Minimising curtailment and maximising feed-in tariffs with export-limited rooftop solar

If you have a large solar system and regularly export a lot of your generation, or only have relatively small EV charging loads which are readily met with solar charging you may look at ways to reduce the curtailment caused by export limits.

The less time your solar output is curtailed, the more production you have, which reduces fossil fuel use in grid generation and may earn additional credits from feed-in tariffs.

Whilst Charge HQ will automatically utilise solar production that may have been curtailed due to export limits, it won’t optimise your charging to also maximise your exports. There are some steps you can take though.

To minimise curtailment you want to align any flexible loads such as EV and home battery charging to occur with periods that would otherwise be curtailed.

A few options are presented that need to be adapted to your individual circumstance. They may also need adjusting as your solar generation varies with the seasons.

1. Set Min Solar Generation to say 5 kW. In our example above with a 10 kW solar system with a 5 kW export limit, this would stop your EV from charging at the start and end of the day when solar production is low and concentrating charging to periods where it may be otherwise curtailed.
2. Set Blockout periods from 6 am to 10 am and 4 pm to 8 pm. This will override solar tracking and prevent EV charging from occurring before 10 am and after 4 pm. Similar to option 1 but using time-clock based constraints.
3. Set your Max Charge Amps to say 5 kW. Again using our example system above, a 10 kW system with 5 kW of EV charging should never be exporting more than 5 kW allowing for some minimal home loads. By using a slightly reduced charging speed your EV charging will be spread out over a longer period of the day, reducing the period the export limit may apply.