Glossary
Solar Glossary
Solar terminology explained in plain English. No jargon, no confusion—just clear definitions.
A
Array
A group of solar panels wired together as a single unit. A typical residential ground mount system is one array, though larger properties may have multiple arrays.
Azimuth
The compass direction your panels face, measured in degrees from north. In Texas, panels typically face due south (180°) for maximum production, though southeast or southwest can work well too.
B
Bidirectional Meter
A utility meter that measures electricity flowing both into your home from the grid and out to the grid from your solar system. Required for net metering and solar buyback programs.
C
Capacity Factor
The ratio of actual energy produced to theoretical maximum output. Texas solar typically achieves 18-22% capacity factor—panels produce about 20% of their rated capacity on average due to night, clouds, and seasonal variation.
D
DC/AC
Direct Current (DC) is what solar panels produce. Alternating Current (AC) is what your home uses. An inverter converts DC to AC. System size is typically quoted in DC watts.
Degradation
The gradual decrease in solar panel output over time. Modern panels degrade about 0.3-0.5% per year, meaning a panel producing 400W new will still produce ~350W after 25 years.
E
ERCOT
The Electric Reliability Council of Texas—the organization managing the Texas electrical grid. Most of Texas is on the ERCOT grid, which operates independently from the rest of the U.S. This affects how solar interconnection works.
G
Grid-Tied
A solar system connected to the utility grid. Excess power goes to the grid for credits; you draw from the grid when solar isn't enough. Most residential systems are grid-tied.
Ground Mount
A solar installation mounted on a freestanding structure on the ground rather than on a roof. Uses steel racking and foundations (concrete or helical piles) to hold panels at optimal angle.
H
Helical Pile
A steel foundation anchor with helical (screw-like) plates that's mechanically driven into the ground. Ideal for rocky Hill Country soil where traditional excavation is difficult. Creates a stable foundation without concrete.
I
Interconnection
The process of connecting your solar system to the utility grid. Involves paperwork, inspections, and meter installation. In Texas, this typically takes 2-4 weeks after permits are approved.
Inverter
The device that converts DC electricity from solar panels into AC electricity your home can use. The "brain" of your solar system that also monitors production and communicates with the grid.
ITC (Investment Tax Credit)
The federal tax credit for solar installations—currently 30% of total system cost. This is a dollar-for-dollar reduction in your federal taxes owed, not a rebate. Available through 2032.
K
kW (Kilowatt)
A measure of power—the rate at which energy is produced or consumed. A 10kW solar system can produce up to 10 kilowatts of power under ideal conditions. System size is quoted in kW.
kWh (Kilowatt-hour)
A measure of energy—power over time. Your electric bill is measured in kWh. A 10kW system producing power for 5 hours generates 50 kWh. Annual production is the key metric for savings calculations.
M
Microinverter
A small inverter attached to each individual panel, converting DC to AC at the panel level. Better for shaded conditions but more expensive than string inverters. Each panel operates independently.
Module
Another word for a solar panel. A single photovoltaic unit that converts sunlight to electricity. Modern residential modules are typically 400-450 watts and measure about 3.5' x 6.5'.
N
Net Metering
A billing arrangement where excess solar power sent to the grid earns credits against power you buy later. Traditional net metering (1:1 credit) is rare in Texas; most utilities use "net billing" with lower export rates.
O
Off-Grid
A solar system completely disconnected from the utility grid. Requires battery storage to provide power when panels aren't producing. More expensive but provides complete energy independence.
P
Peak Sun Hours
The equivalent hours per day of full-strength sunlight (1,000 W/m²). Texas averages 4.5-5.5 peak sun hours daily depending on location. Used to estimate annual production: system size × peak sun hours × 365 = annual kWh.
PTO (Permission to Operate)
Final approval from your utility to turn on your solar system and connect to the grid. Issued after all inspections pass and interconnection is complete. You can't legally operate grid-tied solar without PTO.
R
Racking
The metal framework that holds solar panels in place. Ground mount racking is typically galvanized steel designed for wind loads and adjustable tilt angles. A significant cost factor for ground mount systems.
S
Self-Consumption
Using your solar power directly rather than sending it to the grid. With Texas utilities offering low export credits, maximizing self-consumption improves economics. Running high-draw appliances during sunny hours increases self-consumption.
Solar Buyback
Texas term for plans where Retail Electric Providers (REPs) purchase your excess solar production. Rates vary widely (3¢-15¢/kWh) between providers. Only available in deregulated areas like DFW and Houston.
String Inverter
A central inverter that converts DC power from a "string" of panels wired together. Most common for ground mount systems. Efficient and cost-effective when shading isn't an issue.
T
Tax Credit vs Rebate
A tax credit reduces your tax bill dollar-for-dollar (you must owe taxes to benefit). A rebate is cash back regardless of tax situation. The 30% federal solar incentive is a tax credit, not a rebate.
Tier 1 Panels
Solar panels from manufacturers ranked in the top tier by Bloomberg New Energy Finance. Indicates financial stability and bankability, not necessarily panel quality—though Tier 1 makers generally produce reliable panels.
Tilt Angle
The angle at which panels are mounted relative to horizontal. In Texas, optimal tilt is roughly equal to your latitude (26-36°). Ground mounts can achieve optimal tilt; rooftops are limited by roof pitch.
V
Value of Solar (VoS)
Austin Energy's unique program that credits all solar production (not just excess) at a set rate—currently 9.91¢/kWh. A second meter measures production. Different from net metering used elsewhere.
Key Concepts for Texas Solar
kW vs kWh: The Difference That Matters
kW (kilowatts) = power capacity. Like horsepower in a car.
kWh (kilowatt-hours) = energy produced. Like miles driven.
Your system is sized in kW. Your savings are measured in kWh. An 8kW system in Texas produces roughly 12,000 kWh/year.
Net Metering vs Solar Buyback
Net metering = 1:1 credit for excess power. Rare in Texas.
Solar buyback = REPs buy excess at variable rates. Common in deregulated areas.
Austin Energy's Value of Solar is unique—credits all production, not just excess.
String Inverter vs Microinverter
String inverter = one central inverter for all panels. Lower cost, works great for unshaded ground mount.
Microinverters = one per panel. Better for shade, higher cost.
Most ground mount systems use string inverters since shading is typically minimal.
Tax Credit vs Rebate
Tax credit = reduces taxes you owe. Requires tax liability.
Rebate = cash back. Doesn't require tax liability.
The 30% federal incentive is a tax credit. No state rebates currently available in Texas.
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