Solar terms in plain words

The box after the inverter on the AC side. It holds the AC breaker and surge protection and lets the plant be switched off from the supply side before it reaches your main panel.

See also: DCDB, Inverter

The list the Ministry of New and Renewable Energy keeps of solar module makers and models that qualify for government-supported projects. It is updated and its scope has changed, so read the current version on the ministry site.

See also: DCR, MNRE

A group of modules wired together and mounted as one unit. A rooftop plant can have one array or several, for example on different roof faces.

See also: String, Module

Units your plant exports beyond what you use in a billing period, carried forward as credit under net metering. Any credit left at the end of the financial year is settled, in Chandigarh at the average power purchase cost that JERC approves.

See also: Net metering, JERC

A meter that records energy in both directions: units you draw from the grid and units you export. Net metering needs one, and your DISCOM fits or approves it.

See also: Net metering, DISCOM

A module that collects light on both faces. The extra output from the rear face depends on what is behind and under the module, and on its mounting height.

See also: Module

The subsidy the central government pays under schemes such as PM Surya Ghar and PM‑KUSUM. The amounts are set by the scheme and can change.

See also: PM Surya Ghar, PM-KUSUM

The power distribution company in the Union Territory of Chandigarh. It took over from the UT Electricity Department on 1 February 2025, per press reports, and processes net-metering applications there.

See also: DISCOM, JERC, CREST

The Chandigarh nodal agency for renewable energy. It works with resident associations and CPDL on rooftop solar and keeps the data on how many buildings have met the rooftop solar mandate.

See also: Rooftop solar mandate, CPDL, JERC

The energy a plant generates over a year divided by the energy it would generate if it ran at its full rated capacity every hour of that year, as a percentage. It lets you compare plants of different sizes.

See also: kW, kWp and kWh

Modules produce direct current. The inverter changes it to alternating current, which is what your home appliances and the grid use.

See also: Inverter

The box between the modules and the inverter. It combines the strings and holds DC protection and an isolator so the array can be disconnected for work.

See also: ACDB, String

A condition that the solar cells and modules in a plant are made in India. PM Surya Ghar pays its subsidy only for plants that use DCR modules, so ask for the model name and the manufacturer certificate.

See also: ALMM, PM Surya Ghar

The power distribution company for 12 districts of Haryana: Faridabad, Palwal, Nuh, Gurugram, Mahendergarh, Rewari, Bhiwani, Charkhi Dadri, Hisar, Fatehabad, Sirsa and Jind. It is the DISCOM that processes net-metering applications for connections in those districts.

See also: DISCOM, UHBVN, HERC

The company that supplies power to your premises, sends your bill, owns the meter and approves a rooftop plant for net metering. In Punjab it is PSPCL; in Haryana it is UHBVN or DHBVN, depending on your area; in Himachal Pradesh it is HPSEBL; in Chandigarh it is CPDL.

See also: PSPCL, UHBVN, DHBVN, HPSEBL, CPDL

Bonding the metal frames, the structure and the inverter body to earth pits so that a fault or a surge has a safe path to the ground instead of through a person.

See also: LA

A company that designs a plant, buys the equipment, builds it and hands over a working system. Wesics Energies works as an EPC for homes, farms and businesses.

All the plant output is exported through its own meter and paid at a rate set by the regulator or the DISCOM. Your own consumption is billed separately at your normal tariff. Compare net metering.

See also: Net metering

The Haryana state nodal agency for renewable energy. It runs state programmes and routes PM‑KUSUM applications in Haryana.

See also: PM-KUSUM, PEDA, HIMURJA

The Haryana electricity regulator. It sets the state rules and tariffs for electricity, including the rules that govern net metering in Haryana.

See also: PSERC, UHBVN, DHBVN

The Himachal Pradesh state nodal agency for renewable energy. The HPERC rules let either HIMURJA or HPSEBL front the rooftop scheme, so ask which one handles your application.

See also: PM-KUSUM, HPSEBL, HPERC

The Himachal Pradesh electricity regulator. It sets the state rules and tariffs for electricity, including the rooftop solar regulations that govern net metering in Himachal Pradesh.

See also: HPSEBL, HIMURJA, Net metering

The power distribution company in Himachal Pradesh. The HPERC rooftop rules name it as the distribution licensee, so it is the DISCOM that processes net-metering applications there.

See also: DISCOM, HPERC, HIMURJA

A grid-connected plant that also has a battery, so it can run selected loads during a power cut. It costs more than a plant without storage.

See also: On-grid system, Off-grid system

The device that changes the direct current from the modules into alternating current for your home and the grid. It also shuts the plant down safely when the grid is off.

See also: MPPT, String inverter, DC and AC

The regulator that covers Goa and the Union Territories, including Chandigarh. It approves CPDL's tariffs, the rooftop solar regulations and the rate paid for banked units left at the end of the year.

