The Basics of Solar Energy

If you are considering solar for the first time, the terminology gets in the way quickly. Kilowatts and kilowatt-hours, inverters and feed-in tariffs, self-consumption and export limits — none of it is complicated, but most explanations assume you already know half of it.

Here is how rooftop solar actually works, in plain terms, with Brisbane specifics where they matter.

How a solar system works, start to finish

There are four stages, and that is genuinely all of it.

1. Panels generate DC electricity. Sunlight hits silicon cells and produces direct current. More light means more output — which is why panel orientation and shading matter so much.

2. The inverter converts DC to AC. Your home runs on alternating current, so the inverter converts it. This is the component doing the most work, and the one most likely to need replacing first.

3. Your home uses what it needs. Generated power flows to whatever is running — the fridge, air conditioning, the pool pump. This happens automatically and always takes priority.

4. Surplus is exported or stored. Anything you do not use flows back to the grid, earning a feed-in tariff. If you have a battery, it charges first and exports afterwards.

kW versus kWh: the distinction that matters

These get used interchangeably and they mean quite different things.

Kilowatts (kW) measure capacity — how much your system can produce at any instant. A 6.6kW system produces up to 6.6 kilowatts under ideal conditions.

Kilowatt-hours (kWh) measure energy over time — what your electricity bill charges you for. That same 6.6kW system might generate around 26 kWh across a good Brisbane day.

A useful analogy: kW is how fast a tap runs, kWh is how much water ends up in the bucket.

Battery capacity is quoted in kWh, because what matters is how much energy it holds, not how quickly it delivers it.

What Brisbane roofs actually produce

Brisbane sits in Solar Zone 3, which receives more usable sunlight than most of Australia. As a rough guide, expect around 4 kWh per day for every 1kW installed, averaged across the year.

So a 6.6kW system produces roughly 26 kWh daily on average — more in summer, less in winter, less again on overcast days.

Orientation changes this:

North-facing gives the highest total output
West-facing produces less overall but generates later, which suits homes using air conditioning in the afternoon
East-facing favours morning generation
Split east-west flattens the curve, often better for self-consumption than a single north array

Shading matters more than people expect. With string inverters, one shaded panel can drag down an entire string — which is why microinverters or optimisers are sometimes worth the extra cost on complex roofs.

Self-consumption: where the savings actually come from

This is the concept that determines whether solar pays off well or merely adequately.

In Queensland you buy electricity at one rate and sell surplus back at a much lower feed-in tariff. So every kilowatt-hour you generate and use yourself is worth considerably more than one you export.

Practical consequences:

Running the dishwasher, washing machine and pool pump during daylight increases your return
A household home during the day gets more from solar than one empty until 6pm
Oversizing a system that mostly exports is a poor investment
A battery raises self-consumption by storing daytime surplus for evening use

This is why a good installer asks about your daily routine rather than only your roof.

What the components do

Panels — typically 400 to 450 watts each. Fourteen 470W panels make roughly a 6.6kW system. Panel efficiency varies less between quality brands than marketing suggests.

Inverter — either a single string inverter for the whole array, or microinverters on individual panels. String inverters cost less; microinverters handle shading and mixed orientations better and report per-panel.

Mounting — rails fixed to rafters with flashing. Unglamorous, and where poor installations show up first.

Monitoring — an app showing generation, consumption and export. Worth having; it is how you notice a fault rather than discovering it on a bill months later.

Battery — optional. Stores surplus for evening use or blackout backup. See battery storage for when it makes sense.

Feed-in tariffs in Queensland

South East Queensland has no regulated feed-in tariff — retailers set their own, and rates vary meaningfully between them.

Two things follow. First, it is worth comparing retailers after installing solar, not before. Second, feed-in tariffs are low enough that self-consumption should drive your system design.

What it costs and what comes back

System cost depends on size, components and installation complexity. The federal rebate is applied as a discount on your invoice rather than claimed later — we explain the mechanism, and the January 2027 change, in our rebate guide.

Rather than quote generic payback figures, our case studies show real Brisbane installations with actual system sizes and measured savings.

Common first questions

Do I need to be home during installation?

Usually for access and a brief handover. Most residential installs take a day.

Will I still get an electricity bill?

Yes. You remain grid-connected and pay a daily supply charge, plus any power drawn outside generating hours. The bill should be considerably smaller.

What happens in a blackout?

Grid-connected solar shuts down automatically for electrical safety. Backup power during an outage requires a battery configured for it.

How long does approval take?

Your installer handles the retailer application. Timelines vary, but connection approval typically takes a few weeks.

Working out what suits your home

The specifics that matter are your bills, your roof orientation, any shading, and when you actually use power. Everything else follows from those.

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