Path-Q Solar
How can I tell whether solar output is meeting the original estimate?
Answer
Compare measured production with the original model using the same period, system boundaries, and assumptions, while adjusting for actual weather, shading, soiling, outages, and equipment changes. A fair assessment uses longer periods and weather-adjusted expectations rather than comparing one raw bill or month with the estimate.
Key points
- Identify whether the estimate was annual, monthly, or based on modeled hourly production.
- Compare actual generation, not just bill savings, because consumption and utility billing can change independently.
- Account for commissioning delays, outages, degradation, new shading, and meter or monitoring errors.
What it depends on
- Original proposal and production model
- Actual irradiance, temperature, snow, shading, and soiling
- System availability and equipment changes
- Accuracy and time resolution of production records
Risks and trade-offs
- A proposal estimate may use assumptions that are not directly comparable with actual conditions.
- Bill savings can differ from production because of consumption timing and billing rules.
- A shortfall may require technical investigation before any performance claim is made.
Information you may need
- Original modeled production by month or year
- Complete production data and outage records
- Weather, shading, soiling, and system-change history
Your next step
What to do next
Request the original production model and create a weather-adjusted comparison over at least a meaningful operating period before escalating a performance concern.
Path-Q
Find the right next step
Answer a few questions and we’ll narrow your options.
Loading…
SQ00862