FAQ
More Common Questions About Bills, Solar, Batteries, EVs and Commercial Demand Charges.
This FAQ page helps customers quickly understand electricity bill issues, solar and battery choices, EV charging, rebates, VPP, backup power and commercial peak demand.
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Expanded questions are organised by the way customers normally think about their energy bill.
Electricity Bill Review
Understand what is inside the bill and why the cost changes.
Why did my electricity bill increase even though my usage looks similar?
Your bill can increase because of higher rates, changes to time-of-use pricing, lower solar feed-in credits, more peak-period usage, higher supply charges or demand charges.
What is the difference between usage charge and supply charge?
Usage charge is based on how much electricity you use, usually measured in kWh. Supply charge is a fixed daily charge for being connected to the network.
What should I check first on my bill?
Check total usage, billing days, peak/off-peak split, daily supply charge, solar feed-in credit, tariff type and any demand charge line item.
Why is my bill still high after installing solar?
Common reasons include high evening usage, low feed-in rate, wrong tariff, low self-consumption, shading, small system size or EV charging outside solar hours.
Why is my solar feed-in credit so low?
Feed-in rates are often much lower than grid purchase rates. The biggest saving usually comes from using your own solar instead of exporting it.
Can a bill review tell me if my tariff is wrong?
It can identify signs that the tariff may not suit your usage pattern, such as high peak usage, low off-peak usage or demand charges. A retailer comparison may then be needed.
Why should I upload the full bill instead of only the amount?
The full bill shows tariff names, rates, daily charges, solar credits, demand charges and billing period. These details are needed for a more useful review.
Residential Solar + Battery
Questions about solar savings, battery size, self-consumption and backup.
How does solar reduce my electricity bill?
Solar reduces the amount of power you buy from the grid during daylight hours. Savings are strongest when you use solar onsite.
How does a battery reduce my bill?
A battery stores excess solar during the day and discharges later, often during evening or peak tariff periods when grid power is more expensive.
Is a bigger battery always better?
No. Battery size should match your solar generation, evening usage, tariff and backup needs. Oversizing can reduce value.
Can I add a battery to my existing solar system?
Often yes, but it depends on inverter compatibility, switchboard condition, available space, battery brand and whether AC-coupled or hybrid battery design is better.
Can a battery work without solar?
It may work by charging from the grid during cheaper periods and discharging during expensive periods, but the value depends heavily on your tariff and usage pattern.
Can solar and battery reduce my peak usage?
For homes, it can reduce grid import during peak-price periods. For businesses, battery control may also help reduce peak demand if configured correctly.
Will a battery automatically back up my whole home?
Not always. Backup requires the correct inverter/gateway and essential-circuit design. Some systems back up only selected loads.
What information is needed to size solar and battery properly?
Recent bills, smart meter interval data, roof space, phase supply, daytime usage, evening usage, EV charging needs and backup requirements all help.
Commercial Demand Charge
Demand charges can be a hidden cost for businesses with short high-load events.
What is a demand charge?
Demand charge is based on the highest power draw during a billing period, often measured in kW or kVA. A short high-load event can increase the bill.
Why do commercial customers have demand charges?
Businesses can create short peaks that require network capacity. Demand charges help recover the cost of supporting that capacity.
How do I know if my business has a demand charge problem?
Look for demand charge line items, high kW/kVA readings, or situations where demand charges make up a meaningful share of the total bill.
How can a business reduce demand charge?
Common methods include staggering equipment starts, monitoring demand, controlling EV charging, shifting loads and using batteries for peak shaving.
What is peak shaving?
Peak shaving means reducing grid import during short demand spikes. A battery can discharge when site load approaches a set limit.
Can solar reduce demand charges?
Solar can help if peak demand occurs during solar generation hours. If the peak happens early morning, evening or during cloudy periods, a battery or load control may be needed.
How do I set up battery peak shaving?
The battery/inverter must support demand control, and the system needs a target demand limit, metering, control settings and commissioning based on the site load profile.
What businesses often have demand charge issues?
Cafés, restaurants, workshops, cold storage, offices with HVAC, childcare centres, warehouses and sites with EV charging can have demand peaks.
EV Charging
How EV charging affects home and business electricity costs.
Can EV charging increase my electricity bill?
