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Solar Energy Wiki

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250 concepts · 176 concept relationships · counts derived from the ontology registry

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Published concepts 250

  • Solar energyPublished

    Solar energy is radiant energy from the sun that can be captured and converted into useful forms of energy.

    GS-CONCEPT-001 · Foundation · Source event date unavailable
  • PhotovoltaicsPublished

    Photovoltaics is the conversion of sunlight into electricity using semiconductor materials in solar cells.

    GS-CONCEPT-002 · Foundation · Source event date unavailable

  • A residential photovoltaic system is a set of photovoltaic modules and supporting electrical equipment configured to supply electricity for a home.

    GS-CONCEPT-003 · Technology · Source event date unavailable

  • A photovoltaic module is an assembly of connected photovoltaic cells that produces direct-current electricity from sunlight.

    GS-CONCEPT-004 · Technology · Source event date unavailable

  • A solar inverter is equipment that converts direct-current electricity from a photovoltaic system into alternating-current electricity.

    GS-CONCEPT-005 · Technology · Source event date unavailable

  • Solar battery storage stores electricity associated with a solar energy system for use at another time.

    GS-CONCEPT-006 · Technology · Source event date unavailable
  • KilowattPublished

    A kilowatt is a unit of power equal to 1,000 watts.

    GS-CONCEPT-007 · Measurement · Source event as of June 25, 2026
  • Kilowatt-hourPublished

    A kilowatt-hour is a unit of energy equal to using one kilowatt of power for one hour.

    GS-CONCEPT-008 · Measurement · Source event as of June 25, 2026

  • Solar system size is the rated power capacity of a photovoltaic system, commonly expressed in kilowatts.

    GS-CONCEPT-009 · Measurement · Source event date unavailable

  • Annual solar production is the amount of electrical energy a photovoltaic system generates over a year.

    GS-CONCEPT-010 · Measurement · Source event date unavailable

  • Electricity pricing is the set of prices and rate structures used to charge customers for electricity service.

    GS-CONCEPT-011 · Grid · Source event date unavailable
  • Net meteringPublished

    Net metering is a billing mechanism that credits a customer for eligible electricity exported to the grid.

    GS-CONCEPT-012 · Grid · Source event as of February 1, 2021
  • Net billingPublished

    Net billing is a billing arrangement that values electricity exported to the grid separately from electricity imported from the grid.

    GS-CONCEPT-013 · Grid · Source event as of February 1, 2021

  • A time-of-use electricity rate charges different prices for electricity during predefined periods within a day.

    GS-CONCEPT-014 · Grid · Source event as of July 14, 2020

  • Payback period is the time required for cumulative savings or cash flows to recover an initial investment.

    GS-CONCEPT-015 · Economics · Source event as of August 1, 2024

  • Community solar is an off-site solar project whose electricity or associated bill credits are shared by multiple participating customers.

    GS-CONCEPT-016 · Access · Source event date unavailable

  • Residential solar installed price is the gross price paid for an installed residential photovoltaic system before incentives, subject to the inclusions and exclusions of the source dataset or quote.

    GS-CONCEPT-017 · Economics · Source event as of December 31, 2023
  • Solar loanPublished

    A solar loan is consumer credit used to purchase residential solar equipment and installation; the borrower owns the purchased system and repays principal and the applicable cost of credit under the agreement.

    GS-CONCEPT-018 · Economics · Source event as of August 7, 2024

  • A residential solar system lease is an agreement in which a provider owns a system installed at a home and the customer pays scheduled amounts for its use during the contract term.

    GS-CONCEPT-019 · Economics · Source event as of August 7, 2024

  • A residential on-site solar power purchase agreement is a contract in which a third-party provider owns and operates a photovoltaic system at a home and the customer purchases the system's generated electricity at a contracted kilowatt-hour price for a defined term.

    GS-CONCEPT-020 · Economics · Source event as of April 9, 2026

  • Solar-loan dealer fee is an industry term used for a financing-related upfront fee or markup in some solar-specific loan programs that may be reflected in the financed system price or contractual principal/note amount.

    GS-CONCEPT-021 · Economics · Source event as of August 7, 2024
  • Solar arrayPublished

    A solar array is an electrically connected group of photovoltaic modules configured to operate as part of one photovoltaic system.

    GS-CONCEPT-022 · Technology · Source event as of September 1, 2014

  • A roof-mounted photovoltaic system is a photovoltaic system whose module array and mounting structure are installed on a building roof.

    GS-CONCEPT-023 · Technology · Source event as of May 15, 2026

  • A ground-mounted photovoltaic system supports a photovoltaic array on a structure anchored to the ground rather than to a roof.

    GS-CONCEPT-024 · Technology · Source event date unavailable

  • A string inverter converts direct-current electricity from one or more series-connected groups of photovoltaic modules into alternating-current electricity.

    GS-CONCEPT-025 · Technology · Source event as of March 31, 2025
  • MicroinverterPublished

    A microinverter is an inverter installed at an individual photovoltaic module to convert that module's direct-current output into alternating current.

    GS-CONCEPT-026 · Technology · Source event date unavailable

  • Building-integrated photovoltaics are photovoltaic materials or products that also perform a building-envelope function such as roofing, glazing, or facade cladding.

    GS-CONCEPT-027 · Technology · Source event date unavailable

  • A photovoltaic racking system is the structural mounting assembly that supports and positions photovoltaic modules on a roof, the ground, or another structure.

    GS-CONCEPT-028 · Technology · Source event date unavailable

  • A smart solar inverter is an inverter with communication and grid-support functions in addition to direct-current to alternating-current conversion.

    GS-CONCEPT-029 · Technology · Source event date unavailable

  • An electrical service panel upgrade replaces or modifies service equipment so the electrical installation can meet the requirements of the proposed work and applicable code.

    GS-CONCEPT-030 · Technology · Source event as of August 27, 2015

  • Photovoltaic system monitoring records or presents operating data from a photovoltaic system so performance and status can be reviewed over time.

