Long Island Solar Glossary — Plain-English Definitions

How to use this glossary

Long Island Solar Installation Pros provides solar installation help — we are not a licensed installer. This glossary defines the terms homeowners encounter on solar proposals and in planning conversations. Definitions are plain-English and accurate to the New York / Long Island context. None of this is tax advice or program-specific legal advice.

Terms are grouped by category for easier scanning: utility + interconnection, incentives + tax, equipment, financing, installation process, and PSEG-specific.

Utility and interconnection

**Net meter** — A two-way electric meter installed by PSEG Long Island (or your municipal utility) that measures both energy you consume from the grid and energy your solar system exports to the grid. The difference is your billable net usage.

**Net metering** — The billing arrangement under which excess solar generation exported to the grid earns energy credits applied to future bills. PSEG Long Island operates a net-metering program for residential solar customers.

**Interconnection** — The formal process of connecting a residential solar system to the utility grid. The licensed local installer submits the interconnection application; the utility (PSEG or municipal) reviews and approves. Permission to operate is the final approval.

**Permission to operate (PTO)** — The utility-issued approval that lets the homeowner energize the solar system. Comes after install, inspections, and final utility review. The system is not legally operating until PTO is granted.

**Time-of-Day rate / Time-of-Use rate** — A PSEG Long Island rate plan structure where the per-kWh price varies by time of day (peak, off-peak, super-off-peak). Battery storage pairs particularly well with Time-of-Day rates because the battery can shift solar generation to peak-rate evening hours.

**Energy Credit Bank** — Under PSEG Long Island's Time-of-Day net meter program, banks that track separate credits for peak, off-peak, and super-off-peak periods.

**Municipal utility** — A separate electric utility operated by an incorporated village or town rather than PSEG Long Island. On Long Island: Freeport Electric (Village of Freeport), Rockville Centre Electric (Village of Rockville Centre), Greenport Municipal Light (Village of Greenport), Fishers Island Electric Corporation.

Incentives and tax credits

**New York State Solar Energy System Equipment Credit** — A New York State residential income tax credit of 25% of qualified solar equipment expenditures, capped at $5,000. Non-refundable; unused portion carries forward up to 5 tax years (per the New York State Department of Taxation and Finance).

**IRS Residential Clean Energy Credit** — A federal residential tax credit that applied to qualified clean energy property installed from 2022 through December 31, 2025. NOT available for property placed in service after that date. The planning review verifies any active federal program at the time of installation.

**ITC (Investment Tax Credit)** — Sometimes used informally for the federal residential credit; more precisely refers to the federal commercial Investment Tax Credit, which operates under separate rules and is still active. Confirm with tax counsel for the specific project structure.

**NYSERDA** — New York State Energy Research and Development Authority. State entity that administers solar and storage incentive programs. Long Island Solar Installation Pros is NOT a NYSERDA-designated contractor.

**NY-Sun** — NYSERDA's solar incentive program for non-residential and large-scale installations, including commercial and agricultural projects. Organized into Megablocks with incentive levels that update over time.

**NYSERDA Long Island solar + storage incentive** — A NYSERDA installation incentive that may apply to the energy storage component of paired solar + battery installations on Long Island. Eligibility and amount change; confirm with the program administrator.

**Carryforward** — The portion of a tax credit that cannot be used in the current tax year because it exceeds your tax liability, but can be applied to a future tax year. The New York Solar Equipment Credit allows up to a 5-year carryforward.

Equipment

**kW (kilowatt)** — A unit of power. Used to describe solar system size — a "9 kW system" produces up to 9 kilowatts of instantaneous power under ideal conditions.

**kWh (kilowatt-hour)** — A unit of energy. One kWh is one kilowatt of power flowing for one hour. Your PSEG bill measures usage in kWh; a typical Long Island home uses ~10,000–15,000 kWh per year.

**Module / Panel** — The physical solar panel that converts sunlight to electricity. Sized in watts (e.g., 400W per panel). A "9 kW system" typically uses 22–25 modules.

**Inverter** — Converts the DC electricity produced by solar panels into AC electricity that the home uses and the grid accepts. Two main types: string inverters and microinverters.

**Microinverter** — A small inverter mounted under each individual solar panel, converting DC to AC at the panel level. Adds shade-tolerance and per-panel monitoring; typically more expensive than string inverters but often preferred for Long Island homes with mixed roof exposure.

**String inverter** — A larger inverter that handles multiple panels in series (a "string"). Typically less expensive than microinverters but more sensitive to shade — partial shade on one panel can reduce output of the entire string.

**Racking** — The aluminum mounting hardware that attaches solar panels to the roof. Includes rails, brackets, fasteners, and flashing.

**Coastal-grade racking** — Racking specifically rated for coastal salt-air corrosion. Required (or strongly recommended) for Long Beach, Oceanside-southern, bayfront, and Sound-side properties.

**Backup loadcenter / Critical-loads panel** — A separate electrical panel installed when adding battery backup. Carries the circuits the battery is sized to back up during outages.

