Project Overview
When a large-scale vegetable farm in Eastern Europe approached us about a 2 MW agrivoltaics installation, the brief was straightforward on paper: generate solar energy from land already in active agricultural production without removing a single hectare from the crop rotation. The reality was considerably more complex.
The farm operates row-crop production on flat, open terrain with full mechanized harvest cycles. Standard ground-mount racking — with panel bottom-chord heights of 0.8 m to 1.2 m above grade — was immediately ruled out. The site requires full-size tractor clearance, including combines and articulated sprayers with overhead booms reaching up to 3.8 m. The project target was a minimum usable clearance height of 4.0 m under the lowest structural chord, across the entire array footprint.
That single requirement — 4 m of unobstructed working height — cascades through every dimension of the structural design: column height, foundation depth, cross-bracing geometry, wind load resistance, and installation sequencing. This case study documents how we engineered the system, specified materials for a C3 inland agricultural environment, and executed installation within the farm's seasonal windows.
The Structural Challenge: Elevated Canopy Design
The fundamental structural problem with a high-clearance agrivoltaic canopy is one of bending moment. Wind acts as a lateral force on the panel array; the column resists that force as a cantilever. The bending moment at the column base equals the lateral force multiplied by the effective height. Every additional meter of column height multiplies the base moment by the same factor — a column at 5 m effective height carries roughly 40% more base moment than one at 3.5 m for an identical wind pressure.
On this project, the panel array is mounted at a nominal height of 4.5 m to bottom chord, with panel top chord reaching approximately 5.5 m at the high side. The design basic wind speed for the site is 28 m/s (per the relevant national standard, equivalent to ASCE 7-16 Exposure Category B). At 5.5 m effective height, the design uplift and drag forces on each panel row produce column base moments approaching 45 kN·m under governing load combinations — a value that would require substantially oversized sections if the column were a simple vertical cantilever.
The solution is a combination of three load-path strategies:
1. Y-brace intermediate portal frame. Pairs of columns in each transverse row are connected by a knee-brace welded at approximately 40% of column height. This converts the cantilever into a braced frame, reducing effective cantilever length and redistributing base moment into the brace connection and the adjacent column.
2. Longitudinal tension cable cross-bracing. Pre-tensioned 12 mm galvanized wire rope runs diagonally between column tops in the longitudinal direction. This system absorbs longitudinal wind drag forces that would otherwise accumulate across the full array length and overload end-column foundations. Turnbuckle tensioners at each anchor allow field adjustment to the correct pre-tension level.
3. Column section sizing via SAP2000 analysis. We modeled the full array in SAP2000, applying ASCE 7-16 wind load combinations across the panel surface area. The analysis confirmed that 180×180×8 mm HSS square tubular sections in S355 structural steel provide utilization ratios below 0.85 at all member locations under governing load combinations — leaving adequate reserve for the site's occasional heavy agricultural vehicle impact loads. For a deep technical look at how wind load calculations drive racking design decisions, see our guide: What Is a Wind Load Calculation — and Why You Should Never Accept a Solar Racking System Without One.
Foundation Design: Ground Screws Over Concrete
The choice of foundation for an active farmland site is not primarily a structural decision. It is a logistics and reversibility decision, and on this project those criteria pointed unambiguously to helical ground screws (driven piles).
Concrete strip or pile foundations require heavy equipment access to deliver and place concrete, curing time of 7–14 days before structural loading, and permanent ground modification that complicates any future land-use change. On an active farm, concrete truck access across planted or prepared crop rows is operationally disruptive and in some cases destructive.
Ground screws, by contrast, are driven by a hydraulic torque head attachment on a compact excavator or dedicated screw-drive machine. The footprint of the installation equipment is small enough to operate between established crop rows. There is no cure time: the column can be bolted to the anchor plate the same day the screw is driven. At end of project life, screws are reversible — they can be extracted and the land returned to full agricultural use.