    GS-CONCEPT-031 · Technology · Source event as of December 1, 2018

  • Solar irradiance is solar power incident on a surface per unit area at a particular time.

    GS-CONCEPT-032 · Measurement · Source event as of September 25, 2025

  • Peak sun hours express daily solar irradiation as the equivalent number of hours at a reference irradiance of one kilowatt per square meter.

    GS-CONCEPT-033 · Measurement · Source event as of January 1, 2011

  • Photovoltaic shading loss is the reduction in modeled or measured photovoltaic output associated with solar radiation blocked from modules by surrounding objects or terrain.

    GS-CONCEPT-034 · Measurement · Source event as of September 1, 2014

  • Solar array azimuth is the compass direction toward which the array surface faces, expressed under a stated angular convention.

    GS-CONCEPT-035 · Measurement · Source event as of September 25, 2025

  • Solar array tilt is the angle between the photovoltaic array surface and the horizontal plane.

    GS-CONCEPT-036 · Measurement · Source event as of September 25, 2025

  • Photovoltaic module efficiency is the ratio of module electrical power output to incident solar power under stated test conditions.

    GS-CONCEPT-037 · Measurement · Source event as of May 5, 2026

  • A photovoltaic temperature coefficient describes how a specified module electrical characteristic changes with cell temperature relative to stated reference conditions.

    GS-CONCEPT-038 · Measurement · Source event as of August 1, 2004

  • Inverter clipping occurs when available direct-current photovoltaic power exceeds the inverter's ability to convert and deliver alternating-current power at that moment.

    GS-CONCEPT-039 · Measurement · Source event as of September 1, 2014

  • Photovoltaic system loss is a modeled or measured reduction between an identified reference energy and delivered photovoltaic energy attributable to specified loss mechanisms.

    GS-CONCEPT-040 · Measurement · Source event as of September 1, 2014

  • Photovoltaic performance ratio compares delivered system energy with a reference yield based on in-plane irradiation and installed capacity over the same period.

    GS-CONCEPT-041 · Measurement · Source event as of December 17, 2023

  • Photovoltaic capacity factor is electrical energy generated over a period divided by the energy that would result from operating at the stated rated capacity throughout that period.

    GS-CONCEPT-042 · Measurement · Source event as of December 17, 2023

  • Photovoltaic degradation rate describes the change in a system or module performance metric over time under a stated method and period.

    GS-CONCEPT-043 · Measurement · Source event as of April 1, 2012

  • Battery energy capacity is the amount of electrical energy a battery system is specified or demonstrated to store under stated conditions.

    GS-CONCEPT-044 · Measurement · Source event as of December 1, 2023

  • Usable battery capacity is the portion of stored energy made available between the system's allowed upper and lower state-of-charge limits under specified conditions.

    GS-CONCEPT-045 · Measurement · Source event as of December 1, 2023

  • Battery power rating is the rate at which a battery system can charge or discharge electrical energy under stated operating limits.

    GS-CONCEPT-046 · Measurement · Source event as of December 1, 2023

  • Battery depth of discharge is the fraction or percentage of a stated battery capacity that has been withdrawn relative to a defined full condition.

    GS-CONCEPT-047 · Measurement · Source event as of December 1, 2023

  • Battery round-trip efficiency is delivered discharge energy divided by charge energy over a defined charge-and-discharge test boundary.

    GS-CONCEPT-048 · Measurement · Source event as of December 1, 2023

  • Battery state of charge estimates the energy remaining in a battery relative to a defined available or rated capacity.

    GS-CONCEPT-049 · Measurement · Source event as of December 1, 2023

  • Battery cycle life is the number of defined charge-discharge cycles completed before a specified performance endpoint is reached under stated test conditions.

    GS-CONCEPT-050 · Measurement · Source event as of December 1, 2023

  • Residential backup power is electricity supplied to selected or whole-home loads when normal utility service is unavailable, using equipment configured for that operating mode.

    GS-CONCEPT-051 · Technology · Source event as of January 1, 2018

  • A critical loads panel is a distribution panel or designated load grouping arranged so selected circuits can be supplied by a backup power system.

    GS-CONCEPT-052 · Technology · Source event as of December 1, 2018

  • Solar-storage islanding is an intentional operating mode in which approved equipment isolates selected local loads from the utility grid and supplies them from local generation or storage.

    GS-CONCEPT-053 · Technology · Source event date unavailable

  • Grid interconnection is the technical and administrative process for connecting a customer energy system to an electric utility distribution system under applicable requirements.

    GS-CONCEPT-054 · Grid · Source event as of September 7, 2021

  • An interconnection agreement is the controlling agreement between the system owner or customer and the utility for an approved connection and its operating conditions.

    GS-CONCEPT-055 · Grid · Source event as of May 16, 2024

  • Permission to operate is a utility's authorization for an interconnected customer system to begin operating under the utility's stated conditions after required project steps are complete.

    GS-CONCEPT-056 · Grid · Source event date unavailable

  • A photovoltaic export limit is a configured or contractual maximum on power delivered from a customer photovoltaic system to the utility grid.

    GS-CONCEPT-057 · Grid · Source event as of September 30, 2020

  • A non-export photovoltaic system is designed or controlled so electricity is not intentionally delivered from the customer site to the utility grid under the applicable interconnection arrangement.

    GS-CONCEPT-058 · Grid · Source event as of September 30, 2020

  • A distributed energy resource is a comparatively small generation, storage, demand-response, efficiency, thermal-storage, or similar resource connected on a distribution system or behind a customer meter.

    GS-CONCEPT-059 · Grid · Source event as of September 28, 2020

  • Behind-the-meter generation is electricity generation located on the customer side of the utility billing meter or other defined customer-grid boundary.

    GS-CONCEPT-060 · Grid · Source event as of September 28, 2020

  • An electricity fixed charge is a bill charge determined independently of the customer's metered kilowatt-hour consumption during the billing period under the applicable rate schedule.

