Months before any module cracking was reported, the Skyline II fleet suffered a distinct, documented failure: plastic bearing housings slipping and "exploding" across the portfolio. Arctech's corrective action — riveting/screwing the bearing housings on ~444 units — was completed in January–February 2026. The first cracked modules were found on 11 May 2026, roughly three months later. This page reconstructs the full chronology from the mailbox and the Dropbox 9. Warranty Issues record, and assesses whether the retrofit itself could be the root cause of the cracking.
9 Oct 2025
Bearing failures formally reported by iEnergia (2 Falcon + 1 Angol)
444
Bearing housings in Arctech's retrofit scope
≈9 Feb 2026
Retrofit reception (Angol + LS1; Dinamo/Falcon done by 3 Feb)
11 May 2026
First cracked modules found — ~3 months after the retrofit
Two damage waves — keep them distinct
WAVE 1 Oct 2025 – Feb 2026 · Direct breakage from exploding bearing housings
Failed housings physically destroyed adjacent modules. iEnergia, 10 Feb 2026: "Las piezas explotadas provocaron la rotura de una cantidad significativa de módulos… Estos no fueron reemplazados por el contratista." Photos in 9. Warranty Issues\Broken Modules (Trina-Arctech) dated 7 Oct 2025.
WAVE 2 From 11 May 2026 · Recurrent edge-cracking pattern
A different signature: "cracked modules at the short-side edges", mainly rear glass, some with electrical failure/smoking — portfolio-wide, on trackers with "wave-like movement" and documented torsional deflection. Photos dated 12 May 2026, in folders named Cracks in modules, Gap between modules, Deflection by torsion.
The distinction matters for any RCA: Wave 1 is mechanical impact damage from a failed component (undisputed, Arctech's contractor left modules unreplaced). Wave 2 is a stress-pattern failure whose cause is the open question — and it appeared only after the fleet-wide retrofit.
Full chronology — decisions, pushes, and management
- 9 Oct 2025 · Emilio Toledo → Lucas Fernandes Sena + Octavio Caro (Arctech) · "Portfolio Powertree - New Bearing Housings"
iEnergia formally reports the failure pattern and calls it a design/material problem — on day one."Hemos identificado fallas en tres bearing housings: dos en el proyecto Falcon y uno en el proyecto Angol (adjuntamos fotografías)." … "al repetirse en distintos proyectos, consideramos que puede haber un problema de fondo con la calidad del material o el diseño del componente, que a simple vista se muestra frágil para una pieza crítica." … "Hemos debido realizar visitas a terreno no programadas, se han tenido que reemplazar módulos completos, y lo más relevante: se ha detenido la producción en momentos clave."Email, 9 Oct 2025
Note: module replacements due to bearing failures are on record from the very first report — Oct 2025.
- 9 Oct 2025 · Gerardo Castro (Arctech)
"Hoy estuvimos junto a tu colega Fernando Soto en proyecto Falcon evidenciando un Bearing esférico dañado y… ya hemos elevado este asunto con nuestra sede en China."Email, 9 Oct 2025 — Arctech acknowledges same day and escalates to HQ
- 21 Nov 2025 · Emilio Toledo — portfolio inventory
iEnergia quantifies the fleet-wide status:Project Bearings failed Falcon 2 (+2 already repaired) Angol 7 (+2 already repaired) Los Sauces I 1 Los Sauces II 3 Dinamo 0 (battery/motherboard issues instead) - 24 Nov 2025 · Emilio Toledo → Octavio Caro
"el proyecto Angol se encuentra detenido desde hace casi una semana, lo que está generando pérdidas de aproximadamente USD 500 diarios por menor generación."Email, 24 Nov 2025 — economic escalation
- 3 Dec 2025 · Octavio Caro (Arctech)
Arctech tenders and contracts a repair contractor. Scope: 444 bearing houses."nos encontramos en la etapa final de cierre del contrato con la empresa contratista luego del proceso de licitación… iniciar de manera preliminar los trabajos en los 444 bearing houses con problemas en los proyectos Dinamo y Falcon a partir del miércoles 14 de enero."Email, Dec 2025/Jan 2026
- 20 Jan 2026 · Octavio Caro
"Según lo conversado, iniciaremos los trabajos mañana martes."Retrofit execution begins ~21 Jan 2026