For this site — silty loam with clay subsoil, groundwater table at 2.2 m depth — we specified 114 mm diameter hot-dip galvanized screws with 400 mm helical blade, driven to a target installation torque of 14 kN·m. The torque-to-capacity correlation for this soil profile, confirmed by pre-construction probe testing, yields a factored pull-out capacity exceeding 120 kN per screw — well above the governing uplift demand of 68 kN under the ASCE 7-16 design wind event.
For a comprehensive comparison of ground screw versus concrete foundation performance, cost, and geotechnical considerations, see our earlier analysis: Ground Screw vs. Concrete Foundation: The Structural Case for Helical Piles in Utility-Scale Solar.
Column and Cross-Brace System
Each primary column is a 180×180×8 mm HSS square section, 5.8 m overall length, with a baseplate flange welded at grade for bolted connection to the ground screw anchor plate. The knee-brace members are 120×120×6 mm HSS sections, set at 45° to the column axis, connecting at the 2.3 m height point. This geometry produces the Y-brace profile characteristic of Solaracks' high-clearance agrivoltaic product range.
At the column top, a fabricated saddle bracket accepts the main purlin — a 160×80×5 mm rectangular HSS running the full longitudinal array length — and the tension cable anchor lug. The saddle bracket is slotted to allow ±5° panel tilt adjustment during installation, accommodating minor deviations in ground screw plumb without requiring column re-driving.
Column pairs are spaced at 5.0 m in the transverse direction and 5.5 m in the longitudinal direction, producing a bay grid that accommodates two standard 2,094×1,038 mm panels in portrait orientation per bay, with appropriate inter-panel gap for thermal expansion and cleaning access.
The longitudinal tension cable system runs at two levels: at the column top chord (primary wind bracing) and at mid-height on the knee-brace (secondary bracing for longitudinal racking stability during panel installation). Each cable is 12 mm 7×19 stainless wire rope, anchored to purpose-designed fork-and-pin connections at the column head and tensioned to 8 kN pre-tension via M24 turnbuckles. This system achieves full longitudinal rigidity without welded cross-frames that would complicate installation and restrict tractor access paths between column lines.
Panel Layout and Shading Design
The agrivoltaic value proposition depends on getting the inter-row gap and tilt angle right. Too little gap produces full shade and suppresses crop yield. Too much gap wastes the structural cost of elevated mounting without meaningfully increasing irradiance.
For row crops — in this case mixed leafy vegetables — the design target is 30–50% light transmission to the crop canopy. Research on light-demanding field vegetables indicates that yields are maintained at this partial shading level, while water stress is measurably reduced through panel evapotranspiration cooling effects.
We specified a 15° panel tilt angle with 4.8 m inter-row pitch. At this geometry, modeling shows peak shade coverage of 42% at solar noon in midsummer, falling to approximately 22% average daily coverage accounting for morning and evening sun angles. The dappled light pattern under the array is dynamic throughout the day, which mitigates the concentrated shade stress that would occur with fixed full-shade coverage.
An east-west orientation of the panel rows was evaluated as an alternative. E-W configuration produces a more uniform daily shade pattern — because both sides of the roof receive morning and afternoon irradiance respectively — and eliminates the pronounced midday shade band of south-facing rows. For this project the client retained a south-facing layout to maximize annual energy generation, but E-W layouts are appropriate where shade uniformity is the primary agronomic constraint, such as fruit orchards or vine crops with strict irradiance thresholds.
Material Specification for the Agricultural Environment
The site is classified as ISO 9223 corrosivity category C3 — inland location, moderate humidity, no marine salt influence, low industrial pollution. This classification drives the full material specification stack.
Structural steel: All HSS columns, knee-braces, and purlins are hot-dip galvanized (HDG) to ISO 1461, with minimum average coating thickness of 85 µm. For a C3 environment with a 25-year service life target, HDG ISO 1461 is the appropriate minimum standard and provides substantial over-specification relative to zinc loss rates typical of C3 sites (approximately 2–4 µm/year).
