Solar Energy Glossary

ALMM stands for Approved List of Models and Manufacturers. It is an MNRE framework covering eligible solar photovoltaic models and manufacturers. MNRE states that modules included in the applicable ALMM List-I are eligible for specified government projects, government-assisted projects, government schemes and certain open-access and net-metering projects. The lists are periodically updated.

Battery backup allows a solar system or electrical installation to supply stored electricity when solar generation is unavailable or when grid power is interrupted. Battery backup requirements depend on the appliances to be powered, their load, required backup duration, and battery capacity.

A Battery Energy Storage System (BESS) stores electricity in batteries and makes it available when required. A BESS typically includes batteries, a battery management system, power-conversion equipment, controls and safety systems. BESS solutions are used in residential, commercial, industrial and grid-scale energy applications.

A Battery Management System (BMS) is an electronic system that monitors and manages battery operation. It can monitor parameters such as voltage, temperature and state of charge while providing protection against unsafe operating conditions. BMS technology is particularly important in lithium battery energy-storage systems.

Battery storage stores electrical energy for use at a later time. In solar systems, batteries can store surplus solar generation during the day and supply electricity when solar production is low or unavailable. Battery storage is useful for backup power and, depending on the system design, energy management.

A bidirectional meter measures electricity flowing in both directions between a property and the electricity grid. In a grid-connected solar system, it can record electricity imported from the grid and electricity exported from the solar installation. The exact metering arrangement depends on the applicable regulations and DISCOM requirements.

A bifacial solar panel can generate electricity from light received on both its front and rear surfaces. Rear-side generation can increase energy yield when the installation allows sufficient reflected or diffused light to reach the back of the module. Performance depends on factors such as mounting height, ground reflectivity and installation design.

The CAPEX solar model is a solar ownership model in which the customer pays the upfront capital expenditure to purchase and install the solar system. The customer typically owns the system and receives the economic benefits from electricity generation. The model requires higher initial investment but provides direct ownership of the solar asset.

A charge controller regulates electricity flowing from solar panels to a battery. It helps manage battery charging and protects the battery from conditions such as overcharging. Common technologies include PWM and MPPT charge controllers.

Commercial solar refers to solar power systems installed for businesses such as offices, retail facilities, warehouses, hotels, schools and other commercial properties. Commercial solar can help businesses generate electricity on-site and manage energy costs. System size and design depend on electricity consumption, roof area and operating requirements.

A commercial solar system is a solar installation designed to meet the electricity requirements of a business or commercial facility. It can be installed on rooftops, parking structures or available land. System capacity is generally determined by electricity consumption, available space, operating hours and project economics.

DCR solar module generally refers to a solar PV module meeting applicable Domestic Content Requirement conditions under a government programme or scheme. DCR requirements can specify domestic manufacturing or sourcing conditions for eligible components. Applicability depends on the particular government programme and its current guidelines.

DISCOM stands for Distribution Company or electricity distribution company. A DISCOM supplies electricity to consumers within a designated service area and manages distribution-related services. For grid-connected rooftop solar, the DISCOM may be involved in application processing, inspection, meter-related processes and grid connection according to applicable rules.

Gross metering is a grid-connected solar arrangement in which electricity generated by a solar system is measured separately and supplied to the grid under the applicable regulatory and commercial framework. Unlike net metering, generation and consumption may be accounted for separately according to the relevant state policy or electricity regulations.

Home solar cost is the total expense of installing a solar power system for residential property. It may include solar panels, inverter, mounting structure, cables, protection devices, installation, net-metering-related charges, and batteries if required. The final cost depends on system capacity, technology, location, installation conditions, and applicable subsidy or financing.

A home solar system is a residential solar installation designed to generate electricity for household use. It may include solar panels, an inverter, mounting structure, protection equipment, a meter and optional battery storage. Home solar systems can be grid-connected, off-grid or hybrid.

A hybrid inverter combines inverter and energy-management functions for systems that can use solar panels, the electricity grid and batteries. It can convert solar DC electricity into AC electricity and manage battery charging and discharging. Hybrid inverters are commonly used in solar systems requiring both grid connectivity and backup.

A hybrid solar system combines solar panels, battery storage and grid connectivity. It can use solar electricity for loads, store surplus energy in batteries and draw electricity from the grid when required. Hybrid systems are suitable for users who want both solar generation and backup capability.