    GS-CONCEPT-061 · Grid · Source event as of May 13, 2020

  • An electricity demand charge is the portion of an electric-service bill based on the customer's measured or calculated maximum capacity usage under the applicable rate schedule.

    GS-CONCEPT-062 · Grid · Source event as of May 13, 2020

  • A tiered electricity rate applies different energy prices to defined blocks of electricity consumption within a billing period.

    GS-CONCEPT-063 · Grid · Source event as of September 1, 2009

  • An export compensation rate is the monetary or bill-credit value assigned to eligible electricity delivered from a customer energy system to the grid under a specified program or tariff.

    GS-CONCEPT-064 · Grid · Source event as of February 1, 2021

  • An avoided-cost rate is a value based on costs a utility or system avoids because a specified increment of electricity or service is supplied by another resource.

    GS-CONCEPT-065 · Grid · Source event as of February 1, 2021

  • A photovoltaic production estimate is modeled electrical energy output for a specified photovoltaic system, location, weather dataset, period, and set of assumptions.

    GS-CONCEPT-066 · Measurement · Source event as of September 25, 2025

  • Photovoltaic specific yield is energy generated over a period divided by the photovoltaic system's stated rated capacity, commonly expressed as kilowatt-hours per kilowatt.

    GS-CONCEPT-067 · Measurement · Source event as of September 25, 2025

  • Solar self-consumption is photovoltaic electricity used by loads behind the relevant customer meter instead of being exported to the grid.

    GS-CONCEPT-068 · Economics · Source event as of February 1, 2021

  • Battery load shifting charges storage during one time period and discharges it during another to change the timing of grid imports, exports, or onsite energy use.

    GS-CONCEPT-069 · Economics · Source event as of December 17, 2023

  • Avoided utility cost is the charge a customer does not incur because onsite generation, storage, or a load change reduces a billable utility quantity under the applicable tariff.

    GS-CONCEPT-070 · Economics · Source event as of December 17, 2023

  • A residual utility bill is the utility bill that remains after the applicable effects of onsite generation, storage, credits, and tariff rules are applied for a billing period.

    GS-CONCEPT-071 · Economics · Source event as of December 17, 2023

  • Solar project cash flow is a dated series of money received and paid for a defined solar ownership or contract perspective over an analysis period.

    GS-CONCEPT-072 · Economics · Source event as of December 17, 2023

  • Net present value is the sum of a defined series of cash flows discounted to one valuation date using a stated discount rate and timing convention.

    GS-CONCEPT-073 · Economics · Source event as of December 17, 2023

  • Internal rate of return is a discount rate at which the net present value of a specified cash-flow series equals zero, when such a solution is defined.

    GS-CONCEPT-074 · Economics · Source event as of December 17, 2023

  • Levelized cost of energy is a discounted lifetime cost measure divided by a discounted lifetime energy measure under a specified method and boundary.

    GS-CONCEPT-075 · Economics · Source event as of December 17, 2023

  • A solar cash purchase is a customer-owned solar purchase whose project acquisition cash flow does not include debt or third-party ownership payments in the modeled transaction.

    GS-CONCEPT-076 · Economics · Source event as of May 15, 2026

  • A solar owner purchase is an acquisition arrangement in which the customer obtains ownership of the installed solar system, using cash or a separate financing obligation.

    GS-CONCEPT-077 · Economics · Source event as of May 15, 2026

  • Annual percentage rate is a measure of the cost of credit expressed as a yearly rate that relates value received by the consumer to the amount and timing of payments under the applicable disclosure rules.

    GS-CONCEPT-078 · Economics · Source event as of January 30, 2024

  • Amount financed is the net amount of credit extended for the consumer's use as calculated under the applicable credit-disclosure rule.

    GS-CONCEPT-079 · Economics · Source event as of August 7, 2024

  • A finance charge is the cost of consumer credit expressed as a dollar amount under the applicable disclosure rule, including charges included by that rule and excluding charges it excludes.

    GS-CONCEPT-080 · Economics · Source event as of August 7, 2024

  • Total of payments is the amount a consumer will have paid after making all scheduled payments under the disclosed credit obligation, as defined by the applicable rule.

    GS-CONCEPT-081 · Economics · Source event date unavailable

  • A solar loan term is the contractual period over which scheduled obligations for a solar-financing loan are due, subject to the agreement's maturity and payment provisions.

    GS-CONCEPT-082 · Economics · Source event as of August 7, 2024

  • A secured solar loan is credit used for a solar purchase that is backed by a security interest or lien in identified property under the agreement and applicable law.

    GS-CONCEPT-083 · Economics · Source event as of August 7, 2024

  • An unsecured solar loan is credit used for a solar purchase that is not backed by collateral identified as securing that obligation under the agreement.

    GS-CONCEPT-084 · Economics · Source event as of August 7, 2024

  • A solar lease escalator is a contract provision that changes scheduled lease payments over time according to a stated rate, amount, index, or formula.

    GS-CONCEPT-085 · Economics · Source event as of August 7, 2024

  • A solar PPA escalator is a contract provision that changes the price paid for generated electricity over time according to a stated rate, amount, index, or formula.

    GS-CONCEPT-086 · Economics · Source event as of July 28, 2026

  • A solar contract buyout is a transaction permitted by a lease or power purchase agreement in which specified rights or system ownership are acquired for a contract-determined amount and under stated conditions.

    GS-CONCEPT-087 · Economics · Source event date unavailable

  • A residential solar quote is a seller's or installer's stated price and proposed scope for specified equipment, design assumptions, services, and commercial terms at a point in time.

    GS-CONCEPT-088 · Economics · Source event as of May 15, 2026

  • A residential solar contract is the executed agreement that states the parties' rights and obligations for a residential solar sale, installation, financing, lease, PPA, service, or related transaction.

