How to understand your electricity bill

The supply charge, sometimes called the daily supply charge, service to property charge or fixed charge, is what you pay for having a connection. It is expressed in cents per day and multiplied by the number of days in the billing period. It does not fall if you use less electricity and it does not stop when you go away.

The usage charge is expressed in cents per kilowatt hour and multiplied by your consumption. A kilowatt hour is one kilowatt drawn for one hour — a two-kilowatt heater running for thirty minutes uses one kilowatt hour. The bill will normally show your average daily usage and often a comparison against similar households in your area, which is useful as a sense check and nothing more.

The National Metering Identifier, or NMI, identifies your connection point. Keep it — it is what you quote when switching retailers, reporting a fault, or checking whether an offer applies to your address. In Western Australia and the Northern Territory the equivalent identifier and the market structure differ, because those jurisdictions sit outside the national retail framework.

The bill also names your distributor, which is the business that owns the poles, wires and meter serving your property. You cannot choose your distributor and you do not pay it directly; its network charges are embedded in what your retailer bills you. Roughly half of a typical residential bill is network cost, which is why two retailers in the same suburb are never as far apart as their marketing suggests.

Concessions and rebates appear as separate lines, usually as a deduction rather than a discount off the rate. Pay-on-time discounts, direct debit discounts and conditional discounts appear either as a deduction or as a warning about what you will lose if you pay late.

The billing period matters more than people expect. A quarterly bill covering a hot summer is not comparable to one covering a mild autumn, and comparing a 92-day bill with an 88-day bill without adjusting for the day count produces a false conclusion about whether anything changed.

Finally, the bill shows your plan name and, in most cases, your benefit period end date — the point at which an introductory discount expires and the rate reverts. That date is the single most useful thing on the page and the one nobody diarises.

A single rate or flat tariff charges the same cents per kilowatt hour whenever you use electricity. It is the simplest structure and the easiest to compare, and it suits households whose usage is spread through the day or who cannot control when they use power.

A time-of-use tariff splits the day into peak, shoulder and off-peak periods, each with a different rate. Peak periods are typically weekday late afternoon and evening. This tariff rewards a household that can shift dishwashing, laundry, pool pumps and electric vehicle charging into off-peak windows, and penalises one that cannot.

A demand tariff adds a separate charge based on the highest rate of consumption reached during a defined window in the billing period — the single half-hour or hour when you drew the most power. The logic is that networks are built for peaks rather than for totals. In practice it means one evening of running the oven, the air conditioner, the dryer and the pool pump simultaneously can set a charge that applies for the whole period.

A controlled load tariff, sometimes shown as off-peak 1 or off-peak 2, prices a specific circuit — usually an electric hot water system or slab heating — separately and cheaply, because the distributor controls when it runs. If you have this, it appears as its own usage line with its own rate.

A block or stepped tariff charges one rate for the first quantity of electricity used in the period and a different rate beyond it. It has become less common in residential offers but still appears in some regions.

Solar households have a feed-in tariff as well, which is the credit paid for electricity exported to the grid. It is a separate rate from what you pay to import, and in most of the country it is now considerably lower than the import rate, which is why self-consumption matters more than export volume.

Which tariff you are on is written on the bill, though not always in plain language. Where a smart meter has been installed, moving to time-of-use or demand pricing is common, and the change is usually notified rather than negotiated. You can generally ask your retailer what tariffs are available at your address and whether you may move — the answer depends on your distributor's tariff structure as well as the retailer's offers.

Electricity offers are almost impossible to compare on rates alone, because a plan with a low usage rate and a high supply charge can cost more than the reverse depending on how much you use. The reference price exists to solve exactly this.

In New South Wales, South Australia and south-east Queensland, the Australian Energy Regulator sets a Default Market Offer each year. It is both a price cap for standing offer customers and a benchmark: every market offer must be expressed as a percentage above or below the reference price for a representative household in your distribution zone.

Victoria runs its own equivalent, the Victorian Default Offer, set by the Essential Services Commission, with the same dual role as a safety-net price and a comparison point.

That percentage is the number to compare. It bundles the supply charge and the usage charges into one figure calculated on a standard consumption profile, so two offers quoted against the same reference price are genuinely comparable in a way that two lists of rates are not.

Its limitation is that it assumes an average household in your zone. If your consumption is much higher or much lower than the assumed profile, or heavily concentrated at particular times, the ranking can differ from your actual outcome. Use the percentage to shortlist, then check the specific rates against your own usage from a recent bill.

Conditional discounts complicate the picture deliberately. An offer advertised as a large percentage below the reference price may assume you always pay on time. Check whether the discount is conditional and what happens if it is lost.