- 3 Feb 2026 · Octavio Caro
"los trabajos en los proyectos Dinamo y Falcon ya han finalizado… estaremos en los proyectos Angoles y Los Sauces 1 el día lunes 9 de febrero para realizar la recepción de los trabajos."Email, 3 Feb 2026
- 9–10 Feb 2026 · Emilio Toledo — work reception, objections on record
iEnergia receives the works and formally objects — and this email confirms the fix was riveting:"Las piezas explotadas provocaron la rotura de una cantidad significativa de módulos en el proyecto. Estos no fueron reemplazados por el contratista. Necesitamos confirmación formal de quién asumirá y ejecutará dichos reemplazos." … "Se identificaron 2 piezas adicionales rotas, ambas sin remache en su bearing. Exigimos reparación inmediata y una garantía formal de los trabajos realizados." … "En Falcon se muestra 1 BH reparado, en visita a terreno preliminar existían 2 BH dañados."Email, 10 Feb 2026 — messageId 1770891302205108100
- 10 Feb 2026 · Octavio Caro
"el período de garantía para los componentes estructurales es de 10 años y… no se ve afectada por los trabajos realizados."Email, Feb 2026 — Arctech confirms in writing that the retrofit does not affect the 10-year structural warranty
- ≈ mid-May 2026 · (Owner site visit)
Troncoso, between trackers 1–5 at Los Sauces I, hears slew drives "moving slowly, in jerky, uneven movements"; finds misalignment at tracker 51 and "a clear and worrying sign of torsional deflection" at tracker 56 — recorded in writing 26 May. - 11–12 May 2026 · Daniel Friedman (O&M) — FIRST CRACKED MODULES
"Ayer en la mañana encontramos 2 paneles en falla, humeando y con trizaduras en el reverso. Adjunto video del cuidador. Estamos investigando el problema pero por mientras Hergo, los dueños de los parques, solicitaron termografía para detectar si es un problema generalizado."Email, 12 May 2026 ("ayer" = 11 May) — messageId 1778597724294158400
- 22 May → 28 Jun 2026
The formal escalation to Arctech documented on the Evidence Timeline: request 22 May, preliminary report 26 May, evidence pack 10 Jun, chases, Arctech's "no significant structural abnormalities" on 28 Jun.
The hypothesis: did the retrofit cause the cracking?
Stick-slip / constrained-bearing mechanism (working hypothesis — unproven)
The question: the added rivet/screw fixes the plastic bearing to (or through) its housing. If the fastener restricts the motion the bearing was designed to allow, two things follow:
- Rotational binding → stick-slip. The torque tube binds at constrained bearings; drive torque (the Skyline II is a "synchronous multi-slew drive system with mechanical transmission") builds elastic torsion in the tube until the friction releases suddenly. Each release is a torsional shock propagating along the tube — into the module clamps.
- Axial constraint → thermal buckling. Slide bearings on trackers normally allow the torque tube to expand and contract axially with temperature. A rivet/screw that pins the bearing axially blocks that expansion; the tube relieves the stress by bowing — which would present exactly as the observed "wave-like movement along the tracker" and the "gap between modules" photographed in the warranty folder.
CONSISTENT with the hypothesis
- Sequence: retrofit completed ≈9 Feb 2026 → first edge-cracks 11 May 2026. No Wave-2 cracking is on record before the retrofit.
- Failure signature: cracks at the short-side edges — where torsional/bending stress concentrates at the outer clamps — not random impact damage.
- Field observations post-retrofit: jerky, uneven slew movement; wave-like motion; torsional deflection at tracker 56; module gaps (axial displacement indicator); misalignment vs as-delivered.
- Wave 2 is portfolio-wide on the retrofitted fleet, same configuration everywhere.
- Arctech's own precedent cases (Chile/Trina, Colombia/LONGi) were on Skyline II — recurrence on this product line.
AGAINST / UNKNOWN — must be tested
- ~3-month lag Feb→May needs explaining (candidates: accumulating fatigue cycles; autumn/winter wind loads; larger thermal swings; detection lag — thermography only began May).