See also: CPDL, Banked units, Net metering

kW is power at a moment. kWp is the rated peak power of the modules under standard test conditions: a 3 kWp plant has modules that add up to 3,000 W. kWh is energy, one kW used for one hour. The "unit" on your electricity bill is one kWh.

See also: CUF

A device that catches a lightning strike and sends it to a dedicated earth, away from the modules and the inverter. It is separate from the earthing of the equipment.

See also: Earthing

The central ministry that runs PM Surya Ghar and PM‑KUSUM and keeps the approved list of module makers (ALMM).

See also: ALMM, PM Surya Ghar, PM-KUSUM

One framed sheet of solar cells. People say panel; the trade says module. A plant is many modules wired in strings.

See also: String, Array

Electronics in the inverter that keep the modules at the voltage where they give the most power as sun and temperature change through the day. Each MPPT input takes one or more strings.

See also: Inverter, String

Your plant first feeds your own load. What you do not use goes to the grid. One bi-directional meter counts units drawn and units exported, and your bill is based on the net. Your DISCOM approves it under the rules of the state regulator.

See also: Gross metering, Bi-directional meter, DISCOM

The cleaning, inspection, repair and reporting that keeps a plant producing. PM Surya Ghar expects the installer to maintain a home plant for five years.

See also: Soiling

A plant with batteries that is not connected to the grid. It suits places with no supply but needs battery replacement over its life and does not qualify for net metering.

See also: On-grid system, Hybrid system

A plant connected to the DISCOM supply. It runs only while the grid is up, and exports surplus under net metering. Most home and business rooftop plants are on-grid.

See also: Net metering, Hybrid system

The years it takes for your savings to repay what you paid, after subsidy. It depends on your tariff and usage, so treat any single figure as an estimate.

See also: Tariff

The Punjab state nodal agency for renewable energy. It runs state programmes and routes PM‑KUSUM applications in Punjab.

See also: PM-KUSUM, HAREDA, HIMURJA

The central scheme that pays financial assistance for rooftop solar on homes. It needs DCR modules and an application on the national portal. Himachal Pradesh gets higher amounts as a special-category state.

See also: CFA, DCR, Special-category state

A central scheme for farmers with three components: grid-connected solar plants on farmland, stand-alone solar pumps, and solarising existing grid-connected pumps. Applications go through the state agency: PEDA in Punjab, HAREDA in Haryana, HIMURJA in Himachal Pradesh. The central grant is higher in Himachal Pradesh (50 percent of the benchmark cost, against 30 percent elsewhere). PEDA states that PM‑KUSUM 1.0 closed on 31 December 2025.

See also: PEDA, HAREDA, HIMURJA, CFA

The Punjab electricity regulator. It sets the state rules and tariffs for electricity, including the rules that govern net metering in Punjab.

See also: HERC, PSPCL

The power distribution company for Punjab. It is the DISCOM that processes net-metering applications for connections in the state.

See also: DISCOM, PSERC

Technology that turns sunlight directly into electricity in a semiconductor, usually silicon. Solar PV is the kind of solar on rooftops and farm plants.

See also: Module

A building rule that requires a solar plant instead of leaving it to the owner. In Chandigarh it applies to houses on plots of 500 sq yd and above and to government, institutional and commercial buildings. Check the current bylaws for any smaller threshold.

See also: CREST

The maximum load your DISCOM has approved for your connection. It is printed on your bill, and the size of a rooftop plant is checked against it when net metering is approved.

See also: DISCOM, Net metering

A shadow on the modules from a tank, parapet, tree or another row. Shade on one module can pull down the whole string it is wired in, which is why we map shade before we design.

See also: String

Dust, bird droppings and film that settle on the glass and cut the output. Washing with a soft brush and low-TDS water removes it.

See also: O&M

A state or Union Territory that the central schemes treat as a hill or remote area and pay at higher rates. Himachal Pradesh is one, so PM Surya Ghar pays more there. Punjab, Haryana and Chandigarh are not.

See also: PM Surya Ghar, CFA

Modules wired in series, one after another, so their voltages add up. One or more strings connect to each MPPT input of the inverter.

See also: MPPT, Array

One inverter that takes several strings of modules. It is the common choice for home and small business plants.

See also: Inverter, String

The price per unit (kWh) your DISCOM charges, which depends on your category and on how much you use. The state regulator approves it. Solar savings are the units you no longer buy times your tariff.

See also: Net metering, Payback period

Tilt is the angle of the modules from flat. Azimuth is the compass direction they face. In India, modules normally face south.

See also: Shading

The power distribution company for 10 districts of Haryana: Panchkula, Ambala, Yamunanagar, Kurukshetra, Kaithal, Karnal, Panipat, Sonipat, Rohtak and Jhajjar. It is the DISCOM that processes net-metering applications for connections in those districts.

See also: DISCOM, DHBVN, HERC