Ground Mount Solar Glossary
Plain-language definitions for common solar terminology. Bookmark this page for reference as you research ground mount solar.
A
- AC (Alternating Current)
- The type of electricity used in homes and delivered by the grid. Solar panels produce DC power, which inverters convert to AC for home use. AC power alternates direction 60 times per second (60 Hz) in North America.
- Array
- A group of solar panels wired together. A ground mount array is the complete set of panels installed on your property. Arrays can be configured in single rows, multiple rows, or other layouts depending on available space.
- Azimuth
- The compass direction your solar panels face, measured in degrees. True south is 180° azimuth and produces maximum output for ground mounts in the Northern Hemisphere. East is 90°, west is 270°. Deviation from south reduces production but may be acceptable depending on your goals.
B
- Ballasted Mount
- A ground mount foundation that uses weight (concrete blocks, gravel) to hold the system in place rather than penetrating the ground. Useful when you can't or don't want to dig—such as on leased land, rocky sites, or areas with environmental restrictions. Requires flat terrain and more material than other foundation types.
- Bidirectional Meter
- An electric meter that measures power flowing in both directions: electricity you consume from the grid and electricity your solar system sends back. Also called a net meter. Required for net metering programs. Your utility typically installs this as part of interconnection.
D
- DC (Direct Current)
- The type of electricity solar panels produce. Current flows in one direction only. Must be converted to AC by an inverter before use in your home or export to the grid. Battery storage systems also use DC power.
- Degradation
- The gradual decline in solar panel output over time. Modern panels typically degrade 0.3-0.5% per year. After 25 years, a panel might produce 85-90% of its original output. Manufacturers guarantee minimum output levels in their warranties.
- Driven Post
- A steel post hammered directly into the ground using specialized machinery. The cheapest foundation option for ground mount solar. Requires suitable soil conditions—won't work in rocky ground or areas with high water tables. Installation is fast when conditions are right.
G
- Ground Screw
- A helical pile foundation that screws into the ground like a large screw. Also called a helical anchor. No concrete required. Works in most soil types except solid rock. Can be removed later with minimal site impact. Popular for residential ground mount installations.
I
- Interconnection
- The process of connecting your solar system to the utility grid. Requires an agreement with your utility, submission of system specifications, engineering review, meter installation, and final approval (permission to operate). Timelines vary from 2 weeks to 3+ months depending on the utility.
- Inverter
- The device that converts DC power from solar panels into AC power for home use. Also manages power flow, monitors system performance, and ensures safe disconnection during grid outages. String inverters handle power from multiple panels; microinverters are installed on each panel individually.
K
- Kilowatt (kW)
- A unit of power equal to 1,000 watts. Solar system size is measured in kilowatts—a 10kW system has panels with a combined rated output of 10,000 watts under standard test conditions. Residential ground mount systems typically range from 6-20 kW.
- Kilowatt-hour (kWh)
- A unit of energy. One kilowatt-hour is the energy used by a 1,000-watt device running for one hour. Your electric bill is measured in kWh. A 10kW solar system in a sunny location might produce 12,000-15,000 kWh per year.
M
- Microinverter
- A small inverter installed on each individual solar panel. Converts DC to AC right at the panel. Advantages: panel-level optimization, better performance in partial shade, easier system expansion. Disadvantages: higher upfront cost, more components that could fail. Compare to string inverters.
- Module
- Another term for a solar panel. A module is a complete unit of interconnected solar cells with protective glass, frame, and wiring. Modern residential modules typically produce 350-450 watts each and measure about 6.5 feet by 3.5 feet.
N
- Net Metering
- A billing arrangement where your utility credits you for excess electricity your solar system sends to the grid. When your panels produce more than you use, the meter runs backward. You draw from those credits when you need grid power (at night, cloudy days). Policies vary by utility and state—some offer full retail credit, others less.
O
- Orientation
- The direction your solar panels face. South-facing panels produce the most energy in the Northern Hemisphere. East-facing panels produce more morning power; west-facing panels produce more afternoon power. Ground mount systems can be oriented optimally regardless of how your house is positioned.
P
- Permission to Operate (PTO)
- Final utility approval to turn on your solar system and connect it to the grid. Issued after installation is complete, inspections pass, and interconnection requirements are met. You cannot legally operate your system until receiving PTO. Timeline varies by utility.
- Photovoltaic (PV)
- Technology that converts sunlight directly into electricity. Solar panels are photovoltaic devices. The term comes from "photo" (light) and "voltaic" (electricity). PV is distinct from solar thermal, which uses sunlight for heat.
R
- Racking
- The metal framework that holds solar panels in place. Ground mount racking includes the posts or foundations, cross-beams, rails, and panel clamps. Racking determines the tilt angle and can be fixed or adjustable. Quality racking is engineered to withstand local wind and snow loads.
- Rapid Shutdown
- A safety requirement (NEC 2017+) that solar systems must be able to quickly reduce voltage to safe levels when emergency responders or maintenance workers need access. Implemented through module-level electronics or other approved methods. Your system will include rapid shutdown compliance.
S
- Setback
- The required distance between a structure and property lines. Ground mount solar systems are typically classified as accessory structures and must meet local setback requirements. Common setbacks range from 5-25 feet depending on the zone and which property line. Check local zoning codes.
- Single-Axis Tracker
- A ground mount system that rotates east-to-west throughout the day to follow the sun's path. Increases energy production by 15-25% compared to fixed systems but costs 20-30% more and has moving parts. More common in commercial installations than residential.
- String Inverter
- A central inverter that handles power from a "string" of multiple panels wired in series. One string inverter serves the entire array or a large section. Advantages: lower cost, fewer components, easier maintenance access. Disadvantages: if one panel is shaded, it affects the whole string. Compare to microinverters.
T
- Tilt Angle
- The angle of solar panels relative to horizontal ground, measured in degrees. Optimal tilt roughly equals your latitude for year-round production. Steeper tilts favor winter production; shallower tilts favor summer. Ground mounts can be set to any tilt angle; rooftop systems are limited by roof pitch.
- Trenching
- Digging a trench to bury electrical conduit between the solar array and your home's electrical panel. Required for all ground mount installations. Trenching depth (typically 18-24 inches) and conduit specifications are determined by electrical code. Longer runs increase project cost.
U
- Utility Interconnection Agreement
- A contract between you and your utility that establishes the terms for connecting your solar system to the grid. Covers technical requirements, metering, safety standards, and compensation for excess power. Required before your system can operate legally.
W
- Watt
- The basic unit of electrical power. Solar panel output is rated in watts under standard test conditions. A 400-watt panel produces 400 watts of power at peak performance. 1,000 watts = 1 kilowatt (kW). System cost is often quoted per watt.
Understanding Solar Measurements
Solar terminology can be confusing because the industry uses multiple units that sound similar. Here's the key distinction:
- Kilowatts (kW) measure power capacity—how much your system can produce at any given moment. A 10kW system has 10 kilowatts of rated capacity.
- Kilowatt-hours (kWh) measure energy over time—what you actually produce or consume. Your electric bill shows kWh usage.
Think of it like a car: kW is like horsepower (capability), while kWh is like miles driven (actual usage over time). A 10kW system running at full capacity for one hour produces 10 kWh of energy.
Common Abbreviations
| Abbreviation | Meaning |
|---|---|
| AC | Alternating Current |
| DC | Direct Current |
| kW | Kilowatt (1,000 watts) |
| kWh | Kilowatt-hour |
| NEC | National Electrical Code |
| PTO | Permission to Operate |
| PV | Photovoltaic |
| W | Watt |