Azimuth

Answer: Azimuth is a horizontal direction expressed as an angle from a stated reference. With a true-north, clockwise convention, north is 0°, east 90°, south 180° and west 270°, in either hemisphere. For solar design, distinguish the direction the array faces from the sun’s changing direction, and check the software convention before entering or transferring an angle.

Array azimuth, solar azimuth and tilt

A fixed array has an orientation; the sun has a position that changes with location, date and time. Array azimuth describes the horizontal direction toward which a tilted module surface faces. Solar azimuth describes the sun’s horizontal direction. They are different inputs, even when their angles happen to match.

Tilt angle describes the surface’s inclination from horizontal. Azimuth and tilt together affect the angle of incidence. A horizontal surface does not have a unique facing direction: rotating it horizontally leaves its plane unchanged. For trackers, an azimuth input may instead describe the rotation axis. Check the selected tracking mode rather than treating it as fixed-panel orientation.

State the convention before sharing a number

The north-clockwise convention gives these bearings everywhere:

However, PVsyst uses a different solar convention: its northern-hemisphere reference is south, with positive angles toward west; in the southern hemisphere its reference is north, also positive toward west. Its solar geometry documentation states both reference and sign. PVsyst solar geometry.

Hypothetical northern-hemisphere transfer: an array bearing of 240° in a north-clockwise system is +60° in a south-zero, west-positive system. Due east is 90° in the first system and −90° in the second. This conversion is specific to those conventions; do not apply it unchanged to a southern-hemisphere project or a different software definition.

SAM/PVWatts documents north-clockwise bearings for both hemispheres and distinguishes fixed-array orientation from tracker-axis orientation. SAM system design.

Does south always produce the most energy?

Equator-facing orientation is a useful starting point for many fixed arrays: south north of the equator, north south of it. It is not a universal optimum. Compare feasible orientations using the project’s weather, tilt, obstructions, available area, mounting and electrical configuration. Near the equator, seasonal sun position also makes a simple hemisphere rule less useful.

East-facing and west-facing planes can shift generation toward different parts of the day. Their annual output is not a fixed percentage of an equator-facing plane. Likewise, a north-facing roof is not automatically unsuitable. A shallow roof and a steep roof require different comparisons.

Energy yield and financial value are separate objectives. To compare tariff value, use time-matched generation, consumption, import/export prices and any storage assumptions. A west-facing layout does not necessarily earn more: afternoon output may not coincide with the relevant tariff interval, particularly near sunset. Do not substitute an orientation label for an hourly assessment.

Practical checks for project teams

• Designers: record the reference, sign, units, tilt and source for each plane. Verify imagery orientation and survey references. A magnetic compass bearing needs a location- and date-appropriate declination correction; nearby magnetic interference is a separate concern. NOAA magnetic declination.
• Installers: compare the installed planes and tracker axes with the issued design. Record changes in as-built drawings. Different orientations do not automatically require different MPPTs in every architecture; check manufacturer rules and the actual electrical model.
• Sales teams: show a site-specific comparison with consistent assumptions, rather than a guaranteed east/west output or savings percentage. Separate measured orientation from modeled energy and estimated financial outcomes.

Use the solar zenith and azimuth explanation for sun-position geometry. To evaluate the orientation inputs and evidence your team needs from a design workflow, book a SurgePV demo.

Frequently asked questions

Is 180° always south?

It is south in a north-clockwise bearing system. It is not the south-facing input in a south-zero system. Always include the convention.

Is azimuth measured from true or magnetic north?

Solar modeling commonly uses a geographic reference. A compass measures the local magnetic direction, so confirm and correct its reference before transferring the reading. Do not apply a fixed global declination.

Can east, west or north-facing panels work?

Yes, but suitability depends on the site, tilt, shade, equipment and economics. Compare realistic layouts without assigning a universal output ratio.

Does solar azimuth tell me when the sun sets?

It gives the sun’s horizontal direction at a specified place and time. Sunset direction varies through the year and with location; west is not a universal sunset bearing.