ReNu's Solar Dictionary


# Solar Dictionary

3-Tab Shingles 3 tab is a type of shingle which features cutouts, otherwise known as tabs, that are made along their lower edge. This means that each shingle appears as three different pieces when it's installed to the roof, yet it's only one. 3-tab’s appear flat on the roof as compared to architecture shingles which look dimensional.

A Solar Dictionary

Accelerated Depreciation – a government tax deduction that applies the first five years after you install new solar panels. The amount of the tax savings varies by year, and is based on the size of the solar installation.

Alternating Current (AC) – electricity that switches the direction it travels in. In the US, the flow of electric current coming out of your wall changes direction once per second. So every minute, it changes direction 60 times. This is safer and more efficient than Direct Current (DC).

Ampere (amp)the unit for electric current, measuring flow of electrons over time.

Architectural Shinglesalso known as laminated or dimensional shingles, architectural roofing shingles are among the highest quality roofing products made. Traditionally, they are composed of a heavy fiberglass mat base and ceramic-coated mineral granules that are tightly embedded in carefully refined, water-resistant asphalt.

Array (solar array) – the layout/arrangement of all the solar panels in a solar system. Solar arrays can be mounted onto roofs or the ground.

Azimuth – the angle your solar panels face from a bird’s eye view. For example, a panel facing east has an azimuth of 90o. South is 180o, and West is 270o.

B – Solar Dictionary

Backsheet the "backside" of a solar panel. It protects the inner parts of a panel from moisture and UV light, which over time can reduce the efficiency of a panel. High quality backsheets are important in assuring your panels last through at least the 25-year warranty.

Base Chargesometimes called an administrative fee, should generate enough revenue to cover the fixed costs associated with operating your utility. This includes things like the customer's meter, the infrastructure necessary to provide service to the customer's location, and reading the meter each billing period.

Batteriessee Solar Battery

Building-Integrated Photo Voltaic (BIPV) a group of solar panels installed on a roof or perhaps a side wall, as opposed to on the ground. It is a solar array attached to the building.

Breakersee Circuit Breaker

Breaker Box see Electric Panel

Building Inspectionduring the course of a project the jurisdiction that has issued the building permit will, in most cases, require inspections throughout the course of the project. These inspections are called building inspections and are specific to what is being inspected.

C – Solar Dictionary

Cancellation Period see Right of Rescission

Cell (solar cell)each section of a solar panel that converts an amount of sunlight into energy. Solar cells are connected to make up a solar panel.

Central Invertersee Inverter

Circuit Breakeran automatic electrical switch designed to protect an electrical circuit from damage caused by excess current from an overload or short circuit. Its basic function is to interrupt the current flow after a fault is detected.

Conduit a tube or trough for protecting electric wiring.

Copper Indium Gallium Deselenide (CIGS) a newer type of "thin film" solar panel that gets better efficiency than other thin film panels.

Corrugated Metal Roofcorrugated galvanised iron (CGI) or steel is a building material composed of sheets of hot-dip galvanised mild steel, cold-rolled to produce a linear corrugated pattern in them.  For roofing purposes, the sheets are laid somewhat like tiles, with a lateral overlap of one and half corrugations, and a vertical overlap of about 150 millimeters (5.9 in), to provide for waterproofing. CGI is also a common construction material for industrial buildings throughout the world.

Crystalline Silicon (C-Si)a general term for the most common types of solar panels, which are made of silicon. See polycrystalline and monocrystalline for more details.

Currentthe flow of electrons. When sunlight hits a solar panel, it causes electrons to flow. This electric current gets turned into energy to power your home or business.

Cycle a battery term meaning one complete discharge and recharge of a battery. A solar battery "filled" up to its maximum capacity that gets used and then recharged by the sun has gone through one cycle.

D – Solar Dictionary

Distributionsee Electric Power Distribution

Direct Current (DC)electricity that flows in the same direction, continuously. Solar panels produce DC electricity. Batteries use DC as well.

Direct Normal Irradiance (DNI)the amount of sunlight that "hits" a location each day. This number helps solar installers predict how much energy you’ll get from your solar panels. In more technical language, this is the amount of solar energy that falls per square meter, per day at a specific location. For example, a DNI of 5 means 5 kiloWatt-hours of solar energy hits each square meter per day. A higher DNI means more energy.

