How rooftop solar systems work

How do rooftop solar systems work? Photovoltaic (PV) modules on the roof convert sunlight into direct current electricity. An inverter converts that DC into alternating current that household circuits, and the grid, can use. Electricity you use while the system is generating offsets what you would otherwise import. Unused generation may be exported through your meter, subject to network and retailer rules, or stored if a battery is part of the design. That is the whole machine. The rest of this hub is the Australian detail around it.

This page is the how-it-works room of the guide. It is not a shopping list. For architectures, continue to system types. For storage, see batteries. For certificates and state programs, see rebate basics. Confirm product and installer rules with the Clean Energy Regulator, energy.gov.au, the Clean Energy Council, and Solar Accreditation Australia.

The energy path, without sales language

Sunlight arriving at a panel is not the same as the temperature on the driveway. Panels respond to irradiance — how much light energy hits the glass — and they have their own temperature behaviour. A hot, bright roof can produce less than a cooler bright roof. Dust, leaf litter, and even light shading from a vent pipe change the curve. String layout and module-level electronics are how designers try to isolate those losses. You do not need to pick a topology on this page; you need to know that shading is a design input, not a surprise after install day.

DC from the array travels in appropriately rated cable to the inverter, usually mounted near the switchboard or on a garage wall. The inverter’s job is conversion, grid synchronisation, safety disconnect, and, in many modern units, monitoring. Australian grid-connect inverters operate under standards and connection requirements that your distribution network service provider (DNSP) enforces. When the grid is down, a plain grid-tied inverter is designed to stop exporting so it cannot energise a line a worker thinks is dead. Backup during a blackout is a separate design, covered on the system-types and batteries hubs.

AC from the inverter lands at the switchboard. Household loads take what they need. The meter records imports and, if you are set up to export, exports. Your retailer bills the imports under your tariff and credits exports under a feed-in arrangement if you have one. Those rates are not published on this site because they are not ours to invent and they change.

Capacity, energy, and the bill

Kilowatts describe size. An array rating in kW is a capacity under test conditions, not a promise of daily output. Kilowatt-hours describe energy over time — what the house used last quarter, what the array generated last Tuesday. Installers should talk in both. If a conversation only uses one number, ask for the other.

Self-consumption is the energy you use on-site while generating. Export is the remainder, if the network allows it. A household that runs a dishwasher at noon will usually self-consume more than a household whose load peaks at 7 pm. That observation is not a payback model. It is why “solar” and “the evening peak” are different problems, and why batteries appear in a later hub.

The Clean Energy Regulator’s rooftop solar guidance is explicit that how you use generation — self-consume, export, or store — is a household decision inside a regulated scheme. energy.gov.au walks consumers through choosing retailers and installers and through installation day. Read those pages as the official companion to this explainer.

Panels, inverters, and what “approved” means

For small-scale technology certificates, eligible systems generally need listed products and an accredited designer/installer pathway. The Regulator’s rooftop solar pages describe product and capacity tests; the Clean Energy Council publishes approved-product resources that industry still uses as a consumer check. Lists move. A model that was listed last year may not be the model on today’s quote. Write the exact model numbers down and search them on the current lists the day you compare proposals.

Inverters come in string, hybrid, and microinverter families. A string inverter converts a group of panels. Microinverters convert at the module. Hybrid inverters are built to manage a battery as well as the array. None of those families is “best” in the abstract. Roof geometry, shading, existing equipment, and whether storage is in scope decide the conversation. This hub will not rank them.

Mounting, wind region, roof material, and waterproofing are building issues as much as electrical ones. A competent installation includes flashings, cable management, isolation, and labelling a firefighter can read. Those are standards questions. Ask what standard the design is to, and who signs the electrical certificate in your state.

Orientation, pitch, and the Australian roof

A textbook north-facing array suits many southern Australian houses, but east-west splits are common on ridgelines and on households that want morning and afternoon generation rather than a midday spike. Pitch follows the roof unless a tilt frame is specified. Trees grow. Neighbours build. A shade study at design time is worth more than a stock photo of a perfect north plane.

Location still matters in the certificate world: the Regulator uses postcode zones when calculating small-scale technology certificate entitlements for PV. That is an official mechanism, not a sales climate score. We do not reproduce zone tables here because they belong on cer.gov.au. If a quote mentions a zone, ask the designer to show the official table they used.

Monitoring: what the app actually tells you

Most contemporary inverters offer an app or web portal. At their best, they show generation, household consumption if a consumption meter was installed, export, and fault codes. At their worst, they show a sun icon and a marketing dashboard. Before you treat an app as evidence, ask whether consumption monitoring is included, how data is stored, and what happens if the Wi-Fi drops. Monitoring is a diagnostic tool. It is not a warranty.

If generation falls off a cliff, the first checks are still physical: breaker positions, isolation switches, a grid outage, a firmware notice, or a string of panels under a new shadow. Licensed electricians diagnose; this guide does not.

Connecting to the grid

A rooftop system that exports or even that sits parallel with the grid needs the network’s permission. DNSPs set size thresholds, export limits, and inverter settings. Some suburbs are constrained; some are not. Approval is a process with forms and time, not a sticker. Your retailer also needs the right meter configuration. AEMO’s public material is the national context: distributed PV is visible in operational data, which is why networks care about how inverters behave.

Ask, in writing, who lodges the connection application, what export limit is being sought, and how the meter will record feed-in. If the answer is vague, the quote is incomplete.

Safety, accreditation, and who must be on site

energy.gov.au states that systems must be installed by an accredited installer to access Australian Government rebates under the Small-scale Renewable Energy Scheme, and that Solar Accreditation Australia is the scheme operator after the transition from the Clean Energy Council. Accreditation is for the person. On installation day, energy.gov.au notes that an accredited installer should be physically present for set-up, a mid-installation check, and testing and commissioning. Ask for the accreditation number and check it on SAA’s status page before and on the day.

Electrical licensing is a state matter. Isolation, residual-current devices, shutdown labelling, and battery placement (if any) are not optional extras. If a worker cannot explain the shutdown procedure, stop the job and call the retailer.

What this hub is for

This page exists so you can walk into a design conversation knowing the path: light, DC, inverter, AC, household, export or storage. It exists so kW and kWh do not get swapped. It exists so “the app” is not mistaken for a connection approval. It does not exist to tell you a system size, a brand, or a payback. Those answers require a roof, a bill history, a network area, and a licensed person.

When the path is clear, read system types to see how grid-tied, hybrid, and off-grid architectures change the last step of the diagram. Then keep every incentive claim for the rebates hub and for official sites on the day you sign.

After commissioning

A finished grid-connect system should come with documentation you can actually file: a single-line diagram, product serials, warranty contacts, the electrical certificate required in your state, and the shutdown procedure. Keep them off the kitchen fridge magnet and in a folder you can find during an insurance or service call. Monitoring logins should be in your name where the platform allows it, not only in the retailer’s.

Generation will not be a flat line. Seasons, soiling, a new tree, and a firmware update all move the curve. Use the first clear week as a baseline in the app, not as a guarantee of next July. If output collapses, start with the physical checks named earlier and then call the installer — this hub stops at literacy, not fault-finding.