Solar Energy Glossary for Georgia Homeowners
Georgia homeowners evaluating photovoltaic systems encounter a dense technical vocabulary that spans electrical engineering, utility regulation, and state-specific incentive programs. This glossary defines the terms most relevant to residential solar decisions in Georgia, from equipment specifications to interconnection rules enforced by the Georgia Public Service Commission. Understanding these terms is foundational to reading installer proposals, interpreting utility agreements, and navigating the regulatory context for Georgia solar energy systems. The definitions below are organized by topic area and cross-referenced to the processes and frameworks that govern Georgia installations.
Definition and scope
A solar energy glossary for Georgia homeowners is a structured reference that defines the technical, financial, regulatory, and operational vocabulary used across the photovoltaic (PV) system lifecycle — from site assessment through end-of-life equipment disposal. The terms covered apply specifically to grid-tied and off-grid residential systems installed in Georgia and governed by state and local authority having jurisdiction (AHJ) requirements.
Scope and coverage: This glossary covers terminology relevant to residential solar installations in the state of Georgia, including rules administered by the Georgia Public Service Commission (PSC), Georgia Power's interconnection tariffs, and local building departments operating under the Georgia State Minimum Standard Codes. It does not address commercial-scale or utility-scale projects subject to Federal Energy Regulatory Commission (FERC) jurisdiction, nor does it cover solar installations in other states. Federal tax credit terminology (such as the Investment Tax Credit under 26 U.S.C. § 48(a)) is included where it intersects with Georgia homeowner decisions, but federal regulatory filings fall outside this page's coverage. Agricultural solar contexts are not covered here — see Agricultural Solar Energy Systems in Georgia for that scope.
How it works
Solar terminology functions as a classification and communication system across three distinct domains: technical, regulatory, and financial. Each domain carries its own vocabulary set, and a given term may carry different meanings depending on which domain applies.
Technical terms
Photovoltaic (PV) cell: The fundamental electricity-generating unit in a solar panel. A silicon-based PV cell converts photons into direct current (DC) electricity through the photovoltaic effect. Standard residential panels in Georgia typically consist of 60 to 72 individual cells per module.
Module vs. panel vs. array: These three terms are not interchangeable. A module is a single factory-assembled unit (typically 250–400 watts nameplate capacity). A panel is an informal term often used synonymously with module. An array is the complete collection of modules installed at a site.
DC (direct current) vs. AC (alternating current): PV modules produce DC electricity. Georgia homes and the utility grid operate on AC at 120/240 volts, 60 Hz. An inverter performs the DC-to-AC conversion. This distinction matters for understanding system losses, NEC wiring requirements, and inverter sizing.
Inverter types — string vs. microinverter vs. power optimizer:
- String inverter: Connects a series ("string") of modules to a single inverter. Lowest cost; performance limited by the weakest module in the string. Governed by NEC Article 690.
- Microinverter: One inverter per module. Eliminates string-level mismatch losses; cost per watt is higher. Common in partially shaded Georgia rooftops.
- Power optimizer: Module-level DC conditioning device paired with a central string inverter. Intermediate cost and performance position between string and microinverter architectures.
Nameplate capacity (kW DC vs. kW AC): Nameplate capacity is the rated output of a module or array under Standard Test Conditions (STC: 1,000 W/m², 25°C cell temperature, AM 1.5 spectrum per IEC 61215). Real-world Georgia output is lower due to heat (Georgia summer cell temperatures routinely exceed 45°C), soiling, and shading. The ratio of AC system output to DC nameplate is the DC-to-AC derate factor, typically 0.75–0.85 for residential systems per NREL's PVWatts Calculator.
Tilt angle and azimuth: Tilt is the angle of the panel surface relative to horizontal; azimuth is the compass orientation. In Georgia (latitude approximately 30°–35° N), south-facing arrays at a tilt matching site latitude maximize annual production, though roof pitch constraints frequently modify this ideal.
Temperature coefficient: The rate at which a module's power output changes with cell temperature, expressed as % per °C. A typical crystalline silicon module has a temperature coefficient of −0.35% to −0.45%/°C. Georgia's high summer ambient temperatures make this specification directly relevant to production estimates — a 10°C rise above STC reduces output by 3.5–4.5%.