Distributed Power Electronicsthis is a category the solar industry uses to include all microinverters and power optimizers.

E – Solar Dictionary

Electrical Gridthe local system of interconnected power lines and equipment that produce and distribute power to all the nearby users, including farms, homes, and businesses. Solar panels can be connected to the grid (on-grid) or completely separate from it (off-grid).

Electric Panela metal electrical service box that accepts the main power to the home and distributes electrical current to the various circuits within the home. The electrical panel may need to be upgraded for solar installation depending on how many breakers are open, the age of the panel, and other factors.

Electric Power Distributionthe final stage in the delivery of electric power; it carries electricity from the transmission system to individual consumers. Primary distribution lines carry this medium voltage power to distribution transformers located near the customer's premises.

Electric Power Generationthe process of generating electric power from sources of primary energy. For utilities in the electric power industry, it is the stage prior to its delivery to end users or its storage. Electricity is not freely available in nature, so it must be "produced".

Electric Power Transmissionthe process by which electricity is transported over long distances to consumers.

Emergency Shut Off / Rapid Shut DownRapid shut down devices shuts down the solar array as soon as it detects that the grid in the area is down or via a switch. Rapid shut down stops power from going onto the grid. This helps prevent linemen from getting hurt while trying to fix power-line issues.  Rapid shut down is a requirement in the electrical code.

Enphasea brand/manufacturer of micro inverters.

Ethylene Propylene Diene Terpolymer (EPDM)an extremely durable synthetic rubber roofing membrane widely used in low-slope buildings in the United States and worldwide. Its two primary ingredients, ethylene and propylene, are derived from oil and natural gas.

G – Solar Dictionary

Generation Attribute Tracking System (GATS) an independent, centralized generation registry and tracking service for both emissions data and renewable energy credits (SRECS). The system enables states to implement energy policies requiring renewable energy or setting emission-reporting requirements and provides a framework for a growing market for electricity from renewable sources. Also see PJM GATS.

Generationsee Electric Power Generation 

Ground-Based Solar Arraythe alternative to installation panels on your roof. A ground-based array usually sits on poles of racks near the buildings for which they provide power.

Grid-Connected Systemsee On-Grid

H – Solar Dictionary

Home Improvement Contract (HIC) – an agreement between the contractor and homeowner that contains all of the terms of the improvement project. Home improvement contracts must adhere to the applicable state laws and spell out each party's responsibilities in detail.

I – Solar Dictionary

Inspection see Building Inspection

Interconnection Agreement a legal contract between the electric utility and the customer allows the customer to connect to the electric grid.

Inverteralso known as a central inverter; is a required part of any solar system. The inverter makes the energy collected by solar panels usable by your home. In more technical language, the inverter converts direct current (DC) from the solar panels into the alternating current (AC) that your power outlets can use.

Inverter Efficiencyhow well your inverter turns DC into AC without losing too much energy. Small losses here can add up to big money lost over the 25-year lifespan of your solar panels.

Investment Tax Credit (ITC) a federal tax incentive for installing solar panels. Right now, the ITC gives you a 26% total credit for the entire solar installation process for the 2022 year. Any changes to this percentage would come from new laws.

K – Solar Dictionary

Kilowatts (kW) – a unit of power equal to
1,000 watts (see Watts). It's also the performance metric used to describe a solar system. For example, a 5kW solar system will produce 5kW of energy per hour of direct sunlight. So if the solar system had 5 hours of direct sunlight per day, it would produce 25kW per day.

Kilowatt-hours (kWh) – the amount of kilowatts produced or used per hour. You can see this unit on your monthly electric bill to see how much energy you’re currently using.

L – Solar Dictionary

Lease is a type of Third-Party Ownership (TPO) financing model. The system is not owned by the homeowner but instead leased out by the solar company who installed it.

Loan similar to a home improvement loan, the homeowner borrows money from a lender, either a bank or a solar company, and then pay it back with interest through monthly installments. 

M Solar Dictionary

Megawatts a unit of power equal to 1,000 kilowatts (also see Watts).

Metersee Utility Meter and Net Metering

Meter Basean enclosure that protects an electric meter from the elements, keeping wires and electrical connections dry. A home's meter base may need to be upgraded to meet greater power demands and promote safety.

Microinverter does what an inverter does, but for each solar panel rather than the whole system. A microinverter turns the solar energy from each panel into energy that your home can use. They are similar to power optimizers in their purpose - to reduce energy losses from factors like the shade, soiling, and parts of a panel that stop working.