    GS-CONCEPT-089 · Economics · Source event as of August 7, 2024

  • Solar permitting is the local or other authority's administrative and technical review process for proposed solar construction and electrical work before and after installation as required.

    GS-CONCEPT-090 · Policy · Source event as of December 17, 2025

  • A solar inspection is an examination by an authorized inspector to determine whether installed solar-related work complies with the applicable approved plans, codes, and local requirements.

    GS-CONCEPT-091 · Policy · Source event as of December 17, 2025

  • Photovoltaic system commissioning is the documented process of inspecting, testing, configuring, and confirming an installed system against defined design and operational requirements before handoff or operation.

    GS-CONCEPT-092 · Technology · Source event as of January 1, 2011

  • A solar workmanship warranty is an installer's or contractor's written promise covering specified defects in installation work for stated periods, remedies, conditions, and exclusions.

    GS-CONCEPT-093 · Economics · Source event as of February 1, 2024

  • A solar equipment warranty is a manufacturer's or supplier's written promise for specified equipment defects, performance, parts, or remedies under stated conditions and periods.

    GS-CONCEPT-094 · Economics · Source event as of February 1, 2024

  • A solar production guarantee is a contract promise that compares defined measured or calculated system production with a stated schedule and provides specified remedies when its conditions are met.

    GS-CONCEPT-095 · Economics · Source event date unavailable

  • A renewable energy certificate is a uniquely tracked instrument representing specified non-power attributes associated with one megawatt-hour of eligible renewable electricity generation under an applicable tracking and program framework.

    GS-CONCEPT-096 · Policy · Source event as of March 5, 2024

  • A solar renewable energy certificate is a renewable energy certificate created from eligible solar electricity generation under a program that recognizes a solar-specific certificate class.

    GS-CONCEPT-097 · Policy · Source event as of March 5, 2024

  • Renewable energy certificate ownership is the legal or contractual entitlement to control, transfer, or retire the certificate attributes associated with eligible generation under the relevant agreement and tracking rules.

    GS-CONCEPT-098 · Policy · Source event as of March 5, 2024

  • A residential solar incentive is a program benefit tied to qualifying residential solar property, generation, participation, financing, or related activity under the program's current rules.

    GS-CONCEPT-099 · Policy · Source event as of May 15, 2026

  • Solar incentive eligibility is the determination that a specific applicant, property, project, expenditure, date, ownership arrangement, and required documentation satisfy a named program's controlling conditions.

    GS-CONCEPT-100 · Policy · Source event as of May 15, 2026

  • NREL documents DC power optimizers as module-level power electronics and lists module-level monitoring and troubleshooting as a supported capability.

    GS-CONCEPT-101 · Technology · Source event as of September 2017

  • NREL SAM describes a hybrid inverter as an inverter with inputs for both a photovoltaic array and battery.

    GS-CONCEPT-102 · Technology · Source event date unavailable

  • NREL SAM places a DC-connected battery on the DC side of a hybrid photovoltaic inverter.

    GS-CONCEPT-103 · Technology · Source event date unavailable

  • Morningstar identifies SunGuard as a solar battery charge controller.

    GS-CONCEPT-104 · Technology · Source event date unavailable

  • UL describes PV rapid-shutdown system equipment as equipment used with other PV-system equipment to perform rapid-shutdown functions.

    GS-CONCEPT-105 · Technology · Source event as of 2015

  • DOE lists combiner boxes as balance-of-system hardware.

    GS-CONCEPT-106 · Technology · Source event date unavailable

  • DOE lists disconnects as balance-of-system hardware.

    GS-CONCEPT-107 · Technology · Source event date unavailable

  • Enphase describes a dedicated AC disconnect switch located in series with a combined PV inverter circuit.

    GS-CONCEPT-108 · Technology · Source event date unavailable

  • NFPA's 2018 revision defines a PV source circuit as DC conductors between modules and from modules to DC combiners, electronic power converters, or a DC PV system disconnecting means.

    GS-CONCEPT-109 · Technology · Source event as of January 17, 2018

  • NFPA's 2018 revision defines a PV output circuit as DC conductors between PV source circuits and an inverter or DC utilization equipment.

    GS-CONCEPT-110 · Technology · Source event as of January 17, 2018

  • DOE's rack-mounted-systems guide describes mounting feet, struts, bolts, and attachments at roof penetrations.

    GS-CONCEPT-111 · Technology · Source event as of 2007

  • DOE's rack-mounted-systems guide discusses flashing where roof-mounted system penetrations are used.

    GS-CONCEPT-112 · Technology · Source event as of 2007

  • DOE identifies grounding as a safety feature to incorporate in photovoltaic-system equipment.

    GS-CONCEPT-113 · Technology · Source event date unavailable

  • NFPA's photovoltaic draft text describes identified devices used for bonding PV module frames.

    GS-CONCEPT-114 · Technology · Source event as of October 30, 2018

  • DOE identifies electrical conduits as part of its photovoltaic electrical-equipment considerations.

    GS-CONCEPT-115 · Technology · Source event date unavailable

  • DOE says a photovoltaic module is fitted with a junction box where ribbons connect to diodes.

    GS-CONCEPT-116 · Technology · Source event date unavailable

  • DOE says electrical cables from a module junction box convey the current produced by the module.

    GS-CONCEPT-117 · Technology · Source event date unavailable

  • DOE says metering energy generation for a solar photovoltaic system is important to operations and maintenance.

    GS-CONCEPT-118 · Technology · Source event date unavailable

  • DOE's PV monitoring diagram compares a production model with data measured from a production meter.

    GS-CONCEPT-119 · Technology · Source event date unavailable

  • DOE describes a solar-building prototype that interfaces with an adaptive battery management system.

    GS-CONCEPT-120 · Technology · Source event as of November 7, 2017

  • NREL PVWatts reports plane-of-array irradiance as solar irradiance at the array plane.

    GS-CONCEPT-121 · Measurement · Source event date unavailable

  • NREL SAM lists global horizontal irradiance as a weather-data element for photovoltaic modeling.

