1P Horizontal Single-Axis Tracking System

Product Overview

The 1P (One-in-Portrait) Horizontal Single-Axis Tracking System is the industry-standard tracker architecture for utility-scale PV plants on flat to gently rolling terrain. By rotating each row of modules east-to-west throughout the day to follow the sun's azimuth, this system captures 20–28% more annual energy than an equivalent fixed-tilt installation — a gain that directly improves project IRR, reduces LCOE, and strengthens PPA competitiveness.

This system is designed for scale. Each tracker row accommodates 60–120 modules in 1P configuration (modules in portrait orientation on a single torque tube), driven by a centralized slew-drive motor at the row center. The system's 2P variant doubles module count per row to 120+ modules for ultra-high-density layouts.

Key engineering features:

Slew-drive actuator (not linear actuator/push-rod): The slew drive provides continuous 360° rotation capability with high torque density and zero backlash, suitable for the high-cycle fatigue environment of daily solar tracking (9,000+ cycles over 25 years)

±0.5° tracking accuracy: Closed-loop control via inclinometer feedback, not open-loop time-based positioning that drifts without correction

Astronomical algorithm + backtracking: The controller calculates sun position from GPS coordinates and date/time, with backtracking logic that flattens rows during low sun angles to eliminate inter-row shading

Q355B galvanized steel torque tube with C4 corrosion protection: Sized per row length and local wind load for torsional stiffness that prevents row twist and module misalignment

Energy Yield: Tracker vs Fixed Tilt

Technical Specifications

Applications

Flat-terrain utility PV farms (10MW)

High-DNI regions (MENA, South Africa, Chile, Australia, US Southwest, India)

Large-scale IPP and government tender projects

Sites where land cost justifies higher GCR

Engineering Workflow

Site topography analysis: Maximum N-S slope grade verified (<5% for standard design; >5% requires terraced row adaptation)

Wind tunnel load coefficients: Cp values for the specific module geometry at all tracker angles, per wind tunnel testing or CFD analysis

Torque tube sizing: Torsional stiffness calculation to limit row twist to <1° under design wind, preventing module misalignment and glass stress

Foundation design: Lateral load and overturning moment verification per EN 1997-1, accounting for the dynamic load amplification from tracker movement

Row spacing optimization: Backtracking algorithm simulation across the full year to determine minimum row pitch without shading loss

Installation Process

Case Study: 80MW 1P Tracker Project — Northern Cape, South Africa

Challenge: Flat semi-desert terrain with high DNI (2,200+ kWh/m²/year). Project requirement for 25% yield gain over fixed tilt to meet PPA financial model. Wind gusts to 35 m/s during summer thunderstorm season.

Solution: 1P horizontal single-axis tracker, Ø219mm torque tube, slew drive, astronomical algorithm with GPS syncing and backtracking enabled. Q355B HDG steel, C4 coating. Driven pile foundation. 90 modules per row, 2×45 portrait. Auto-stow wind protection triggered at 25 m/s.

Result: Measured 26.4% annual yield gain over fixed-10° benchmark installation at same site. Zero row-to-row shading losses confirmed by on-site pyranometer measurement. Wind stow events averaged 12 per year; zero structural or drive damage after 3 years of operation.

FAQ

Q. What is the payback period for tracker vs fixed tilt?

For a high-DNI site (2,000+ kWh/m²/year), the tracker premium (\$0.04–0.07/Wdc) typically pays back in 3–5 years through increased energy revenue. This is heavily site-dependent — at lower DNI sites (<1,500 kWh/m²/year), the payback extends to 6–8 years, and fixed tilt may be more appropriate.

Q. How does backtracking work and why is it necessary?

During early morning and late afternoon when the sun is low, the front row would cast a shadow on the row behind it. Backtracking flattens all rows to a near-horizontal angle during these periods, sacrificing some tracking gain to eliminate shading. The net effect is a small energy loss at dawn/dusk but prevents 5–8% shading-related losses that would otherwise occur.

Q. What maintenance does the drive system require?

Slew drives are sealed, grease-lubricated units requiring inspection every 2 years and grease replenishment as needed. The drive motor is an IP65-rated unit with brushless DC design for long service life. The 5-year drive warranty covers motor, gearbox, and controller electronics.

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