Energy flow (grid-tied)

What gets simulated

At each time step the simulator works out a strict priority order for the available solar power. Load is served first (self-consumption). Any remainder either tops up the battery, exports to the grid, or — if the battery is full and the export window is closed — is curtailed (dumped). When solar plus battery can’t meet load, the shortfall is covered by grid import.

The battery is modelled with a real-world round-trip efficiency, a minimum reserve, and a maximum charge / discharge rate. Cycling decisions take the price signal into account: the simulator looks one day ahead so it can preserve battery for an upcoming peak-priced window instead of wasting it on a cheap-export hour now.

What each series means

• Solar (orange filled area) — the instantaneous solar production from your panel groups, after temperature derate and system efficiency.
• Load (black line) — the modelled household / site demand at that time of day.
• Battery charge (blue line, right axis), in kWh. Bounded by your battery’s usable capacity and the configured minimum reserve.
• Grid export (green line) — surplus solar (or, with the bonus-discharge strategy, surplus battery) being sent to the grid.
• Grid import (red line) — power drawn from the grid to cover the deficit.
• Curtailed (dashed purple, only when present) — solar that couldn’t be consumed, stored, or exported, so it’s clipped at the inverter.
• EV charge (cyan, only on Charge-EV strategies) — power being delivered to the EV at that moment.

Background bands

Amber background bands mark the peak-priced windows in the tariff — any grid import landing inside an amber band costs the most per kWh, and any export pays the most. Light-blue bands mark a no-export window (proxy for negative wholesale prices); during those hours surplus solar is curtailed rather than fed back to the grid.

The faint amber band around the solar curve is the forecast uncertainty. It’s symmetric (real weather can surprise either way) and widens with how far ahead the date is — today’s band collapses to a point because the day’s weather is already in. The band is clamped on the lower side at the maximally-cloudy day’s diffuse-only floor (≈ 10 % of clear-sky) and on the upper side at clear-sky production, so the visualisation never claims a number outside what physics allows.

Strategy effect

The chosen export / EV strategy changes what we do with your spare solar and the battery:

• Default export — run the house on your own solar first; the battery sells into the evening peak when it can spare the charge and still cover tomorrow.
• Maximise charge — keep the battery topped up for outage resilience. Solar surplus only exports during peak-priced windows; otherwise it’s curtailed.
• Charge EV — surplus solar fills the battery, then routes to the EV during the charging window. Bonus battery → EV transfer fires when the forecast predicts later curtailment, but only above tomorrow’s reservation. Never exports to the grid.
• Charge EV (max) — maximises EV charge by draining the battery into the EV down to its hardware-safe minimum during the window. May import overnight if tomorrow’s solar disappoints. Never exports.