    GS-CONCEPT-122 · Measurement · Source event as of April 16, 2025

  • NREL SAM lists direct normal irradiance as a weather-data element for photovoltaic modeling.

    GS-CONCEPT-123 · Measurement · Source event as of April 16, 2025

  • NREL SAM lists diffuse horizontal irradiance as a weather-data element for photovoltaic modeling.

    GS-CONCEPT-124 · Measurement · Source event as of April 16, 2025

  • NREL documents albedo as ground reflectance in PVWatts V8 model inputs.

    GS-CONCEPT-125 · Measurement · Source event date unavailable
  • Bifacial gainPublished

    NREL documents bifacial-model inputs for rear-side irradiance and module bifaciality in SAM.

    GS-CONCEPT-126 · Measurement · Source event as of April 16, 2025

  • NREL PVWatts defines the DC-to-AC ratio as a positive model input with a default value of 1.2.

    GS-CONCEPT-127 · Measurement · Source event date unavailable

  • NREL PVWatts documents inverter efficiency at rated power as the inv_eff model input.

    GS-CONCEPT-128 · Measurement · Source event date unavailable

  • NREL SAM identifies module-voltage mismatch as an electrical loss input on the detailed-PV model Losses page.

    GS-CONCEPT-129 · Measurement · Source event as of April 16, 2025

  • NREL PVWatts defines soiling as a reduction in incident solar irradiance from dust or other seasonal module-surface soiling.

    GS-CONCEPT-130 · Measurement · Source event date unavailable

  • DOE FEMP defines PV availability as the percentage of time a system is operational and capable of delivering power when the solar resource and grid are working.

    GS-CONCEPT-131 · Measurement · Source event as of May 20, 2026

  • NREL SAM documents Annual Energy and Energy Yield as photovoltaic performance metrics.

    GS-CONCEPT-132 · Measurement · Source event as of April 16, 2025

  • NREL documents weather-corrected PV performance methods that use calibrated irradiance and measured environmental inputs.

    GS-CONCEPT-133 · Measurement · Source event as of 2013

  • NREL Standard Work Specifications calls for system performance benchmark data in photovoltaic owner documentation.

    GS-CONCEPT-134 · Measurement · Source event date unavailable

  • Nominal operating cell temperature (NOCT) is a PV module’s measured cell temperature under the defined NOCT test conditions of 800 W/m² incident irradiance, 20°C ambient temperature, and 1 m/s wind speed.

    GS-CONCEPT-135 · Measurement · Source event as of April 16, 2025
  • PyranometerPublished

    NREL's weather-corrected performance guidance uses a calibrated pyranometer to measure horizontal irradiance.

    GS-CONCEPT-136 · Measurement · Source event as of 2013

  • NREL's weather-corrected performance guidance uses calibrated reference cells or modules to determine plane-of-array irradiance.

    GS-CONCEPT-137 · Measurement · Source event as of 2013

  • NREL's weather-corrected performance guidance uses a shielded thermocouple or equivalent RTD surface-mounted on a module to measure module temperature.

    GS-CONCEPT-138 · Measurement · Source event as of 2013

  • DOE FEMP says power-conditioning equipment such as inverters often include metering and instrumentation that report parameters to a monitoring system.

    GS-CONCEPT-139 · Measurement · Source event date unavailable

  • DOE FEMP says a PV monitoring platform may receive utility control signals for setpoints such as curtailment of power delivery.

    GS-CONCEPT-140 · Measurement · Source event date unavailable

  • NREL reports low-irradiance losses of photovoltaic modules as a module-efficiency behavior considered in PV energy-performance analysis.

    GS-CONCEPT-141 · Measurement · Source event date unavailable

  • CFPB describes principal as the amount borrowed before interest is added.

    GS-CONCEPT-142 · Economics · Source event as of January 23, 2025

  • CFPB defines a loan interest rate as a percentage charged for borrowing money.

    GS-CONCEPT-143 · Economics · Source event as of January 23, 2025

  • CFPB explains amortization as paying off debt over time through scheduled regular payments.

    GS-CONCEPT-144 · Economics · Source event as of September 25, 2024

  • A solar-loan monthly payment is a scheduled installment amount when a loan agreement uses monthly payment timing.

    GS-CONCEPT-145 · Economics · Source event as of September 25, 2024

  • CFPB defines prepayment as paying all or part of a loan before the payment is due.

    GS-CONCEPT-146 · Economics · Source event as of January 23, 2025

  • CFPB defines a prepayment penalty as a fee that a lender may charge when a borrower pays all or part of a loan early.

    GS-CONCEPT-147 · Economics · Source event as of January 23, 2025

  • A solar-loan lien is a security interest or encumbrance described by the applicable financing arrangement, rather than a feature of every solar loan.

    GS-CONCEPT-148 · Economics · Source event as of January 23, 2025

  • California Commercial Code defines a financing statement as a record or records composed of an initial financing statement and related amendments.

    GS-CONCEPT-149 · Economics · Source event as of January 1, 2024

  • Solar-financing transfer is an editorial umbrella for the financing obligation considered when a home with solar is sold.

    GS-CONCEPT-150 · Economics · Source event as of August 7, 2024

  • A solar building permit application is the City of San Diego's stated application process for a photovoltaic project under the applicable permit route.

    GS-CONCEPT-151 · Policy · Source event date unavailable

  • A solar electrical permit is the electrical or combination-permit path identified by San Diego IB-301 for qualifying photovoltaic work.

    GS-CONCEPT-152 · Policy · Source event date unavailable

  • Solar zoning review is the local review item San Diego IB-301 identifies for photovoltaic work in the specified zoning circumstances.

    GS-CONCEPT-153 · Policy · Source event date unavailable

  • Solar plan review is the City review of the plans and documentation required by the applicable photovoltaic permit route.

    GS-CONCEPT-154 · Policy · Source event date unavailable

  • A solar permit fee is a City of San Diego fee category associated with the applicable photovoltaic permit process.

