Solar fences: vertical bifacial PV explained

A solar fence is a line of bifacial PV modules mounted vertically, standing upright at about 90 degrees on a galvanised steel and aluminium structure, usually facing east and west so one face catches the morning sun and the other the afternoon. Because it stands like a fence rather than tilting like a roof array, it takes almost no snow load, sheds rain and leaves the ground beneath it clear for crops, machinery or a path. This guide explains how a solar fence works, where it suits, and how the mounting structure is built. For the tilted alternative see our guide to ground-mount PV systems.

What a solar fence is

A solar fence is a vertical array. Bifacial modules, which generate from both faces, are held upright between posts so the panel plane stands vertical instead of tilting to the sky. Mounted east to west, the two faces of each module look toward sunrise and sunset. The structure is essentially a strong fence line built to carry glass rather than mesh, so it borrows the logic of both a PV mounting system and a boundary fence. ULAMEX supplies the mounting structure, the posts, profiles and fixings, not the bifacial modules or the electrical parts.

How a vertical array generates

A vertical east-west array has a different output shape from a tilted south-facing one. Instead of a single midday peak, it produces two gentler peaks, one in the morning as the east face is lit and one in the late afternoon as the west face is lit. This spreads generation across the day and can better match demand and grid needs at the shoulders of the day. Field studies of vertical bifacial systems report yields per kilowatt-peak that can reach roughly ten percent above a conventional south-facing array, though the exact figure depends on the site, the albedo and the modules.

Why vertical, and why bifacial

The vertical stance brings practical gains beyond the output curve. A vertical panel sheds snow and does not hold a snow load, which matters in continental winters, and it collects far less dust than a tilted panel, so it stays cleaner. Rain running off keeps the glass washed. Bifacial modules are used because a vertical panel would waste half its potential if only one face worked, and the reflected light from ground, snow or a light surface behind the array lifts the rear-face yield. Together, vertical and bifacial turn a fence line into a generating surface.

Solar fences in agrivoltaics

The clearest use is on farmland. Because the modules stand in a narrow vertical line, a solar fence casts only a thin moving shadow and leaves the land between rows open for crops or grazing, which is the idea behind agrivoltaics. Rows are set along field boundaries or between crop strips, so the ground keeps producing food while the fence produces power, and machinery can pass between the rows. Crops that tolerate a passing shadow, such as grass for hay or low field crops, suit the layout well, and the vertical line doubles as a stock or boundary barrier.

Solar fences as boundaries

A solar fence also earns its place as a boundary in its own right. Along the edge of a commercial yard, a car park or a large garden, it marks and secures the perimeter while generating, so a structure that would otherwise only divide space now pays its way. Used this way it sits close to a conventional fence in look and function, which is why the mounting borrows from fencing practice: strong posts on proper foundations, at a spacing set by the module and the wind. For a non-generating boundary see our guide to modern aluminium fencing systems.

The mounting structure

The structure is a run of posts carrying horizontal rails that clamp the modules top and bottom. The posts are the load-bearing members, set on foundations, and are galvanised steel where strength and economy matter, while the rails and module clamps are EN AW-6060 T6 aluminium at the exposed surface so they do not corrode. The clamps are the same mid and end clamps used across PV mounting, sized to the module frame. Building the fence in these metals, galvanised steel posts carrying aluminium rails, gives a structure that lasts the twenty-five-year-plus life of the modules.

Height, spacing and layout

A solar fence is laid out like a fence and generates like an array, so both logics shape it. The module height sets the height of the line, usually one or two modules stacked, and the ground clearance beneath keeps the lowest edge clear of splashing soil and growing crops. Post spacing follows the module width and the wind load, in the same way a boundary fence is spaced to its panel. Where rows are repeated across a field, the spacing between rows is set so one line does not shade the next in low sun, the same pitch calculation used for a tilted ground array. Setting the height, the post spacing and the row pitch together is what makes the fence both stable and productive.

Installing a solar fence

The build follows fencing practice with an array on top. The posts go in first, set on rammed piles, ground screws or concrete footings, plumb and on a true line, because everything above depends on straight, well-founded posts. The horizontal rails are then fixed across the posts, and the bifacial modules are clamped to the rails top and bottom with the same mid and end clamps used across PV mounting. The direct-current cabling is clipped along the structure and run to the inverter by the installer. Because there is no tilt frame to set, a vertical fence is quick to assemble once the posts are true, and it needs no roof penetration at all.

Foundations and wind load

A vertical panel is a solid sail, so wind is the load that governs a solar fence. The full face of the array catches the wind, which drives the post size and, above all, the foundations. Posts are set on rammed piles, ground screws or concrete footings, sized so the line does not lean or lift in a gust, and in colder ground the footing reaches below the frost line. The wind load is calculated to the Eurocode, EN 1991-1-4, for the exposure of the site, because an open field carries far more wind than a sheltered boundary. Getting the foundations right is what keeps a solar fence standing.

Maintaining a solar fence

A solar fence is one of the lower-maintenance ways to mount PV. Standing vertical, it sheds snow entirely and holds no snow load, and rain running down the glass keeps both faces washed, so cleaning is rarely needed except where soiling is heavy. The mounting checks are the same as any array: the clamps stay tight to the correct torque, the posts and rails stay secure, and the galvanised and aluminium parts show no corrosion, with any bare cut edge on a galvanised part re-protected. Because the structure is built in aluminium, stainless and galvanised steel, and because the vertical stance keeps it clean and snow-free, the routine is a periodic visual check rather than regular work. The electrical side, from the module connections to the inverter, belongs to the installer, and is the only part of a solar fence that needs a qualified hand rather than a periodic look.

Where a solar fence fits, and where it does not

A solar fence is not a replacement for a roof or a tilted ground array on every site. It gives up some peak yield for its spread output, uses more structure per module than a tilted table, and needs bifacial modules and a clear east-west line to work well. It comes into its own where land is shared with farming, where a boundary has to be built anyway, or where the morning and afternoon output shape suits the load better than a midday peak. Matching the layout to the site is what decides whether a vertical fence or a tilted array is the better answer. As a rule, a solar fence is strongest where a boundary or a field division has to exist regardless, so the generation is won on structure that would have been built anyway, and weakest where open ground could simply carry a cheaper tilted array. Weighing the extra structure per module against the shared use of the land, and against the more even output, is the calculation that settles it for a given project.

Solar fence structures from ULAMEX

ULAMEX manufactures PV mounting and fencing structures under EN 1090 and has supplied the trade since 1988.

Planning a solar fence? Send the run length, module type and site, and ULAMEX will return a non-binding quotation with lead time and availability. Browse the photovoltaic mounting range, read the full PV mounting systems guide, or view our supply capabilities. Contact the export desk at [email protected] or +48 504 424 761.

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