Industrial solar refers to solar power systems designed for industrial facilities such as factories, manufacturing units, warehouses and processing plants. Industrial solar can be installed on rooftops, carports or ground-mounted structures. System design typically considers high electricity demand, operating hours, available space and electrical infrastructure.

An industrial solar system is a solar PV installation designed for factories, manufacturing plants, warehouses and other industrial facilities. It may be rooftop-mounted, ground-mounted or installed on another suitable structure. The design considers energy demand, load profile, available space, electrical infrastructure and the facility's operating schedule.

A kilowatt hour (kWh) is a unit of electrical energy. One kWh represents the amount of energy consumed or generated when a 1-kilowatt load operates for one hour. Electricity bills are commonly measured in kWh. Solar generation and battery storage capacity can also be discussed using kWh.

A LiFePO4 battery, or lithium iron phosphate battery, is a type of lithium-ion battery commonly used for energy storage. It is known for its long cycle life, thermal stability and suitability for repeated charging and discharging. LiFePO4 batteries are used in residential, commercial and off-grid solar applications.

MNRE stands for the Ministry of New and Renewable Energy, Government of India. It is the central ministry responsible for developing and promoting renewable energy in India, including solar, wind, bioenergy and other renewable-energy technologies. MNRE publishes policies, guidelines, programmes and technical requirements related to renewable energy.

A monocrystalline solar panel is made using solar cells manufactured from monocrystalline silicon. These panels are generally known for high efficiency and a relatively uniform appearance. Their suitability depends on factors such as available roof space, budget, power requirements and desired system performance.

MPPT, or Maximum Power Point Tracking, is a technology used by solar inverters and charge controllers to extract available power from solar panels efficiently. MPPT continuously adjusts the electrical operating point of the PV array according to changing sunlight and operating conditions.

An MPPT charge controller uses Maximum Power Point Tracking to optimize the electrical operating point of a solar array and transfer available solar energy efficiently to a battery. Compared with basic charge-control methods, MPPT technology can provide better energy harvesting under varying voltage and environmental conditions.

An N-type solar panel uses solar cells based on an n-type silicon wafer. N-type cell technologies include TOPCon and other advanced cell architectures. These technologies can offer high efficiency and improved resistance to certain degradation mechanisms, depending on the specific cell and module design.

A net meter is a bidirectional electricity meter used in eligible grid-connected solar systems to measure electricity flowing between a consumer's premises and the electricity grid. It can record electricity imported from and exported to the grid according to the applicable metering arrangement and local regulations.

Net metering is a billing arrangement in which electricity generated by a grid-connected rooftop solar system can be consumed on-site, while eligible surplus electricity can be exported to the grid through an appropriate meter. The treatment of exported electricity depends on the applicable state regulations and DISCOM rules.

An off-grid inverter converts electricity stored in batteries or generated by solar panels into AC electricity for appliances without relying on the utility grid. It is designed to manage independent power systems and is commonly used in remote locations, backup applications and standalone solar installations.

An off-grid solar system operates independently of the electricity grid. It typically includes solar panels, batteries, a charge controller or hybrid inverter and other electrical components. Off-grid systems are useful in locations where grid electricity is unavailable, unreliable or not economically practical to connect.

An on-grid inverter converts DC electricity from solar panels into AC electricity and synchronizes the output with the electricity grid. It is designed for grid-connected solar systems and generally operates with grid availability. The specific protection and grid-support features depend on the inverter model and applicable standards.

An on-grid solar system is connected to the electricity grid. Solar panels generate electricity for on-site consumption, while electricity can be imported from the grid when solar generation is insufficient. Depending on applicable regulations and the metering arrangement, eligible surplus generation may be exported to the grid.

Open access solar allows eligible electricity consumers to obtain renewable electricity from a generating source through the electricity transmission or distribution network, subject to applicable regulations and charges. Open-access solar is commonly considered by larger commercial and industrial consumers seeking renewable electricity without necessarily installing the entire generation system at their own premises.

The OPEX solar model is a solar financing or ownership arrangement in which a third party typically invests in and operates the solar system, while the customer pays for the electricity generated under an agreed commercial arrangement. PPAs are a common example of an OPEX-style solar model.