- No cross-map yet of cracked-module positions vs retrofitted-bearing positions. If cracks cluster on non-retrofitted trackers, the hypothesis weakens badly.
- LS2 retrofit status unclear — the documented scope was Dinamo/Falcon (444 u) + Angol/LS1 reception; LS2 had 3 failed bearings but its retrofit record hasn't been located.
- Alternative causes uncontrolled: inherent module fragility (dual-glass 2.0 mm on 33 mm frame), purlin/fastener interface (bolt-washer vs rivets — the Owner's own open question), tracker control behaviour, O&M practices.
- Arctech's 28 Jun position: "no significant structural abnormalities" — an interested party's conclusion, but on record.
How to test it — data requests and field work
| # | Action | What it proves / kills |
|---|---|---|
| 1 | Cross-map: overlay (a) Wave-2 cracked-module locations, (b) the 444 retrofitted bearing positions, (c) Wave-1 failed-bearing locations, on the plant layouts (GA DWGs available per plant) | If cracks cluster at/near retrofitted bearings → strong support. If uncorrelated → hypothesis substantially dead. |
| 2 | Physical inspection of a sample of retrofitted housings: does the fastener contact/penetrate the bearing? Can the tube still slide axially? Measure breakaway torque vs an un-retrofitted unit | Direct mechanical confirmation of binding |
| 3 | Request Arctech's retrofit engineering: the method statement, fastener spec, and the engineering approval for the 444-unit campaign — plus TCU/slew-drive motor current logs (their system measures drive load; ours does not) | Their own design docs either allowed for motion or didn't; current logs show binding as elevated/spiky draw |
| 4 | Thermal test: measure module-gap / tube position morning vs midday on retrofitted rows | Axial-constraint confirmation (gaps should breathe; pinned tubes won't) |
| 5 | Video + accelerometer on a jerky tracker during a full tracking day | Captures stick-slip events and shock magnitude |
Motor current on the layout — feasibility
Short answer: not mappable from our current SCADA — but there are three practical routes.
The Skyline II TCUs communicate via LoRa/RS-485 to Arctech's own controller; motor/slew-drive current is not exposed in the plant monitoring we operate for these sites (no tracker motor-current channel exists in the configured datapoints). Slopes concentrating friction on specific bearings is exactly the kind of pattern a current map would reveal, so:
- Ask Arctech for their TCU logs (route 3 above). Their controller measures drive load; this is the reciprocal of the field evidence they demanded from us, and reasonable to request within the ongoing technical review.
- Clamp-meter campaign: measure drive current on a stratified sample of trackers — flat rows vs sloped rows vs retrofitted vs non-retrofitted — during identical tracking movements. One day of field work per plant gives the map.
- Proxy map now, at zero cost: we already hold the topographic DWGs (Arctech engineering package, Nov 2023) and the failure locations (bearing failures, cracked modules, jerky trackers). Overlaying slope zones vs failure density tests the same friction hypothesis without current data — and can be built from existing files as soon as the failure positions are tabulated per tracker.
Management record — what this timeline shows about iEnergia's handling
- Detection to formal report: same-day to days — 9 Oct 2025 report with photos, fleet framing ("problema de fondo"), on the first recurrence.
- Economic escalation with numbers — 24 Nov 2025, USD 500/day, plant stopped a week.
- Forced a fleet-scale correction — Arctech tendered a contractor and executed a 444-unit campaign within ~3 months of the first report.
- Rigorous reception — 9–10 Feb 2026: refused to accept silently; put on record the unreplaced broken modules, the two un-riveted failed pieces, the Falcon count discrepancy; demanded a formal workmanship guarantee.
- Secured the warranty position in writing — Arctech's 10 Feb confirmation that the 10-year structural warranty is unaffected by the retrofit.
- Escalated the second failure wave within days — cracked modules found 11 May; thermography mobilised 12–13 May; formal manufacturer escalation 22 May; written portfolio report 26 May.
This page is a technical/management record. Its hypothesis is deliberately excluded from the legal correspondence until tested — an untested causation theory cuts both ways.