Glossary of Solar Energy Terms for New York System Owners

New York solar system owners encounter a dense set of technical, financial, and regulatory terms at every stage — from roof assessment and interconnection to net metering and incentive programs. This glossary defines the terms most relevant to residential and commercial solar in New York State, grounded in the rules and programs administered by agencies including NYSERDA, the New York Public Service Commission (PSC), and utility operators such as Con Edison and PSEG Long Island. Understanding these definitions helps system owners interpret contracts, utility agreements, and compliance documents accurately. For a broader orientation to how solar works in this state, the New York Solar Authority index provides structured entry points across all major topics.

Definition and scope

A solar energy glossary, in the context of New York system ownership, is a structured reference that maps technical jargon to precise, operationally relevant definitions. Terms are drawn from four overlapping domains: electrical engineering (inverter, DC/AC, string configuration), utility regulation (interconnection, net metering, standby charges), incentive administration (Megawatt Block, VDER, SRECs), and building and permitting codes (NEC Article 690, fire setbacks, AHJ).

The scope of this page is New York State residential and commercial solar installations connected to the electric grid or operating as off-grid systems. It does not address solar thermal (hot water) systems, utility-scale generation projects above 5 MW, or federal programs not administered through New York State agencies. Definitions are drawn from NYSERDA program documentation, PSC orders, and published standards from the National Electrical Code (NEC) and UL. Legal interpretation of any term for contractual or compliance purposes falls outside this page's scope.

For the conceptual framework underlying how solar installations function physically and within utility infrastructure, see How New York Solar Energy Systems Work.

How it works

Solar energy terminology operates across three layers that interact during a typical installation.

Layer 1 — Physical system components

1. Photovoltaic (PV) module: A panel containing photovoltaic cells that convert sunlight into direct current (DC) electricity. Rated output is expressed in watts peak (Wp) under Standard Test Conditions (STC): 1,000 W/m² irradiance, 25°C cell temperature (NIST, STC definition).
2. Inverter: A device that converts DC output from panels into alternating current (AC) usable by household loads and the utility grid. Three primary types exist: string inverters (one per array), microinverters (one per panel), and power optimizers paired with a string inverter.
3. Array: The complete collection of PV modules wired together on a roof or ground-mount structure.
4. Battery storage / BESS: A Battery Energy Storage System stores surplus solar energy for later dispatch. New York's solar battery storage integration rules govern how storage systems interact with net metering and standby tariffs.

Layer 2 — Utility and grid terminology

1. Interconnection: The formal process by which a solar system is electrically connected to the utility distribution grid. In New York, interconnection standards are set by PSC Case 20-E-0251 for systems up to 5 MW (NYPSC).
2. Net metering (NEM): A billing mechanism under which excess solar generation exported to the grid offsets the owner's consumption charges on a kilowatt-hour-for-kilowatt-hour basis, subject to the applicable utility tariff. The New York net metering policy page covers current PSC rules in detail.
3. VDER (Value of Distributed Energy Resources): A compensation methodology used for community solar and certain behind-the-meter systems that credits exported energy at a calculated "value stack" rate rather than the retail rate. Components include energy, capacity, environmental, and demand reduction values (NYSERDA VDER overview).
4. Standby charge: A fixed monthly fee utilities may apply to solar customers to recover fixed grid costs not offset by net metering credits.

Layer 3 — Financial and incentive terms

1. ITC (Investment Tax Credit): A federal tax credit equal to 30% of eligible solar system costs, established under 26 U.S.C. § 48(a) (IRS). New York's state-level incentives stack on top of, but are separate from, the ITC.
2. NY-Sun Megawatt Block: A NYSERDA incentive program that awards a fixed dollar-per-watt ($/W) incentive to residential and commercial solar installations. Incentive levels decline in preset "blocks" as installed capacity fills each block (NYSERDA NY-Sun). Detailed block pricing is covered under the NY-Sun Megawatt Block program page.
3. SREC (Solar Renewable Energy Certificate): A tradeable certificate representing 1 megawatt-hour (MWh) of solar generation. New York's NY-Sun program replaced SRECs for most new systems, but legacy SREC contracts may still apply to older installations.

Common scenarios

Scenario A — Interconnection and net metering setup
A homeowner installing a 10 kW rooftop system submits an interconnection application to Con Edison or PSEG Long Island before energizing. Terms encountered include simplified interconnection process (for systems ≤ 25 kW), anti-islanding protection (a safety function that prevents a solar inverter from energizing the grid during an outage), and bi-directional meter (a utility meter that records both import and export). The Con Edison solar interconnection and PSEG Long Island solar interconnection pages map utility-specific procedures.

Scenario B — Incentive claim documentation
A commercial property owner claiming the NY-Sun Megawatt Block incentive must understand MW-dc versus MW-ac (the distinction between panel-rated capacity in DC and inverter output in AC, typically a 1.0–1.2 DC:AC ratio), proof of performance period, and incentive assignment (when the incentive is assigned to the installer rather than the owner). Relevant financial structures appear in New York solar financing options.

Scenario C — Community solar subscription
Subscribers to a community distributed generation (CDG) project receive a bill credit rather than physical electricity. Key terms include subscription size (measured in kW, typically limited to 100% of a subscriber's prior 12-month average monthly usage under PSC rules), host site, and subscriber organization. Full coverage appears on the community distributed generation page.

Scenario D — Property and tax treatment
New York Real Property Tax Law § 487 exempts the added value of a qualifying solar system from property tax assessment for up to 15 years (NY Legislature § 487). The companion New York property tax exemption for solar and New York solar sales tax exemption pages detail eligibility conditions and filing procedures.

Decision boundaries

Understanding which terms apply — and which do not — depends on three classification boundaries.

System size threshold: ≤ 25 kW vs. > 25 kW
Systems at or below 25 kW (AC) qualify for the simplified interconnection process under PSC interconnection rules, requiring fewer technical studies. Systems above 25 kW enter the standard interconnection process, which may trigger an impact study and facilities study before approval. Sizing guidance appears in New York residential solar system sizing and New York commercial solar system sizing.

Grid-tied vs. off-grid
Grid-tied systems are subject to utility interconnection rules, net metering tariffs, and anti-islanding requirements under NEC Article 690.12. Off-grid systems are exempt from interconnection requirements but must still comply with NEC Article 690 for electrical safety and require an Authority Having Jurisdiction (AHJ) permit and inspection. Terms like net metering and standby charge do not apply to off-grid installations. The regulatory context for New York solar energy systems page outlines which PSC rules apply by system type.

Ownership model: purchased vs. leased vs. PPA
- Purchased system: Owner claims ITC, NY-Sun incentive, and property tax exemption directly.
- Leased system: A third-party lessor typically retains ITC eligibility; the owner pays a fixed monthly lease payment and may or may not receive net metering credits depending on lease structure.
- Power Purchase Agreement (PPA): Owner pays a per-kWh rate for solar electricity generated on-site by a third-party-owned system. The developer retains incentive ownership. Comparative analysis of these structures is covered in New York solar lease vs. purchase.

NEC Article 690 safety compliance
All solar PV systems installed in New York must comply with NEC Article 690 (Photovoltaic Systems), adopted as part of New York's Uniform Fire Prevention and Building Code. NEC 690.12 requires rapid shutdown capability for rooftop systems — a safety feature that de-energizes conductors