Questions, answered carefully.
Four short explainers — the same logic that drives the calculator.
Self-consumption — the real win
Self-consumption is the share of solar you actually use in your own home instead of exporting to the grid. Every self-consumed kWh saves you the full retail rate; every exported kWh earns only the feed-in tariff. The economics of every modern solar setup are driven by this gap.
Why batteries matter
A battery isn't a money-maker — it's a self-consumption upgrade. It stores the solar you'd otherwise export at a low feed-in rate and releases it in the evening when you'd otherwise buy from the grid at full retail. The case is strongest for evening households.
What VPP-ready really means
VPP-ready means the hardware (typically a hybrid inverter plus a compatible battery and comms) is capable of joining a Virtual Power Plant program later. It does not commit you to a program, and it does not promise a payment. Programs vary by retailer and region, and terms change.
Why this is a preliminary estimate
Fishleg Calculator is a pre-sales tool, not engineering software. We use transparent state-level defaults for sun-hours and tariffs, your inputs for usage and roof, and deterministic formulas you can audit. A real proposal still needs a site assessment, network rules, and approved hardware selection.