**Battery (home battery storage)** — A residential energy storage system that can store solar generation for later use and provide backup power during outages. Common LI options include Tesla Powerwall, Enphase IQ Battery, FranklinWH, and others.

Financing

**Cash purchase** — Homeowner pays for the system outright. Owns the equipment. Keeps any applicable state and federal incentives directly. Typically produces the cleanest payback math.

**$0-down solar loan** — A loan that finances 100% of system cost. Homeowner owns the equipment. Most products include a reamortization clause assuming a federal tax credit pays down a chunk of principal at month 18. With the federal credit sunset for 2026 installs, this assumption may not apply.

**Reamortization clause** — Loan structure that recalculates the monthly payment after a lump-sum principal payment (typically assumed to come from the federal tax credit). If the assumed lump sum does not arrive, the post-reamortization monthly payment may be higher than the original quote suggested.

**Dealer fee** — A fee built into the system price of $0-down solar loans, typically 15–25%+ of the cash-equivalent price. Usually disclosed if homeowners ask directly; not always visible on the headline quote.

**Lease** — Third-party leasing company owns the system; homeowner pays a fixed monthly lease payment (sometimes with an annual escalator). Leasing company keeps any tax incentives. Typically produces lower lifetime savings than ownership but no capital outlay.

**PPA (Power Purchase Agreement)** — Similar to a lease but the homeowner pays a per-kWh rate for the electricity produced rather than a fixed monthly lease payment. Owner is the third-party developer; homeowner buys the kilowatt-hours.

**Escalator clause** — A clause in some lease/PPA agreements that raises the monthly payment or per-kWh rate over time (e.g., 2.9% annual increase). Important to read before signing.

Installation process

**Site survey / Site assessment** — Initial physical visit by the installer to measure the roof, evaluate shade, inspect the electrical panel, and finalize the system design. Often the first installer touchpoint after a signed contract.

**Roof penetration** — A bolt or fastener that passes through the roof membrane to attach racking. Required for most roof types; ballasted (weight-only) racking is an alternative on flat commercial roofs.

**Main service panel / Electrical panel** — The 100A, 150A, or 200A panel where the home's electrical service originates. Many older Long Island homes have 100A panels that benefit from a 200A upgrade before adding battery storage or a Level 2 EV charger.

**Building permit** — Local town or village approval required before installation. On Long Island, residential solar permits go through the Town of Hempstead, Town of Oyster Bay, Town of Smithtown, etc., or the relevant Village for incorporated villages (Freeport, RVC, Garden City, Mineola, Patchogue Village, etc.).

**Electrical inspection** — A post-install inspection by a third-party electrical inspector who verifies the installation meets code. Required before utility interconnection.

**Critical-loads design** — A battery-backup configuration where only specific circuits (refrigerator, sump pump, well pump, lighting, key outlets) are backed up. Less expensive than whole-home backup.

**Whole-home backup** — A battery-backup configuration where the entire home electrical system runs from the battery during outages. More expensive; typically requires a larger battery or multi-battery system.

PSEG Long Island specifics

**PSEG Long Island** — The utility serving most of Long Island's residential electric customers. Operates net metering, Time-of-Day rate plans, and the Battery Storage Rewards program for residential solar customers.

**Battery Storage Rewards** — A PSEG Long Island program where participating residential battery storage customers receive payments via aggregators in exchange for grid-service performance during the May–September window. Specific terms depend on the aggregator.

**LIPA Dynamic Load Management** — A Long Island Power Authority program multifamily and certain commercial customers may participate in for load-management compensation. Not directly residential.

**Aggregator** — A third-party company that enrolls residential battery customers into utility-side programs (like PSEG Battery Storage Rewards) and operates the batteries collectively. Different aggregators accept new participants at different times.

**Daily service charge / Customer charge** — Fixed monthly fees on every PSEG Long Island residential bill that do NOT decrease with reduced usage. Solar does not offset these charges. Even with a properly-sized solar system, the homeowner still receives a monthly PSEG bill for these fees.

Common acronyms quick-reference

**PTO** — Permission to Operate (utility approval to energize the system)

**PV** — Photovoltaic (the technology that converts sunlight to electricity)

**kW** — Kilowatt (power)

**kWh** — Kilowatt-hour (energy)

**ITC** — Investment Tax Credit (federal)

**RCEC** — Residential Clean Energy Credit (the federal credit that sunset for 2026 installs)

**NYSERDA** — New York State Energy Research and Development Authority

**LIPA** — Long Island Power Authority

**TOU / TOD** — Time-of-Use / Time-of-Day (rate plan)

**PPA** — Power Purchase Agreement (financing structure)

**VNEM** — Virtual Net Metering

**CDG** — Community Distributed Generation

**HOA** — Homeowners Association

**ARC** — Architectural Review Committee

**Final note**: incentives change and eligibility varies. Confirm details with the program administrator and a qualified tax professional. This glossary is general information, not tax or legal advice.