    GS-CONCEPT-155 · Policy · Source event date unavailable

  • A solar ordinance is an editorial label here for City of San Diego municipal-code rules that govern photovoltaic facilities.

    GS-CONCEPT-156 · Policy · Source event date unavailable

  • Solar access ordinance is an editorial label here for California expedited-permitting rules for eligible small residential rooftop solar energy systems.

    GS-CONCEPT-157 · Policy · Source event as of January 1, 2020

  • A solar easement is a California written instrument authorized by Civil Code § 801.5 for specified solar-access purposes.

    GS-CONCEPT-158 · Policy · Source event as of January 1, 2022

  • An HOA solar restriction is a covenant, restriction, or condition affecting a solar-energy system under the scope of California Civil Code § 714.

    GS-CONCEPT-159 · Policy · Source event as of January 1, 2015

  • HOA solar approval is the qualifying-association application process addressed by California Civil Code § 714(e).

    GS-CONCEPT-160 · Policy · Source event as of January 1, 2015

  • Historic resource solar review is the City of San Diego process for development that may affect the historical resources covered by its regulations.

    GS-CONCEPT-161 · Policy · Source event date unavailable

  • A solar fire access pathway is a City of San Diego photovoltaic review topic identified in IB-301 as Fire Roof Access and Pathways.

    GS-CONCEPT-162 · Policy · Source event date unavailable

  • An adopted building code is the building-code edition and City changes that San Diego incorporates through its local code and adoption ordinance.

    GS-CONCEPT-163 · Policy · Source event as of April 22, 2026

  • An adopted electrical code is the electrical-code edition and City changes that San Diego incorporates through its local code and adoption ordinance.

    GS-CONCEPT-164 · Policy · Source event as of April 22, 2026

  • A solar contractor license is the current California CSLB licensing record relevant to a contractor's authorized solar work.

    GS-CONCEPT-165 · Policy · Source event date unavailable

  • A solar home-improvement contract is a California consumer contract governed by the current requirements in Business and Professions Code § 7159.

    GS-CONCEPT-166 · Policy · Source event as of January 1, 2026

  • A solar disclosure document is the California consumer disclosure artifact described in Business and Professions Code § 7169 for its stated solar-system transactions.

    GS-CONCEPT-167 · Policy · Source event as of January 1, 2022

  • A solar contract cancellation right is a California contract notice and cancellation rule under the applicable arms of Business and Professions Code § 7159.

    GS-CONCEPT-168 · Policy · Source event as of January 1, 2026

  • A solar consumer complaint is a California consumer report that may be directed to CSLB for contractor or home-improvement-salesperson matters under the published complaint materials.

    GS-CONCEPT-169 · Policy · Source event date unavailable

  • A solar scam warning sign is a general consumer caution about false solar claims described in the California Solar Consumer Protection Guide.

    GS-CONCEPT-170 · Policy · Source event as of October 2025

  • An incentive reservation is a program-status step in which an administrator may conditionally or confirmingly reserve funds after its review under the applicable incentive rules.

    GS-CONCEPT-171 · Policy · Source event as of June 17, 2026

  • An upfront solar incentive is an incentive calculated at or near installation under the qualifying program method, such as the SGIP EPBB pathway for specified new photovoltaic systems.

    GS-CONCEPT-172 · Policy · Source event as of June 17, 2026

  • A performance-based incentive is a program payment method tied to the measured or reported performance rules for the eligible technology class specified by that program.

    GS-CONCEPT-173 · Policy · Source event as of June 17, 2026

  • A property-tax solar exclusion is California's statutory appraisal treatment that excludes specified active solar-energy-system construction or additions from the term newly constructed.

    GS-CONCEPT-174 · Policy · Source event as of January 1, 2026

  • A sales-tax solar exemption is a jurisdiction-specific transaction-tax rule; New York's ST-776 describes one example for qualifying residential solar energy systems equipment.

    GS-CONCEPT-175 · Policy · Source event as of May 18, 2026

  • A solar PACE assessment is a property-assessed financing arrangement for which California requires a PACE Financing Estimate and Disclosure before the owner enters a PACE assessment contract.

    GS-CONCEPT-176 · Policy · Source event date unavailable

  • A solar-ready building code is a code requirement that preserves specified design capacity or features for future solar, distinct from a requirement to install photovoltaic equipment.

    GS-CONCEPT-177 · Policy · Source event as of July 15, 2026

  • Expedited solar permitting is California's statutory framework for local streamlined review of qualifying small residential rooftop solar energy systems.

    GS-CONCEPT-178 · Policy · Source event as of January 1, 2020

  • A solar permit checklist is a local agency's organized list of photovoltaic permit-process and submittal information for its stated project categories.

    GS-CONCEPT-179 · Policy · Source event date unavailable

  • A solar CEQA exemption is California's limited statutory environmental-review exemption for qualifying solar energy system projects under Public Resources Code section 21080.35.

    GS-CONCEPT-180 · Policy · Source event as of January 1, 2012

  • A solar land-use permit is a local discretionary permit or review that may be required when a proposed solar development's use, design feature, or location triggers the City of San Diego process.

    GS-CONCEPT-181 · Policy · Source event date unavailable

  • Interconnection approval is SDG&E's written Authorization Required to Operate before a generating facility operates in parallel with the distribution system under Electric Rule 21.

    GS-CONCEPT-182 · Policy · Source event as of August 29, 2023

  • Solar permit expiration is the local end of validity that can apply to a City of San Diego construction permit under the governing expiration provision.

    GS-CONCEPT-183 · Policy · Source event as of September 4, 2024

  • A solar permit amendment is a local construction-change process for modifying work after a City of San Diego building permit has been issued.

    GS-CONCEPT-184 · Policy · Source event as of August 30, 2012

  • The point of common coupling is the point where an SDG&E customer generation facility connects to the utility's distribution system as defined by Electric Rule 21.

