Solar glossary for Australia — plain-English definitions

A

AC coupling

Wiring a battery on the AC side of the system, through its own inverter, rather than sharing the solar inverter. Simpler to retrofit onto an existing system; slightly less efficient than DC coupling because the power is converted twice.

Accreditation

Installer approval issued through the industry scheme. A certificate claim needs an accredited person’s details against the install, which is why the accreditation number sits on the job rather than on the company.

Azimuth

The compass direction a roof plane faces, in degrees. In Australia due north is the productive direction, and a plane’s azimuth together with its tilt decides how much of the year’s sun it actually collects.

B

Battery factor

The multiplier used to turn certifiable battery capacity into certificates. It steps down: 9.3 for a 2025 install, 8.4 for January–April 2026, and 6.8 from 1 May 2026.

Bifacial

A panel that also generates from light striking its back. Worth something on a light-coloured or elevated surface, close to nothing flat on a dark tiled roof — the gain depends on what is underneath it.

C

CEC

The industry body whose approved-product lists decide which panels, inverters and batteries can be used in a certificate claim. A product missing from the list is not a claimable product, whatever its datasheet says.

CER

The Commonwealth regulator that runs the certificate scheme, sets the zone ratings and deeming periods, and audits claims.

Certifiable capacity

The part of a battery’s capacity that earns certificates. From 1 May 2026 it is tiered: the first 14 kWh counts in full, 14–28 kWh at 60%, and 28–50 kWh at 15%. A 20 kWh battery is therefore certifiable at 17.6 kWh, not 20.

Certificate of Compliance

The electrical certificate issued after the install, naming the licensed person responsible for the work. Required before a claim is complete and before most distributors will connect the system.

Clipping

What happens when an array can produce more DC power than the inverter can convert, so the peak is cut off. A little clipping is deliberate and economic; a lot means the inverter is undersized for the array.

Curtailment

Output deliberately held back — by an export limit, by the inverter, or by the network at times of high voltage. Generation the customer paid for and does not receive.

D

DC coupling

Wiring a battery on the DC side, sharing the solar inverter. More efficient than AC coupling because there is one conversion instead of two, but it usually means choosing the battery and inverter together.

DC:AC ratio

Array DC capacity divided by inverter AC capacity. Australian systems are commonly oversized above 1.0 because a panel rarely produces its nameplate output; the scheme caps the ratio for a claim at 1.33.

DNSP

The distributor that owns the poles and wires in an area, and the body that approves a connection and sets the export limit. Not the retailer — a customer can change retailer and keep the same DNSP.

Deeming period

The number of years of future generation a system is credited with up front. It is the years from installation to the end of the scheme — five for a 2026 install, four for 2027 — and it steps down every 1 January.

E

Export limit

The maximum the distributor will let a system push back into the grid, in kW or kVA. It constrains the system before the roof does, which is why it belongs in the design rather than in the paperwork afterwards.

F

Feed-in tariff

What a retailer pays for exported energy, per kWh. Set by the retailer within state rules and generally far below the retail rate, which is why self-consumption is worth more than export.

H

Hybrid inverter

An inverter that handles both solar and a battery. Fewer boxes on the wall and one warranty, at the cost of tying the two choices together.

I

Interval data

Consumption recorded in 30-minute or 15-minute blocks by a smart meter, usually supplied as a NEM12 file. The only honest basis for a savings estimate — without it a payback figure is an assumption about when someone is home.

Isolator

A switch that physically disconnects part of the system so it can be worked on safely. Their number and placement is what most site-plan diagrams exist to record.

K

kWp

Kilowatts peak — an array’s rated DC output under standard test conditions. A real roof rarely sees those conditions, so kWp is a label for comparison rather than a promise of output.

L

Load profile

The shape of a household’s usage across a day and a year. Two homes using the same total energy can have completely different profiles, and therefore different self-consumption and different paybacks.

M

MPPT

Maximum power point tracker — the part of the inverter that continuously finds the voltage at which a string produces the most power. An inverter with several trackers can run roof planes of different orientation independently.

Microinverter

A small inverter mounted at each panel rather than one for the whole array. Shade on one panel then costs only that panel, at a higher cost per watt and more hardware on the roof.

N

NEM12

The standard Australian file format for interval meter data. Retailers and distributors supply it on request, and it is what turns a savings estimate from a guess into a calculation.

NMI

National Meter Identifier — the number that identifies a connection point on the network. It appears on the customer’s bill and is what a distributor application is keyed to.

Nameplate

A device’s rated capacity as printed by its maker. Useful for comparison and for compliance limits; not a prediction of what a specific roof will produce.

O

Orientation

Which way a roof plane faces. In Australia north is best, east and west are workable and shift generation towards morning or evening, and south is usually left empty.

P

Payback period

How long the savings take to cover the cost. Only meaningful when the savings are computed from a real load profile — otherwise it measures the assumption, not the system.

Pitch

The angle of a roof plane from horizontal, in degrees. It changes how much sun a plane collects and how much ground area a panel covers, which is why a layout drawn without it overstates coverage.

Pre-approval

The distributor’s permission to connect a system of a given size, obtained before the install. Skipping it is how a finished system waits weeks to be switched on.

S

STC

Small-scale Technology Certificate — the tradeable unit the federal scheme creates for a small system. Certificates are generated up front for expected output, then sold, which is why they show on a quote as a discount.

Self-consumption

The share of generation used on site rather than exported. It is where most of the savings are, because avoiding a retail rate is worth several times what a feed-in tariff pays.

Shading

Anything that puts a shadow on a panel — a tree, a chimney, the next roof. What matters is when and for how long, not whether: a shadow at 8am in June costs far less than one at noon.

Single line diagram

A one-page schematic of the electrical system — array, strings, inverter, isolators, switchboard. Required for most connection applications and for the installer on the day.

Spot price

The traded price of a certificate on a given day. Traders quote gross or net of their fees, which is why three quotes for the same batch can look like three different prices.

String

A group of panels wired in series into one inverter input. The count is limited at the top by the cold-morning voltage the inverter can survive and at the bottom by the voltage it needs to start.

T

Three-phase

A supply with three active conductors rather than one. It allows a larger inverter and a higher export limit, and whether a site has it changes the system you can quote.

Tilt

The angle a panel sits at, whether following the roof or lifted on a frame. Together with orientation it decides annual yield, and it also foreshortens the area a panel covers when seen from above.

U

Usable capacity

The part of a battery that can actually be cycled, as opposed to its nominal size. On modern lithium-iron-phosphate batteries sold in Australia these are usually the same number — the old 90% rule of thumb comes from a different chemistry.

V

VPP

Virtual power plant — an arrangement where a retailer or aggregator can call on a fleet of home batteries. It pays the customer for access and changes how the battery is dispatched, which changes the savings model.

Voc

Open-circuit voltage — the voltage a panel or string produces with nothing drawing from it. It rises as temperature falls, so string sizing is checked against the coldest morning a site sees, not against a typical day.

Z

Zone rating

The CER’s figure for how productive a location is, used directly in the certificate calculation. Australia has four zones: Zone 2 is 1.536, Zone 3 is 1.382 (Sydney, Adelaide, Perth) and Zone 4 is 1.185 (Melbourne, Hobart).

The words the job actually uses.

A