Photovoltaic (PV) refers to the technology that converts light directly into electricity using semiconductor materials. Solar cells use the photovoltaic effect to generate DC electricity when exposed to sunlight. PV technology is widely used in rooftop solar systems, commercial projects and large solar power plants.

PM Surya Ghar refers to the PM Surya Ghar: Muft Bijli Yojana, a Government of India rooftop solar programme focused on supporting residential consumers in installing rooftop solar systems. The scheme provides Central Financial Assistance for eligible residential installations through the national portal and applicable implementation guidelines.

A polycrystalline solar panel uses solar cells made from multiple silicon crystal structures. Polycrystalline technology has historically been used for cost-focused solar installations. Today, buyers should compare panel efficiency, warranty, degradation characteristics, technology and total system economics rather than selecting a panel solely by cell type.

A Power Purchase Agreement (PPA) is a contractual arrangement under which electricity is supplied by a power producer to a buyer for an agreed period and under defined commercial terms. Solar PPAs are commonly used in commercial and industrial renewable-energy projects where electricity is purchased from a solar project.

A pure sine wave inverter produces an AC waveform that closely matches the electricity supplied by the utility grid. It is suitable for many household appliances, electronics, motors and sensitive equipment. Pure sine wave inverters are commonly used in residential backup and off-grid solar systems.

Renewable energy comes from naturally replenishing sources such as sunlight, wind, water and biomass. Solar energy is one of the most widely used renewable energy sources for electricity generation. Unlike fossil fuels, renewable energy sources can provide electricity without depending on the combustion of coal, oil or natural gas.

Residential solar subsidy refers to government financial assistance available to eligible households installing solar systems. Under PM Surya Ghar, Central Financial Assistance is available for eligible residential rooftop solar systems according to the applicable scheme structure and guidelines. Consumers should verify the current subsidy rules before installation.

A residential solar system is a solar PV installation designed to generate electricity for a home. It can include solar panels, an inverter, mounting structure, electrical protection, metering equipment and optional batteries. Residential systems may be on-grid, off-grid or hybrid depending on the homeowner's electricity and backup requirements.

Rooftop solar is a solar power system installed on the roof of a home, commercial building, institution, or industrial facility. Rooftop solar panels generate electricity close to where it is consumed. Depending on the configuration, the system may be connected to the electricity grid, including battery storage, or operating independently.

Rooftop solar subsidy refers to financial assistance that may be available for eligible rooftop solar installations. In India, residential consumers can access applicable Central Financial Assistance under programmes such as PM Surya Ghar, subject to scheme rules and eligibility. State-level incentives may also apply separately.

A rooftop solar system is a photovoltaic system installed on the roof of a residential, commercial, institutional or industrial building. It typically includes solar modules, an inverter, mounting structures and electrical protection equipment. Depending on the design, it can operate with the grid, batteries or both.

A 1 kW solar system has a nominal solar capacity of 1 kilowatt. It is generally suitable for relatively low electricity consumption or smaller applications, depending on the location and energy requirements. Actual generation varies according to sunlight, system orientation, shading and equipment efficiency.

A 10 kW solar system has a nominal solar capacity of 10 kilowatts. It is commonly used for larger residential properties, commercial buildings, offices, institutions and small industrial applications. The required system capacity should be determined using electricity consumption data and available installation space.

A 2 kW solar system has a nominal solar generation capacity of 2 kilowatts. It may be suitable for households with relatively moderate electricity consumption, depending on local solar conditions and daily energy requirements. Actual generation varies by location, sunlight and system design.

A 3-kW solar system has a nominal solar generation capacity of 3 kilowatts. It is commonly considered for residential properties with moderate electricity consumption. Actual electricity generation depends on sunlight, location, panel orientation, shading, system efficiency, and weather conditions.

A 5 kW solar system has a nominal generation capacity of 5 kilowatts and is commonly considered for larger residential properties, small commercial premises and other applications with higher electricity consumption. The appropriate system size depends on electricity usage, available roof space and local conditions.

A smart meter is an advanced electricity meter that can digitally record electricity consumption and, depending on the system, support communication with the utility. Smart meters can provide more detailed consumption information and support modern electricity-grid management. Their exact features depend on the electricity distribution company and applicable regulations.

A solar battery stores electricity generated by solar panels so it can be used later. Solar batteries are particularly useful for backup power and for storing excess solar generation. Common battery technologies include lithium-ion, LiFePO4, and lead-acid batteries. Battery capacity is generally measured in kWh.