    GS-CONCEPT-185 · Grid · Source event as of August 6, 2023

  • The point of interconnection is the physical point where a generating facility connects to the SDG&E distribution system under the Rule 21 definition.

    GS-CONCEPT-186 · Grid · Source event as of August 6, 2023

  • Utility interconnection facilities are the facilities used to interconnect a generating facility under Rule 21, which may be integral to or separate from that facility.

    GS-CONCEPT-187 · Grid · Source event as of August 29, 2023

  • The utility distribution system is the portion of SDG&E's electric system used to distribute electricity as defined by Electric Rule 21.

    GS-CONCEPT-188 · Grid · Source event as of August 29, 2023

  • Nominal operating voltage is an editorial compound label used here to discuss Rule 21's defined term Nominal; it is not itself a defined Rule 21 tariff term.

    GS-CONCEPT-189 · Grid · Source event as of August 29, 2023

  • Voltage regulation is the reliability function of maintaining voltage within an acceptable range on an electric power system, as described in FERC's Reliability Primer.

    GS-CONCEPT-190 · Grid · Source event as of October 9, 2024

  • Reactive power is the portion of electricity that establishes and sustains the electric and magnetic fields of alternating-current equipment.

    GS-CONCEPT-191 · Grid · Source event date unavailable
  • Power factorPublished

    Power factor is the ratio of real power in kilowatts to apparent power in kilovolt-amperes for a given load and time.

    GS-CONCEPT-192 · Grid · Source event date unavailable

  • Volt-VAR control is a smart-inverter control represented by a curve relating voltage and reactive-power settings in NREL's described study.

    GS-CONCEPT-193 · Grid · Source event as of January 4, 2023

  • Volt-Watt control is a smart-inverter control represented by a curve relating voltage and real-power settings in NREL's described study.

    GS-CONCEPT-194 · Grid · Source event as of January 4, 2023

  • Frequency-Watt control is a real-power-versus-frequency curve described in NREL's technical report.

    GS-CONCEPT-195 · Grid · Source event as of July 2016

  • Ride-through capability describes a DER capability for voltage or frequency abnormal conditions in NREL's technical report.

    GS-CONCEPT-196 · Grid · Source event as of July 2016

  • Anti-islanding protection is the Rule 21 tariff concept addressing an unintentional island, without establishing compliance for any specific device.

    GS-CONCEPT-197 · Grid · Source event as of August 29, 2023

  • Smart-inverter function profile is GeoStellar's editorial grouping for the function-related settings listed in SDG&E Rule 21 Table Hh-4; it is not a Rule 21-defined national profile.

    GS-CONCEPT-198 · Grid · Source event as of August 29, 2023

  • Smart-inverter commissioning settings is GeoStellar's editorial term for applicable settings verified through the Rule 21 commissioning-testing process.

    GS-CONCEPT-199 · Grid · Source event as of August 29, 2023

  • An interconnection application is the Rule 21 application and interconnection request that starts the utility's review process.

    GS-CONCEPT-200 · Grid · Source event as of August 29, 2023

  • An interconnection study is a Rule 21 process for evaluating distribution-system impacts, facilities, and upgrades for an interconnection request.

    GS-CONCEPT-201 · Grid · Source event as of August 29, 2023

  • Hosting capacity is planning information from integration-capacity analysis, which Resolution E-5440 addresses through utility remediation plans and baseline reporting.

    GS-CONCEPT-202 · Grid · Source event as of April 9, 2026

  • Export control mode is an interconnection configuration that uses Rule 21 non-export or limited-generation-profile options to constrain grid export.

    GS-CONCEPT-203 · Grid · Source event as of July 9, 2025
  • Smart meterPublished

    A smart meter is commonly discussed within EIA's advanced-metering range, from basic hourly interval meters to real-time meters with two-way communication.

    GS-CONCEPT-204 · Grid · Source event as of October 20, 2023

  • Advanced metering infrastructure is a utility-reported technology category in EIA-861 Schedule 6D.

    GS-CONCEPT-205 · Grid · Source event date unavailable

  • In SDG&E Rule 1, an interval meter records usage in 15-minute-or-less intervals for that tariff definition.

    GS-CONCEPT-206 · Grid · Source event as of April 1, 2026
  • Net loadPublished

    In EIA's battery-storage analysis, net load is system load minus nondispatchable wind and solar generation within that analysis boundary.

    GS-CONCEPT-207 · Grid · Source event date unavailable

  • A household load profile is an hourly or subhourly time series of electric-load values in kilowatts for a building.

    GS-CONCEPT-208 · Grid · Source event date unavailable
  • Load controlPublished

    Direct load control is EIA's narrow demand-side-management category in which utility system-operator control can interrupt consumer load at annual peak.

    GS-CONCEPT-209 · Grid · Source event date unavailable

  • Demand response programs involve temporary changes or reductions in electricity use in response to conditions or incentives.

    GS-CONCEPT-210 · Grid · Source event date unavailable

  • A Distributed Energy Resource Provider is an entity authorized by a DER Aggregator to act on its behalf in CAISO markets.

    GS-CONCEPT-211 · Grid · Source event as of May 29, 2026

  • A Distributed Energy Resource Aggregation is a group of distributed energy resources represented in CAISO markets by a DER Aggregator.

    GS-CONCEPT-212 · Grid · Source event as of May 29, 2026

  • FERC says ancillary services help keep the grid stable and resilient by maintaining frequency, reducing voltage fluctuations, helping prevent outages, and responding to sudden changes.

    GS-CONCEPT-213 · Grid · Source event date unavailable

  • Frequency regulation service uses automatic short-term changes in output or demand in response to balancing-authority signals.

    GS-CONCEPT-214 · Grid · Source event as of January 17, 2024

  • Voltage support uses generator reactive-power production to maintain transmission-system voltages within required ranges.

    GS-CONCEPT-215 · Grid · Source event date unavailable

  • Critical peak pricing uses higher prices during a limited number of critical hours.