Mismatchwhen one part of a solar panel produces a different amount of energy than another part. This condition reduces the efficiency of the whole panel and can be prevented by using microinverters and power optimizers.

Module (solar module)another word for a solar panel.

Monocrystalline Siliconone of the most common types of solar panels. Made of silicon, these crystalline panels are one of the most durable and efficient solar panels available in the market today. They are a single crystal of silicon and usually look like circular cells in the solar panel.

N – Solar Dictionary

Net Meteringan agreement with your utility company that allows you to "sell" your excess solar energy to them, and lets them charge you for any energy you use that wasn't produced by your solar system. It’s a partnership that keeps you connected to the grid and assures you of steady power
* not all states allow net metering

O – Solar Dictionary

On-Gridsolar systems that are connected to the power grid. This means your utility company can still supply you energy if your solar panels don’t produce enough. It also means you can produce excess energy, and if allowed, sell it to the utility company.

Off-Gridsolar systems that are not connected to the power grid. Cut ties with your utility company and gain true energy independence with an off-grid solar system.

Ownershipcustomers can own their solar system through cash or loan.

P – Solar Dictionary

Peak Shavingreducing how much energy you use during "peak" hours, when utility companies tend to charge higher prices. Peak hours are usually from 12pm - 6pm.  

Pennaepsallows you to sell on the Pennsylvania open SREC market. Pennaeps requires a PJM number and registration.

Permission to Operate (PTO) – a written authorization, from the local electric utility (utility company), to interconnect a solar system to the local electrical grid.

Permitsbefore a solar system can be installed on a property, the system owner must meet a variety of permitting requirements. Depending on the state, local government, type and size of the system, the permitting process could require significant time and costs.

Photo Voltaic (PV) scientific term used to describe how solar panels turn sunlight into energy. "Photo" refers to photons (packets of light that hit a surface). "Voltaic" refers to voltage and electricity (which is what the solar energy becomes). PV is also the industry term used for solar panels, and it's commonly used in the place of "solar" (ie: PV panels, PV cells, PV modules, PV array).

PJMa regional transmission organization (RTO) that coordinates the movement of wholesale electricity. They're also the credit registration that issues alternative energy credits.

PJM Generation Attribute Tracking System (GATS)a trading platform to buy and sell renewable energy certificates (RECS) - each certificate represents one megawatt-hour of electricity produced. PJM provides the generation data (from a registered system) for GATS to track and record.

Polycrystalline Siliconthe most common type of solar panel. Made of silicon (small bits of crushed up silicon crystals), polycrystalline panels offer efficiency, durability and reliability.

Power Optimizeran add-on component to solar panels that boosts efficiency and helps reduce the power lost from obstructions (ie: shading, soiling, debris, leaves) and the damaged parts of a panel that stop working.

Power Purchase Agreement (PPA)also known as electricity power agreement, is a contract between two parties, one which generates electricity (the seller) and one which is looking to purchase electricity (the buyer). The PPA defines all of the commercial terms for the sale of electricity between the two parties, including when the project will begin commercial operation, schedule for delivery of electricity, penalties for under delivery, payment terms, and termination. A PPA is the principal agreement that defines the revenue and credit quality of a generating project and is thus a key instrument of project finance. There are many forms of PPA in use today and they vary according to the needs of buyers, sellers, and financing counter parties.

R – Solar Dictionary

Rackingwhat solar panels are placed on when installed on a roof. The racks are bolted to the roof, and the panels are connected to the racks. Different types of racking, and the space between the racks, may be necessary depending on the type of roof and other factors.

REAP Grant (Rural Energy for America Program)a grant that is available to certain farms, agricultural, and other rural businesses that make energy improvements, including solar panels. The grant will cover up to 25% of solar installation costs for qualified applicants.

REAP Loan like the grant, this is a loan meant to accomplish the same goals, except you do have to pay it back. But it makes the initial installation far more affordable. Both the loan and the grant are exceptional opportunities for farms and agricultural businesses looking to go solar.

Right to Rescindalso known as the right of rescission, created by the Federal Truth in Lending Act, gives homeowners the absolute right to cancel a home improvement contract, usually until midnight of the third day after closing (the cancellation period), excluding federal holidays and Sundays.