The government comparison sites are the reliable way to do this: Energy Made Easy, run by the AER, covers most of the country, and Victorian Energy Compare covers Victoria. Both are free, take your usage data rather than an estimate if you upload a bill, and neither takes a commission, unlike commercial comparison sites which are paid by the retailers they list.

Check whether the read on your bill is actual or estimated. It will be marked, usually with a letter code beside the reading. An estimate is a projection from historical usage, not a measurement.

If the bill is estimated and looks wrong, ask for a special meter read or submit your own reading. Retailers generally accept a customer read supported by a photograph of the meter display, and will adjust the bill.

Estimated bills self-correct at the next actual read, which is why an unusually low estimate is followed by an unusually high catch-up bill. If a series of estimates has built up, ask for the account to be reconciled rather than paying a large catch-up in one instalment.

Smart meters, or advanced meters, record consumption in short intervals and report it remotely, which removes estimates and lets you see your usage by time of day through your retailer's portal. They are being rolled out progressively across the national market, and the AER publishes what retailers must tell you and what your rights are during the rollout.

The consequence people are not warned about is tariff structure. Interval data makes time-of-use and demand tariffs possible, and installation is frequently accompanied by a change of tariff. Ask before installation what tariff you will be on afterwards, and ask again on the next bill.

Use the interval data once you have it. Seeing that a specific hour each evening accounts for a large share of your bill is far more actionable than a quarterly total, and it is the only way to tell whether a demand tariff is actually costing you anything.

If your meter is faulty, the fix belongs to your distributor, arranged through your retailer. Testing a meter can be requested, and where the meter is found to be inaccurate the bill is adjusted.

If you have rooftop solar, your bill shows imported electricity charged at your usage rate and exported electricity credited at your feed-in tariff. Because feed-in rates have fallen well below import rates in most of the country, a system that exports heavily and self-consumes little produces a much smaller saving than the panel count suggests. Running appliances during daylight hours is usually worth more than the export credit.

Solar customers on time-of-use tariffs face a particular quirk: solar generation peaks in the middle of the day, while the expensive peak period is in the evening after generation has stopped. Batteries and load shifting address this; more panels do not.

Every state and territory offers energy concessions to people holding eligible concession cards, and most offer additional rebates for families, medical energy needs where equipment must run continuously, and life support registration. These are not applied automatically. You must give your card details to your retailer, and the concession appears as a line on the bill from the next billing period, not retrospectively for years you did not claim.

If you rely on life support equipment, register with your retailer and distributor. Registration triggers protections including notice of planned interruptions and restrictions on disconnection.

Where the bill is genuinely unaffordable, retailers operating under the national framework must have a customer hardship policy approved by the AER, and it must be offered rather than merely available on request. It covers payment plans, protection from disconnection while you are meeting a plan, and referrals to financial counselling.

Asking for hardship assistance does not affect your credit rating and does not stop you switching retailers. Not asking, and then defaulting, does both.

Free financial counselling is available nationally through the National Debt Helpline, and energy retailers are required to tell you about it. Financial counsellors negotiate with retailers routinely and often obtain outcomes an individual customer would not.

Your retailer owns everything about the money: rates, tariffs, plan changes, discounts, concessions, payment plans, hardship and the accuracy of the account. Almost every billing complaint starts here.

Your distributor owns the physical supply: outages, voltage problems, damaged lines, the meter itself, new connections and upgrades. You do not choose them and you cannot switch away from them. If the power is out, calling your retailer wastes time — the fault number is on the bill and on the distributor's website.

Start any dispute with the retailer in writing, describing the specific charge you dispute and what outcome you want. Ask for a bill review, which is a defined process, and ask for the meter data supporting the charge. Retailers are required to have a complaints process and to tell you about the ombudsman.

If the retailer's answer is unsatisfactory, take it to the energy ombudsman in your state. Every state and territory has one, they are free to consumers, and they can require a retailer to correct a bill, waive charges or reinstate a discount. In New South Wales it is the Energy and Water Ombudsman NSW; equivalent schemes operate in the other jurisdictions and the AER publishes the contact list.

The AER itself regulates retailers and distributors but does not resolve individual complaints — it enforces the rules and takes action on systemic breaches. Reporting a problem to the AER is worth doing where you think a retailer's conduct is a pattern, but the ombudsman is what gets your bill fixed.

Where a retailer has back-billed you for a long period because of an undercharge, there are limits on how far back a retailer may recover, and the amount must be offered on an interest-free instalment plan over a comparable period. This is one of the most commonly overlooked consumer protections in the retail rules.

Keep your bills. A dispute about a tariff change or a lost discount is decided on what the bills and the plan documents actually said, and retailers do not always retain a customer-accessible history for as long as the dispute takes.