    GS-CONCEPT-216 · Grid · Source event as of January 17, 2024

  • Real-time pricing uses prices that reflect immediate costs and change frequently.

    GS-CONCEPT-217 · Grid · Source event as of January 17, 2024

  • Photovoltaic operations and maintenance is a combined framework for operating and maintaining PV and energy-storage systems.

    GS-CONCEPT-218 · Technology · Source event as of December 21, 2018

  • Preventive maintenance is work scheduled in advance to prevent failures or reduce their likelihood.

    GS-CONCEPT-219 · Technology · Source event as of December 21, 2018

  • Corrective maintenance is work to repair or replace failed equipment.

    GS-CONCEPT-220 · Technology · Source event as of December 21, 2018

  • Condition-based maintenance uses data logger information to time preventive and corrective maintenance.

    GS-CONCEPT-221 · Technology · Source event as of December 2018

  • A solar maintenance plan is a system-specific O&M record that sets maintenance expectations, records, and contacts.

    GS-CONCEPT-222 · Technology · Source event as of December 2018

  • A solar maintenance log is a chronological record of commissioning, inspection, and O&M activity for a system.

    GS-CONCEPT-223 · Technology · Source event as of December 2018

  • Solar system documentation can include manuals, warranty information, contacts, monitoring information, diagrams, approvals, and performance benchmark data.

    GS-CONCEPT-224 · Technology · Source event as of May 15, 2025

  • A solar as-built drawing records the installed configuration within revision-controlled system documentation.

    GS-CONCEPT-225 · Technology · Source event as of December 2018

  • A solar single-line diagram is an electrical overview showing inverter arrangement and system electrical connections.

    GS-CONCEPT-226 · Technology · Source event as of May 15, 2025

  • A solar equipment datasheet records exact make, model, and electrical and physical specifications for major PV equipment.

    GS-CONCEPT-227 · Technology · Source event as of May 15, 2025

  • A solar operation manual provides equipment-specific operating procedures within O&M-plan documentation.

    GS-CONCEPT-228 · Technology · Source event as of December 2018

  • Solar warranty registration is a product-specific registration step whose effect on coverage must be disclosed when registration is a condition of warranty coverage or performance.

    GS-CONCEPT-229 · Technology · Source event as of December 31, 1975

  • A solar warranty claim follows the product warranty's stated procedure for obtaining performance of a warranty obligation.

    GS-CONCEPT-230 · Technology · Source event as of July 20, 2015

  • A solar service call is a recorded request for a qualified provider to evaluate a reported system condition under an O&M process.

    GS-CONCEPT-231 · Technology · Source event as of December 21, 2018

  • A solar fault code is a manufacturer-formatted alarm code or message used as diagnostic input during equipment maintenance.

    GS-CONCEPT-232 · Technology · Source event as of December 21, 2018

  • An inverter status indicator is an operational display signal, such as a production-meter reading or inverter-faceplate error message, that can be checked over time.

    GS-CONCEPT-233 · Technology · Source event as of May 20, 2026

  • A solar monitoring data gap is an absence of expected monitoring records that should be identified as a data-quality concern before a performance calculation is interpreted.

    GS-CONCEPT-234 · Technology · Source event as of December 21, 2018

  • A solar visual inspection is a structured observation of accessible PV components and visible site conditions in an O&M checklist.

    GS-CONCEPT-235 · Technology · Source event as of December 21, 2018

  • A solar thermal inspection uses infrared images to locate temperature variations in PV equipment.

    GS-CONCEPT-236 · Technology · Source event as of December 21, 2018

  • An insulation resistance test checks a PV circuit for an abnormal leakage path to ground.

    GS-CONCEPT-237 · Technology · Source event as of October 1, 2015

  • An I-V curve test traces DC-array electrical response to investigate array performance and possible faults.

    GS-CONCEPT-238 · Technology · Source event as of December 21, 2018

  • Ground-fault detection monitors for a possible unintended current path and related electrical hazard.

    GS-CONCEPT-239 · Technology · Source event as of January 1, 2016

  • Arc-fault detection evaluates electrical signals consistent with arcing against electrical noise for interruption decisions.

    GS-CONCEPT-240 · Technology · Source event as of June 1, 2011

  • A solar roof leak is a building-envelope concern recorded alongside the PV system when water entry is observed near a solar installation.

    GS-CONCEPT-241 · Technology · Source event as of December 21, 2018

  • Solar vegetation management is the site-maintenance review of vegetation that may affect PV access or shading conditions.

    GS-CONCEPT-242 · Technology · Source event as of December 21, 2018

  • Solar module cleaning is an O&M consideration that evaluates soiling and operating context for a particular PV site.

    GS-CONCEPT-243 · Technology · Source event as of December 21, 2018

  • Solar snow management is the consideration of snow-related PV conditions within a site-specific O&M context.

    GS-CONCEPT-244 · Technology · Source event as of December 21, 2018

  • Solar pest damage is a documented observation of a site or equipment condition that may warrant system-specific maintenance review.

    GS-CONCEPT-245 · Technology · Source event as of December 21, 2018

  • Solar corrosion inspection is the review of corrosion-related conditions as an O&M concern across PV materials, environment, and components.

    GS-CONCEPT-246 · Technology · Source event date unavailable

  • Solar electrical connection inspection is qualified review of PV connectors, wiring, and supports for documented condition concerns.

    GS-CONCEPT-247 · Technology · Source event date unavailable

  • Solar inverter replacement is a documented, system-specific O&M decision concerning an existing PV inverter.

    GS-CONCEPT-248 · Technology · Source event as of May 20, 2026

  • Solar module replacement is a documented corrective-maintenance decision for an existing PV system.

    GS-CONCEPT-249 · Technology · Source event as of December 21, 2018

  • Solar decommissioning is the planned transition at the end of a PV system's performance period.

    GS-CONCEPT-250 · Technology · Source event as of May 20, 2026
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