residential solar typically achieves 18-22% capacity factor, meaning a 10kW system produces an average of 1.8-2.2kW around the clock (accounting for night, clouds, and seasons).
D
DC (Direct Current)
The type of electricity solar panels produce. Electrons flow in one direction. Must be converted to AC before use in your home or export to the grid. Battery systems also store power as DC.
Degradation
The gradual decline in panel output over time. Modern panels degrade about 0.5% per year. A panel rated at 400W will produce about 340W after 25 years. This is normal and factored into production estimates.
E
ERCOT
Electric Reliability Council of Texas. The organization that manages the Texas electric grid and oversees interconnection of distributed generation like residential solar. Most of Texas operates on the ERCOT grid.
G
Ground Mount
A solar installation where panels are mounted on a freestanding structure anchored to the ground, rather than on a roof. Requires foundation work (posts or piers) and dedicated land, but offers optimal panel positioning.
I
Interconnection
The process and agreement that allows your solar system to connect to the utility grid. Includes application, approval, and often a new or reconfigured meter. Required before you can legally operate a grid-tied system.
Inverter
The device that converts DC power from panels to AC power for your home. String inverters are most common for ground mount; microinverters mount on each panel. Inverters also handle grid synchronization and safety disconnection.
Irradiance
The amount of solar energy hitting a surface, measured in watts per square meter (W/m²). Peak irradiance is about 1,000 W/m² on a clear day. Texas gets 4.5-5.5 peak sun hours per day on average.
K
kW (Kilowatt)
A unit of power equal to 1,000 watts. System size is measured in kW. A 10kW system can produce up to 10,000 watts at peak output. Typical Texas homes need 8-12kW of solar to offset their usage.
kWh (Kilowatt-hour)
A unit of energy equal to using 1,000 watts for one hour. This is what you're billed for on your electric bill. A 10kW system in Texas produces roughly 14,000-16,000 kWh per year.
M
Microinverter
A small inverter that mounts on or near each individual panel, converting DC to AC at the source. More expensive than string inverters but offers panel-level optimization and monitoring. Easier troubleshooting if one panel underperforms.
Module
Another name for a solar panel. The terms are used interchangeably. A module contains multiple solar cells wired together and encased in glass and a protective frame.
N
Net Metering
A billing arrangement where excess solar power sent to the grid is credited at the same rate you pay for power. Texas doesn't have statewide net metering, but some utilities and retail providers offer it or similar programs.
P
Peak Sun Hours
A way to measure solar resource. One peak sun hour equals one hour of 1,000 W/m² irradiance. Texas averages 4.5-5.5 peak sun hours daily. More peak sun hours means more solar production.
Permission to Operate (PTO)
Official approval from your utility to turn on your solar system and begin grid interconnection. Issued after all inspections pass and interconnection paperwork is complete. Never energize a system before receiving PTO.
Photovoltaic (PV)
The technology that converts sunlight directly into electricity using semiconductor materials. Solar panels are photovoltaic devices. The word comes from 'photo' (light) and 'voltaic' (electricity).
R
Racking
The mounting structure that holds solar panels in place. For ground mount, this includes posts or piers driven into the ground, horizontal rails, and panel clamps. Made from galvanized steel or aluminum for durability.
Rapid Shutdown
A safety feature required by electrical code that quickly reduces panel voltage in emergencies. Allows firefighters and first responders to safely work near a solar system. Modern inverters include this automatically.
REP (Retail Electric Provider)
In deregulated Texas markets, the company you buy electricity from. Your REP handles billing and may offer solar buyback programs. Different from the TDU, which handles the physical infrastructure.
S
Solar Cell
The basic unit that converts light to electricity. Made of silicon semiconductors. A typical solar panel contains 60-72 cells wired together. Each cell produces about 0.5 volts.
String Inverter
A central inverter that handles power from multiple panels wired together in series (a 'string'). Cost-effective and reliable for ground mount installations. If one panel is shaded, it can affect the whole string's output.
T
TDU (Transmission and Distribution Utility)
The company that owns and maintains the power lines in your area. In Texas, examples include Oncor, CenterPoint, and AEP. They handle the physical interconnection of your solar system to the grid.
Tilt Angle
The angle of your panels relative to horizontal ground, measured in degrees. For fixed ground mount in Texas, optimal tilt is typically 25-35°, roughly equal to your latitude. Steeper tilt favors winter production; shallower favors summer.
Tier 1 Manufacturer
A designation from Bloomberg New Energy Finance for financially stable solar panel manufacturers with vertically integrated production and strong track records. Includes companies like Qcells, Canadian Solar, JA Solar, and Jinko. Generally indicates reliable equipment.
Tracker
A mounting system that moves panels to follow the sun throughout the day. Single-axis trackers tilt east-to-west; dual-axis trackers also adjust tilt angle seasonally. Increases production 15-30% but adds cost and complexity. Rare for residential ground mount.
U
Utility-Scale Solar
Large solar installations (typically 1 MW or larger) that sell power to utilities. Different from residential and commercial solar. Texas has significant utility-scale solar development, especially in West Texas.
W
Watt
The basic unit of power. One watt equals one joule per second. Solar panels are rated by their watt output under standard test conditions. A 400W panel produces 400 watts at peak performance.
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