Regulatory and interconnection terms
Authority Having Jurisdiction (AHJ): The organization, office, or individual responsible for enforcing the requirements of a code or standard, as defined by the National Fire Protection Association (NFPA). In Georgia residential solar, the AHJ is typically the county or municipal building department.
Interconnection agreement: A contract between a homeowner and their electric utility that establishes the technical and legal conditions for connecting a PV system to the grid. Georgia Power's interconnection process is governed by its Commission-approved tariffs on file with the Georgia PSC. Georgia Electric Membership Corporations (EMCs) operate under separate interconnection rules; see Georgia Electric Membership Corporation Solar Policies for EMC-specific terms.
Net metering: A billing arrangement in which excess electricity exported to the grid offsets a customer's consumption charges. Georgia's net metering landscape is defined by the Georgia PSC and individual utility tariffs. The specifics of Georgia Power's current avoided-cost buyback rate are detailed in Georgia Net Metering Policy Explained.
Avoided cost rate: The rate at which a utility compensates a customer for excess solar generation, set to reflect the utility's cost of producing or procuring equivalent power. Under Georgia PSC rules, this rate is typically lower than the retail electricity rate.
Utility interconnection study: A technical review conducted by the utility to assess whether a proposed PV system will cause power quality, safety, or capacity issues on the distribution circuit. Required for systems above certain capacity thresholds. The full process is described in Georgia Utility Interconnection Requirements.
Parallel operation: Operating a customer-owned generator (including PV) simultaneously with the utility grid. NEC Article 705 and IEEE Standard 1547-2018 govern the technical requirements for parallel operation, including anti-islanding protection.
Anti-islanding protection: A required inverter function that automatically disconnects the PV system from the grid during a utility outage, preventing energization of de-energized utility lines — a critical safety requirement protecting utility workers. IEEE 1547-2018 mandates anti-islanding performance parameters.
Permission to Operate (PTO): Written authorization from the utility allowing a homeowner to energize and operate a grid-tied PV system. PTO is issued after the utility reviews the installation for compliance with interconnection requirements and after the AHJ issues a final inspection approval.
Financial and incentive terms
Investment Tax Credit (ITC): A federal income tax credit under 26 U.S.C. § 48(a), as amended by the Inflation Reduction Act of 2022, equal to 30% of eligible PV system costs for systems placed in service through 2032 (U.S. Department of Energy, DSIRE). Georgia homeowners claim this credit on IRS Form 5695. See Federal Solar Tax Credit Application for Georgia Residents for filing specifics.
Property Assessed Clean Energy (PACE): A financing mechanism allowing repayment of energy improvement loans through property tax assessments. Georgia enacted PACE enabling legislation (O.C.G.A. § 36-62-1 et seq.), but program availability varies by county.
Power Purchase Agreement (PPA): A contract in which a third party owns and operates a PV system on a homeowner's property and sells the generated electricity to the homeowner at an agreed rate. PPAs transfer equipment ownership and associated tax credits to the developer, not the homeowner. Detailed in Power Purchase Agreements in Georgia.
Solar lease: An arrangement in which the homeowner pays a fixed monthly fee to use a third-party-owned PV system, regardless of production levels. Contrasted with a PPA in Solar Leasing vs. Purchasing in Georgia: under a lease, payment is fixed; under a PPA, payment is per kilowatt-hour.
Levelized Cost of Energy (LCOE): The total lifecycle cost of a PV system divided by its total lifetime energy production, expressed in $/kWh. LCOE accounts for installed cost, financing, operations and maintenance, and system degradation — typically 0.5–0.7% per year for crystalline silicon modules per NREL data.
Payback period: The time required for cumulative energy bill savings to equal the net installed cost of a PV system after applicable incentives. Georgia-specific payback estimates depend on utility rates, system production, and financing structure; see Solar ROI and Payback Period in Georgia.
Permitting and inspection terms
Building permit: A local government authorization required before solar installation begins. In Georgia, building permits for PV systems are issued under the Georgia State Minimum Standard Building Code, which adopts the International Building Code (IBC) and International Residential Code (IRC) with state amendments. The Georgia Department of Community Affairs (DCA) administers code adoption.
Electrical permit: A separate permit required for the electrical work associated with a PV installation, issued under the National Electrical Code (NEC) as adopted by Georgia. NEC Article 690