Azimuth is the compass orientation of a PV array, measured from true north (0°) clockwise to 360°. South-facing (180°) is optimal for annual energy in the northern hemisphere; deviations cost yield but may align with tariff incentives.
Quick Facts
| Field | Detail |
|---|---|
| Term | Azimuth |
| Category | Solar Engineering / Design |
| Units | Degrees from true north (0–360°) |
| Convention | 0° = N, 90° = E, 180° = S, 270° = W |
| Difficulty Level | Beginner |
What is Azimuth?
Azimuth is the compass orientation of a PV array, measured clockwise from true north. It determines when during the day the array receives peak irradiance.
Common azimuths (northern hemisphere)
- 180° (due south) — Maximum annual energy.
- 135° (SE) / 225° (SW) — ~96% of due-south production.
- 90° (E) / 270° (W) — ~80–85% of due-south production.
- 0° (N) — ~50% or less.
NEM 3.0 Implications
In California under NBT (NEM 3.0):
- Midday export rates: $0.02–0.08/kWh.
- Evening (4–9 PM) export rates: $0.20–0.80/kWh.
A west-facing module generates more in the high-priced evening window, potentially producing 10–20% higher revenue per kWh despite ~10% lower annual production. Mixed east-west designs balance morning and evening production.
Engineering Deep Dive
POA reduction by azimuth deviation
For a 30° tilt at 30°N latitude:
| Azimuth | Annual POA % |
|---|---|
| 180° (S) | 100% |
| 165° / 195° | 99.5% |
| 150° / 210° | 98% |
| 135° / 225° | 96% |
| 120° / 240° | 92% |
| 90° (E) / 270° (W) | 82–85% |
| 60° / 300° | 70–73% |
| 0° (N) | 45–55% |
True vs. magnetic north
Always use true north. Magnetic declination varies by location and time (±20° in some areas). Use a GPS-based true-north tool or solar pathfinder.
Multiple orientations
For rooftops with two azimuths (east + west, common on gable roofs):
- Use 2+ MPPT inverter.
- Each MPPT covers one orientation.
- Microinverters per module are an alternative.
Permitting Implications
Azimuth must be shown on the site plan and SLD. PE-stamped designs include azimuth verification per orientation.
Best Practices
- Use a smartphone compass (with magnetic-to-true correction) or GPS for site survey.
- For mixed orientations, allocate separate MPPTs or microinverters.
- Run PVsyst sensitivity by ±15° to validate the chosen azimuth.
- In NEM 3.0, model west-facing yield separately for export-value optimization.
Key Takeaways
- Azimuth is the compass orientation of a PV array; south (180°) optimal in the northern hemisphere.
- Yield drops as azimuth deviates from optimal — 10° deviation costs 1–2%, 45° costs 4–6%, 90° costs 15–18%.
- NEM 3.0 California shifts the economic preference slightly westward (high evening export rates).
- Mixed-orientation arrays need multiple MPPTs or microinverters.
- Always use true north (correct for magnetic declination).
Frequently Asked Questions
8 commonly searched questions about Azimuth.
What is azimuth?
What's the yield penalty for non-south orientation?
Should I prefer west-facing in NEM 3.0?
Can a PV array face north?
How does azimuth affect bifacial?
What azimuth for trackers?
Does azimuth affect inverter sizing?
What if my roof has multiple azimuths?
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