Return on Investment (ROI)a ratio between net profit and cost of investment. A high ROI means the investment's gains compare favorably to its cost. As a performance measure, ROI is used to evaluate the efficiency of an investment or to compare the efficiencies of several different investments.

Roof Flashinga thin material (usually galvanized steel), that professional roofers use to direct water away from critical areas of the roof. The critical areas are typically wherever the roof plane meets a vertical surface, like a wall or a dormer. Flashing is installed to surround roof features, such as vents, chimneys and skylights.

Roof Planea roofing area defined by having four separate edges. One side of a gable, hip or mansard roof.

Rubber Roofsee EPDM

S – Solar Dictionary

Schedule Aa PJM document stating that the generation-owner gives you their consent to operate on their behalf within the GATS system.

Shadingwhen all or part of your solar panels are covered by a shadow. Shading reduces the energy a solar panel can collect.

Shingles (roof shingles)a roof covering consisting of individual overlapping elements. These elements are typically flat, rectangular shapes laid in courses from the bottom edge of the roof up, with each successive course overlapping the joints below. 

Site Surveyinspections of an area where work is proposed, to gather information for a design or an estimate to complete the initial tasks required for an outdoor activity. It can determine a precise location, access, best orientation for the site and the location of obstacles.

Solar Arraysee Array

Solar Batterystores excess solar energy. If your panels collect more energy than you use, then it'll either get wasted or sent to the electric grid. Solar batteries make it possible to use all of your solar energy - even at night! Plus, you can store and save any excess energy for the colder and darker winter months.

Solar Cellsee Cell

Solar Energyany energy collected from the sun. The solar industry is humanity’s attempt to do the same thing - collect and use the energy from the sun for our power and electric needs.

Solar Farma large-scale collection of solar panels. They're typically mounted to the ground and use lots (parking lots) of acreage. They are usually owned by regional power companies, or very large private companies with massive power needs.

Solar Panelthe commonly seen rectangular flat sheets that connect together and collect energy.

Solar Renewable Energy Credits (SRECs)a form of renewable energy certificate or "green tag" existing in the U.S. SRECs exist in states that have Renewable Portfolio Standard (RPS) legislation with specific requirements for solar energy, usually referred to as a "solar carve-out". The additional income from selling SRECs, increases the economic value of a solar investment and assists with the financing of solar technology. In conjunction with state and federal incentives, system owners can recover their investment in solar by selling their SRECs through spot market or long-term sales.

Soilingthe collection of dust and debris on your solar panels, which prevents the sunlight from impacting those sections of the panel. You can prevent solar efficiency losses from soiling by regular cleaning and maintenance.

Standing Seam Roof a concealed fastener, metal panel system that features vertical legs and a broad, flat area between the two legs. Standing seam systems can be used for either metal roofing (the most common) or metal walls.

String Invertera device used with solar arrays to convert the energy that is generated (direct current) to usable electricity for a home (alternating current). They are connected to multiple solar panels forcing the performance to be equal to the worst performing panel.

System Lossesany losses of energy from what was originally collected from the sun by your solar panels. Losses can happen in all sorts of ways, many of them unpreventable, but some can be reduced - such as shading.

T – Solar Dictionary

Thin-Filma certain type of solar technology that is much thinner than the most common crystalline types. Thin film is less efficient, but also less costly.

Tilt the angle of your solar panels compared to the ground, not your roof. A 90o tilt means the panel stands up vertically. Typical tilts are between 20o – 40o, though there are many factors that affect this, with the main one being your roof.

Tracker solar panels equipped to adjust their position based on the sun's movements. They "track" the sun’s position as it changes by the day and season. These panels get more direct sunlight which produces much more energy. There are two types of trackers available; the ones that only adjust on one axis and those that adjust on two (vertical and horizontal).

Transmissionsee Electric Power Transmission

U – Solar Dictionary

Ultraviolet (UV) Lightthe sun’s visible light is only one portion of the radiation it produces. UV is an unseen part of the sun’s energy, but it still affects solar panels.

Utility Meter the metering (measuring) devices used on utility mains. The most common metering devices are the electric and smart meters. The electric meter measures electricity usage, and the smart meter measures electricity consumption. Smart meters also communicate their data to the utility company for monitoring and billing.

V – Solar Dictionary

Voltagethe "force" required to move electrons. Without voltage, there is no current. Without current, there is no electricity.

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