Solar Glossary

Jump to section: Solar Terms | Solar Financial Glossary Solar Terms Absorption Chiller – A device that uses themal (solar) energy to cool and dehumidify air. AC (Alternating Current) – Standard method of current used by most applicances and buildings. Amps – Unit used to measure electrical current. Array – A group of PV modules used to power a solar system. Amorphous Silicon (a-Si) – A thin-film, silicon photovoltaic cell having no crystalline structure. The material of FlexLight laminates, which convert sunlight into electrical energy. Balance of Systems (BOS) – Parts of a photovoltaic system excluding the array (i.e. inverter, wiring, disconnects, batteries, etc.). Battery Backup System – A photovoltaic system in which batteries are used to store power for later use. Battery Energy Capacity — The total energy available, expressed in watt-hours (or kilowatt-hours), which can be withdrawn from a fully charged battery.  Capacity varies in terms of temperature, rate, age, and cut-off voltage. Building Energy Code – The code that establishes minimum energy performance features in buildings. Building-Intergrated PV – The integration of standard photovoltiac modules, transparent modules, and thin-film covers into conventional building materials such as roofs, walls, facades, awnings, and skylights. These materials generate electricity from sunlight and perform other functions integral to the design of the building. British Thermal Units (BTU) – Standard unit of heat measurement used in heating and air conditioning applications. Crystalline Silicon (c-Si) – The material used in crystalline modules to convert sunlight into electricity. Code Official – A local government employee who enforces codes and standards, ensuring that solar energy system installations meet applicable safety, building, electrical and plumbing codes held in a region. Commercial Energy Conservation Ordinance (CECO) – A CECO requires commercial property owners to complete certain energy conservation measures in their buildings upon transfer of property ownership or when additions or renovations are made. Concentrated Solar – A type of solar power that uses lenses, mirrors, and a tracking system to focus large areas of sunlight into a concentrated beam. The concentrated sunlight is then captured for themal or photovoltaic use. Conductor — Material through which electricity is transmitted, such as an electrical wire, or transmission or distribution line. Bypass Diode – An electrical device that ensures power output even when a part of a photovoltaic panel or module is shaded. Daylighting – Using natural sunlight or concentrated sunlight with fiber optics to light interior spaces. Direct Current (DC) – Standard method of current delivery used by most photovoltacis systems. Dual Axis Tracking – A method of array mounting that follows sunlight in both the North/South and East/West directions. Flat Panel Collector – A solar water heater consisting of a thin absorber sheet (ususally painted black) , backed by a grid or coils of fluid tubing contained in a case with a glass or polycarbonate cover Emissions – In the context of global climate change, emissions refer to a release of greenhouse gases into the atmosphere, such as CO², methane, and oxides of nitrogen. Evacuated Tube Collector – Solar hot water heater consisting of a series of modular tubes Grid - A system of high tension cables in a region that distributes electricity to homes, businesses and other buildings. Grid Connected – A photovoltaic system that is connected to the electrical utility usually without the use of batteries. Ground Mount - A solar electrical system that is mounted on the ground instead of on a roof. High Efficiency PV Cell – Cells with 35% efficiency or greater. Hybrid System — A solar electric or photovoltaic system that includes other sources of electricity generation, such as wind or diesel generators. Inverter – A device that converts DC electricity from a PV system into usable AC electricity. Leadership in Energy and Environmental Design (LEED) - A voluntary, consensus-based national rating system for developing high-performance, sustainable buildings operated by the U.S. Green Building Council. Load – Describes the amount of power, expressed in amps, consumed by an electrical circuit or device. Lumens – A unit of measurement for the intensity of light. Modular Solar System – A solar electric or thermal system in which individual components may be added or taken away to customize the size for desired applications. Net Metering – A billing mechanism that credits solar system owners for the electricity exported onto the electricity grid. Under the simplest implementation of net metering, a utility customer’s billing meter runs backward as solar electricity is generated and exported to the electricity grid and forward as electricity is consumed from the grid. Property Tax Incentive – An exemption, abatement, or credit that mitigates or eliminates the increase in taxes owed resulting from an increase in assessed value of a property due to the added value from solar energy installations, providing an additional incentive to invest in a solar installation. Photovoltaic Power (PV) – Process by which energy from the sun is converted to electrical energy. PV Cell – Portion of a PV module or laminate that converts sunlight to electricity. One PV module or laminate has many PV cells. PV Laminate (PVL) – Photovoltaic device consisting of amorphous silicon cells, wiring, and an encasement. PV Module – Photovoltaic device consisting of crystalline silicon PV cells, wiring, and an encasement. Sales Tax Incentive – Exemption from or refund of sales tax for purchasing and installing solar energy components and systems. Solar Power – Energy which is derived from the sun (i.e. photovoltaic, solar thermal). Solar Thermal – A process by which the sun’s energy is harnessed and used to heat a high temperature liquid, usually for commercial applications. Solar Hot Water – the process of using power from the sun for heating applications (hot water, cooling, steam, etc.) usually in residential applications. Thin Film – A type of solar panel which is manufactured with a minimal amount of material. As a result these panels can be flexible. Tilt Angle — Angle at which a photovoltaic array is set to face the sun relative to a horizontal position, can be set or adjusted to maximize seasonal or annual energy collection. Voltage – Unit of measurement used to determine portential difference in electrical devices. Watt (W) – A unit of electricity that measures the electrical power produced.  