A solar cell is the basic electricity-generating component of a photovoltaic module. It converts sunlight into DC electricity using semiconductor materials. Multiple solar cells are electrically connected and packaged together to create a solar module or solar panel.

A solar charge controller manages electricity from solar panels going into a battery. It regulates the charging process and helps protect the battery from overcharging and other operating conditions. PWM and MPPT are two common types of solar charge controllers.

Solar EMI is the periodic payment made toward a loan used to finance a solar power system. The EMI generally depends on the financed amount, interest rate and loan tenure. Customers should compare the total repayment amount, processing fees and other charges rather than considering EMI alone.

Solar energy is energy obtained from sunlight and used to generate electricity or heat. Solar photovoltaic systems convert sunlight directly into electricity, while solar thermal systems use sunlight to produce heat. Solar energy is renewable because sunlight is naturally replenished and can be used for residential, commercial, and industrial applications.

Solar EPC stands for Engineering, Procurement and Construction. A solar EPC company can manage the engineering and system design, procurement of equipment and construction or installation of a solar project. EPC services are widely used for commercial, industrial and large-scale solar installations.

Solar financing refers to financial solutions used to fund the purchase and installation of solar systems. Options can include solar loans, equipment financing, leases, PPAs and other structured financing models. The most suitable option depends on project size, ownership preference, cash flow and financing terms.

Solar for business means using solar power to generate electricity for commercial operations. Businesses can install rooftop or ground-mounted solar systems or use other renewable-energy procurement models. Solar can help businesses reduce dependence on grid electricity and increase renewable-energy usage, subject to site conditions and applicable regulations.

Solar for factory refers to using photovoltaic systems to generate electricity for manufacturing and industrial operations. Factories may install rooftop, ground-mounted or other solar systems depending on available space and electrical requirements. Solar generation can be used for on-site consumption or supplied through applicable grid arrangements.

Solar for home refers to using photovoltaic technology to generate electricity for residential consumption. Home solar systems can reduce dependence on grid electricity and may support backup or energy storage when batteries are included. System size should be selected based on electricity usage, roof area, and local solar conditions.

Solar installation is the process of setting up a solar power system at a residential, commercial, or industrial site. It generally includes site assessment, system design, mounting structure installation, panel installation, inverter installation, electrical connections, testing, and commissioning.

A solar inverter converts DC electricity produced by solar panels into AC electricity that can be used by household or commercial appliances. Depending on the system, an inverter can also manage grid interaction, battery charging, monitoring, and protection. Common types include on-grid, off-grid, and hybrid inverters.

A solar loan is financing used to pay for a solar power system. Depending on the lender and product, the loan may cover equipment, installation or the complete project. Interest rate, tenure, processing fees, down payment and eligibility vary between financial institutions.

A solar module is an assembled unit containing interconnected photovoltaic solar cells protected by materials such as glass, encapsulant, and a backsheet or glass structure. Solar modules are commonly referred to as solar panels in everyday usage. Module specifications include power rating, efficiency, voltage, current, and dimensions.

A solar mounting structure is the framework used to securely install solar panels on rooftops, ground surfaces or other structures. It maintains the required panel orientation and tilt while providing structural support. Mounting systems may be made from materials such as galvanized steel or aluminium.

Solar net metering is a grid-connected electricity billing mechanism that measures electricity imported from and exported to the grid. A rooftop solar consumer can use solar power locally and, where permitted, export eligible excess generation. The exact settlement mechanism depends on the applicable state electricity regulations and DISCOM.

A solar panel is a device made up of multiple solar cells that convert sunlight into electricity through the photovoltaic effect. Solar panels are commonly installed on rooftops, commercial buildings, factories, and solar plants. The electricity generated can be used directly, stored in batteries,, or supplied to the electricity grid depending on the solar system configuration.

Solar panel cleaning involves removing dust, dirt, bird droppings and other deposits from photovoltaic modules. Regular cleaning can help maintain panel performance, particularly in locations with high dust or pollution. Cleaning frequency should depend on local environmental conditions and manufacturer recommendations.

Solar panel efficiency indicates how effectively a solar module converts incident sunlight into electricity under specified test conditions. A higher-efficiency panel can produce more power from a given area, which can be particularly useful when rooftop space is limited. Efficiency is only one factor when evaluating a solar panel.

