For co-located sites, you can choose how unclipped solar generation is handled. This controls whether the model treats solar and battery as independent assets, or optimises them together.
These strategies apply to both AC and DC coupled sites. On DC-coupled sites, clipped solar can always flow to the battery regardless of which strategy is selected.
Always export solar
The simplest option: all solar generation is exported to the grid as it is produced.
- Solar revenues are based on the half-hourly wholesale power price at the time of generation
- The battery operates entirely independently - it charges and discharges based on price signals alone, without regard to what solar is doing
- A good baseline for understanding the standalone value of each asset
Export when prices are positive
Solar is still exported directly, but the model holds back generation during negative price periods rather than paying to export.
- When wholesale prices turn negative, solar generation is curtailed
- The battery still runs independently of the solar asset
- This reflects the behaviour of many real assets, which are not obligated to export during negative prices
Optimise with battery
The model treats the solar asset and battery as a single integrated system, and finds the combination of export, battery charging, and curtailment that maximises total site revenue.
- Solar generation can charge the battery rather than being exported immediately
- There is no fixed rule about when solar must be exported - the model decides based on current and forecast prices
- This allows solar generation to be ‘time shifted’ to more valuable periods
This strategy typically produces the highest revenues, because the model has the most flexibility to respond to price signals across both assets.
Comparing the strategies
The chart below shows how each strategy handles solar generation over three days:
- Optimise with Battery (top): Solar charges the battery (blue) or is curtailed (red) during low-price periods, shifting generation to higher-value times
- Always Export (middle): All unclipped solar is sold immediately - no curtailment, no battery charging from solar
- Export when Positive Prices (bottom): Solar is curtailed only when prices go negative, avoiding revenue losses from exporting at a cost
The day-ahead price (yellow line) illustrates how differently each strategy responds to the same price signals.