1000 watts (W) = 1 kilowatt (kW) Watt-hour (Wh) – A unit of electricity that measures energy production over time. 1000 (Wh) = 1 kilowatt (kWh)     Solar Financial Glossary Alternative Compliance Payment – In lieu of standard means of compliance with renewable portfolio standards, electricity suppliers may make alternative compliance payments to make up for deficiencies (in megawatt-hours) between the amout of electricity from renewable resources mandated and the amount actually supplied. Payment amount varies among states. Accelerated Depreciation – The Internal Revenue Code permits depreciation of a solar asset over a shorter time period than some other assets. Bonus Depreciation – The Internal Revenue Code allows additional depreciation in the first year for solar assets. Break Even Year – The year in which the original cost of a solar system is fully recovered by the purchaser. Buy-Down – A reduction in costs to purchasers. Cash Flow – Dollars going in or out based on revenues or expenses. Clean Renewable Energy Bond (CREB) – Special-purpose tax credit bonds that provide the equivalent of an interest-free loan for certain qualifying energy facilities. Bondholders receive a tax credit on their federal income taxes instead of an interest payment from the bond issuer. Cumulative Cash Flow – The sum of dollars going in or out based on revenues or expenses over time. Customer Aggregation Program – A program that coordinates group purchases of solar energy systems, helping defray some of the up-front costs of solar installations by giving aggregated individuals of businesses a discounted rate for bulk purchases of solar energy systems. Depreciation – Recapture of the original cost of an asset taken in the form of an income tax deduction. Depreciation lowers a company’s reported earnings resulting in tax savings. Direct Incentive- Cash back to customers for a qualified solar installation. Direct incentives include up-front rebates and grants and production-based incentives that are typically distributed over several years. Efficiency Factor – The factor used to calculate the amount of electricity produced by a solar system. Includes assumptions on electricity per sun hour, inverter losses, line losses, etc. Environmental Offset – The positive environmental impact of solar power can be equated to traditional commodities. For example, a 100 kW solar system offsets just under 10,000 gallons of gasoline every year. Energy Audit- A survey that determines how much energy is used in a home, which helps identify ways to use less energy. Energy Payback Time- Time required for any energy producing system or device to produce as much energy as was required in its manufacture. Expected Performance Rebate- Cash incentive based on the expected energy output from a solar energy system over a given period of time. Feed-in tariff (FIT) – A renewable energy supply policy that offers a guarantee of payment over a fixed amount of time, usually ten to twenty years, to renewable energy developers for the electricity they produce. Greenhouse Gas – Atmospheric gases that absorb and emit radiation. Common greenhouse gases in the earth’s atmosphere include water vaper, carbon dioxide, methane, oxides of nitrogen, ozone, and chlorofluorocarbons. Greenhouse Gas Credit – Unit of measure for the value of a unit of greenhouse gas averted. The value of a Credit is determined by the local or legislated market. Green Pricing – A mechanism for utility customers to support their utility’s inventments in renewable energy projects through direct charges on their monthly utility bills. Green pricing is a market-based solution to account for the nonmarket benefits of renewable energy. Internal Rate of Return (IRR) – Method for comparing the value of investments. If the return on a solar system exceeds your return on other investments, then the solar system is a more lucrative option. Loan to Value (L/V) – The ratio of the cost of a solar system paid in cash to the amount borrowed. If you put 25% down and borrow 75% of the cost of the system, then the L/V = 75%. Net Present Value (NPV) – The value today of an investment’s future net cash flows discounted by the assumed interest rate and risk of the investment. Power Purchase Agreement (PPA) – Contract to purchase electricity at a set price over a predetermined period of time. Used to purchase electricity from a solar system. Renewable Energy Certificate (REC) – unit of measure for the value of a unit of electricity produced from a renewable resource. Most often 1 MWh = 1 REC. The value of a REC is detemined by the local or legislated market. Return on Investment (ROI) – Income that an investment provides at the end of a period of time. Tax Credit – Payment from a government to a solar system owner as an incentive to purchase. A purchaser can only take a tax credit if they have tax liability. Tax Effect – Amount by which you reduce the value of an income stream due to required tax payments.