Ground-line fasteners: The transition zone between the column baseplate and the ground screw anchor plate is the most vulnerable connection on the system. Soil contact, condensation cycling, and the presence of fertilizer residues create a locally elevated corrosion environment compared to the above-grade structure. We specified 316L stainless fasteners for all below-grade and ground-line connections, and EPDM isolation washers at every aluminum-to-steel interface on the above-grade structure to eliminate galvanic contact.
Purlin-to-panel interface: The purlin system uses 6005-T5 aluminum alloy rails with pre-assembled mid-clamps and end-clamps. All rail-to-purlin contact interfaces use EPDM insulation strips to prevent direct aluminum-to-steel contact and the galvanic corrosion path that contact creates in the presence of agricultural moisture.
For a complete guide to material selection across corrosivity categories, including C3, C4, and C5 coastal environments, refer to our SolarMaterialFacts corrosion series.
Installation Sequencing on an Active Farm
A 2 MW agrivoltaic array on active farmland cannot be installed using a conventional utility-scale construction schedule. Continuous site occupation with heavy equipment would destroy crop rows and prevent the seasonal cultivation cycle. We designed the installation sequence around the farm's 6-week inter-season window between harvest and the next planting preparation.
Phase 1 — Ground screw driving (weeks 1–2). A compact 5-tonne excavator fitted with a hydraulic torque head drove all 320 ground screws in sequence along pre-surveyed alignment strings. The machine tracked along designated access corridors between crop rows, leaving adjacent rows undisturbed. Torque was logged per screw and any failing-torque screws were flagged for re-positioning at installation day, avoiding delay in subsequent phases.
Phase 2 — Column and brace erection (weeks 2–4). Pre-assembled column-plus-knee-brace units arrived at site as factory-fabricated weldments, with baseplate and brace connection pre-drilled. Telescoping section design — the lower column slides into and bolts to the upper section — allowed two workers to erect each column unit without crane assistance. A small rough-terrain telehandler positioned the upper purlin runs along each row. Longitudinal cable bracing was installed and tensioned row by row before moving forward.
Phase 3 — Panel installation (weeks 4–6). Panels were installed from the side of each row using a panel-lift attachment on the telehandler, feeding modules horizontally into the clamp system from ground level. No overhead access or scaffolding was required. The wide inter-row gap provided full lateral access along the entire length of each row.
At the end of the 6-week window, the farm returned to full cultivation with the array complete and energized.
Results and Outcomes
The installed system confirms the dual-use premise:
- Tractor clearance: The as-built clear height under the lowest structural element (knee-brace bottom) measures 4.2 m across all array zones — exceeding the 4.0 m design minimum and accommodating the client's largest agricultural machinery.
- Energy generation: The 2 MW array produced 2,680 MWh in its first full operational year, consistent with the modeled specific yield of 1,340 kWh/kWp for the site's irradiance and system losses.
- Crop yield: First-year vegetable yield data from the area under the array showed no statistically significant reduction compared to the adjacent non-shaded control plots at equivalent crop density. The partial shading effect measurably reduced irrigation demand during the site's dry summer period.
- Structural performance: The array experienced three wind events exceeding 22 m/s gust speed in its first year of operation. Post-event inspections confirmed no structural movement, no cable slack, and no fastener loosening across the full array.
The project demonstrates that agricultural land-use continuity and commercial-scale solar generation are compatible at the 2 MW scale when the structural system is designed with equal care for the farming operation as for the PV system performance.
How Solaracks Supports Agrivoltaic Projects
Solaracks' high-clearance ground mount system is designed as an integrated product offering: helical ground screws, Y-brace column assemblies, pre-tensioned longitudinal cable bracing, and aluminum purlin rail — all specified and supplied as a coordinated system, not an assembly of generic components.
For each project, we provide SAP2000 structural analysis of the elevated canopy under site-specific wind and snow loads, along with a full load calculation note per ASCE 7-16 or JIS C 8955:2017. Quote and preliminary design turnaround is 24 hours from receipt of site data — latitude, basic wind speed, soil type, and panel model.
If you are developing an agrivoltaics project and need a mounting system that keeps the land fully in production, contact us to discuss your site requirements. We are ready to support you.