A solar panel for home is a photovoltaic module designed to generate electricity for residential use. Homeowners typically select system capacity based on electricity consumption, available roof area, sunlight conditions and budget. A residential system may be on-grid, off-grid or hybrid depending on the requirement.

Solar panel installation involves mounting solar modules on a suitable structure, connecting electrical wiring, installing the inverter and protection equipment, and completing the required electrical and grid connections. Proper orientation, tilt, structural strength, shading assessment, and electrical safety are important for reliable solar system performance.

Solar panel maintenance involves inspecting and maintaining solar modules and related system components to support reliable operation. It may include cleaning, checking electrical connections, inspecting mounting structures, monitoring system performance and addressing faults. Preventive maintenance requirements depend on system size, technology and environmental conditions.

A solar panel subsidy is financial support that can reduce the upfront cost of an eligible solar installation. In India, residential rooftop solar subsidies may be available through government programmes such as PM Surya Ghar, subject to eligibility and applicable guidelines.

Solar panels for homes are photovoltaic modules installed on residential rooftops or suitable structures to generate electricity. When selecting panels, homeowners should consider power rating, efficiency, dimensions, warranty, technology, roof space and compatibility with the selected inverter.

The solar payback period is the estimated time required for the cumulative financial savings from a solar system to recover the initial investment. It is generally calculated using system cost, electricity savings, solar generation, tariffs, maintenance costs and applicable incentives. Actual payback can vary as electricity prices and generation change.

A solar plant is a facility designed to generate electricity using solar photovoltaic or solar thermal technology. Solar PV plants use multiple solar modules, inverters, electrical equipment, and supporting infrastructure to generate electricity. Solar plants can range from small installations to large utility-scale projects.

Solar power is electricity generated by converting sunlight into usable electrical energy. Solar photovoltaic (PV) panels generate DC electricity, which is normally converted into AC electricity using a solar inverter. Solar power can be used for homes, businesses, industries, agricultural applications, and utility-scale projects.

A solar PPA, or solar Power Purchase Agreement, is a contract under which a buyer purchases electricity generated by a solar project under agreed commercial terms. Solar PPAs can allow businesses to access renewable electricity without necessarily purchasing and owning the entire solar asset upfront.

Solar PV means solar photovoltaic technology used to convert sunlight directly into electricity. A solar PV system typically consists of photovoltaic modules, inverters, mounting structures and electrical equipment. Solar PV systems can be connected to the grid, paired with batteries or operated independently.

Solar ROI, or Return on Investment, measures the financial return generated by a solar investment compared with the amount invested. ROI analysis can consider system cost, electricity savings, incentives, maintenance, financing costs and project life. The actual return depends on solar generation, electricity tariffs and project-specific conditions.

Solar savings refers to the reduction in electricity expenses resulting from generating electricity through a solar system. Savings depend on solar generation, electricity tariffs, self-consumption, exported electricity, system performance, financing costs and maintenance expenses. Actual savings should be estimated using site-specific electricity consumption and solar-generation data.

A solar subsidy is financial assistance provided under an eligible government programme to reduce the upfront cost of installing a solar energy system. In India, residential rooftop solar support may be available under applicable central or state programmes. Eligibility, subsidy amount, and installation requirements depend on the relevant scheme and current guidelines.

A solar subsidy calculator is a tool that estimates potential government financial assistance for an eligible solar installation. A calculator may use system capacity and applicable scheme rates to provide an indicative amount. The final subsidy is subject to official eligibility criteria, benchmark costs, verification and applicable government guidelines.

Solar subsidy in India refers to financial assistance available under central or state government programmes for eligible solar installations. Residential rooftop solar support is available under applicable government schemes, including PM Surya Ghar. Subsidy eligibility, amount and process can change, so consumers should refer to the latest official guidelines and portal information.

A solar system is a combination of components used to generate, convert, store, or distribute electricity from sunlight. A typical solar system can include solar panels, an inverter, mounting structure, cables, protection devices, meters, and batteries. Solar systems can be designed for homes, businesses, factories, and off-grid applications.

A TOPCon solar panel uses Tunnel Oxide Passivated Contact solar-cell technology. TOPCon cells are designed to reduce electrical losses and improve solar-cell performance. TOPCon modules are available in various power ratings and configurations and are increasingly used in residential, commercial and utility-scale solar installations.