Yes. EV charging can become one of the largest loads. Charging time, charger power, tariff and solar availability all matter.
Can I charge my EV using only solar?
Some smart chargers can follow solar surplus, but it depends on solar size, home load, charger compatibility and vehicle charging requirements.
What size home EV charger do I need?
Many homes use 7kW single-phase charging, while three-phase homes may support higher power. The best option depends on supply capacity and driving needs.
Can EV charging overload my home?
It can if the charger is too large for the supply or if many appliances run at the same time. Load management may be needed.
Should I charge my EV off-peak?
Off-peak charging can reduce cost if your tariff has cheaper overnight rates. Solar charging may be better when solar surplus is available.
What is V2H?
V2H means vehicle-to-home, where a compatible EV can power the home. It requires compatible vehicle, charger and approval.
What is V2G?
V2G means vehicle-to-grid, where a compatible EV can export energy to the grid. It depends on vehicle, charger, retailer/network rules and program availability.
Rebates & Programs
STCs, battery programs and eligibility questions.
How does the STC solar rebate work?
STCs reduce the effective upfront cost of eligible solar systems. The value depends on system size, location, certificate value and installation requirements.
Does every solar system qualify for STCs?
Eligibility depends on approved products, accredited installation and compliance requirements. The installer should confirm eligibility before quoting.
How do battery programs help customers?
Battery programs may reduce upfront cost or offer credits, but customers should check eligibility, control rules, backup impact and long-term value.
Can rebates change over time?
Yes. Rebate rules, values and eligibility can change. Customers should confirm current program details before deciding.
Can PowerIdeas.au check my rebate options?
Yes. We can review your bill, system needs and property details, then identify relevant solar, battery or energy program options.
Should I choose the cheapest system after rebate?
Not always. Product quality, warranty, installation standard, monitoring, support and battery compatibility are important.
VPP & Backup Power
Virtual Power Plant participation and backup power design.
What is a VPP?
A Virtual Power Plant connects many batteries and can use them to support the grid. Customers may receive credits or incentives depending on the program.
Will VPP affect my battery backup?
It may, depending on the program settings and battery reserve. Customers who need backup should check reserve settings and control rules.
Can I leave a VPP program later?
It depends on the program contract and provider rules. Customers should check exit terms before joining.
Does a battery provide backup during every blackout?
Only if the system is designed for backup and the battery has enough charge. Some systems do not include backup circuits.
What loads should be on backup circuits?
Common backup loads include fridge, lights, internet, selected power points and essential equipment. Large loads may drain the battery quickly.
Can a battery back up a three-phase home?
It depends on the battery/inverter design. Some systems support selected phases or selected circuits rather than the whole site.
Tariffs & Retailer Plans
Peak, off-peak, controlled load and plan structure questions.
What is peak, shoulder and off-peak electricity?
These are different price periods. Peak is usually most expensive, off-peak is cheaper, and shoulder sits between them.
What is a controlled load?
Controlled load is a separate circuit, often for hot water, charged at a different rate and controlled by the network.
Is flat-rate or time-of-use better?
It depends on when you use electricity. Solar, battery and EV charging can change which tariff is more suitable.
Should I change retailer after installing solar?
It may be worth comparing plans because feed-in rates, usage rates and supply charges vary between retailers.
Can a high feed-in rate be misleading?
Sometimes. A plan with a high feed-in rate may also have higher usage or supply charges. The whole bill needs to be checked.
Can demand tariffs apply to homes?
Some residential customers may be moved to tariff structures that include demand-style components, depending on network and retailer arrangements.
Bill Review Process
What customers should expect when submitting a bill.
What documents do I need for a bill review?
A recent electricity bill is the best starting point. If available, smart meter interval data and solar monitoring screenshots can improve accuracy.
What information should I provide with the bill?
Tell us whether you have solar, battery, EV charging, pool pump, electric hot water, business equipment, and what outcome you want to achieve.
Do you need my NMI or account number?
The bill may contain these details. We use bill information only to understand tariff, usage and charges for the review.
How long does a bill review take?
Timing depends on enquiry volume and bill complexity. Simple residential reviews are usually faster than commercial demand-charge reviews.
Will I receive a quote after the review?
If solar, battery, EV charging or peak-shaving options appear suitable, we can discuss next steps and prepare a suitable proposal.
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