Path-Q Solar
How should curtailment of exported solar affect projected bill savings?
Answer
Curtailment should be modeled as potential solar output that is prevented from being generated or delivered because it cannot be exported, used on site, or stored. That unrealized production has no bill value. The estimate should separately report self-consumed energy, stored energy, exported energy, and curtailed potential output by time period.
Key points
- Curtailment reduces the effective value of additional solar production.
- It can occur because of export limits, control settings, grid conditions, or an undersized interconnection.
- Storage or load shifting may recover some otherwise curtailed energy, subject to losses and capacity.
- Curtailment assumptions should be based on system controls and export rules, not a generic annual percentage.
What it depends on
- Export limit and interconnection arrangement
- Hourly load and solar production
- Battery capacity and dispatch rules
- Inverter control behavior
- Applicable utility or grid operating requirements
Risks and trade-offs
- Ignoring curtailment can overstate savings and system value.
- Oversizing the array may improve production in weak-sun periods but increase midday curtailment.
- Adding storage to avoid curtailment may cost more than the recovered energy is worth.
Information you may need
- Export limit and control requirements
- Hourly production and load profiles
- Curtailment history or modeled frequency
- Storage and load-shifting assumptions
Your next step
What to do next
Ask for an hourly production-and-bill model that explicitly reports self-consumption, exports, stored energy, losses, and curtailed energy.
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SQ01901