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Unlocking Low-Carbon Megawatts and Megabytes: Why Construction Access Determines Deliverability for Solar Farms and Data Centres – Part 2

Across the UK and Ireland, solar farms and data centres are scaling at unprecedented speed. But an issue that rarely gets the attention it deserves is now becoming one of the biggest threats to deliverability - can critical loads even reach the site? In part 2 of this four-part series, we discuss the critical path nobody talks about: construction route and access.

10^th December 2025

Unlocking Low-Carbon Megawatts and Megabytes: Why Construction Access Determines Deliverability for Solar Farms and Data Centres – Part 2

The Critical Path Nobody Talks About: Construction Route and Access

In large infrastructure projects, the critical path is typically associated with grid connections, procurement, or civil and electrical works. Yet, for solar farms and data centres, one of the most decisive, and often overlooked, determinants of deliverability are the construction routes and access. These are not secondary engineering considerations; they are fundamental to whether abnormal indivisible loads (AILs), plant, and materials can safely and legally reach a site.

When access is left too late, projects stall not due to technology or financing, but because the road network, structures, or regulatory requirements simply do not permit the movements required. Route feasibility is therefore not an operational detail; it is a front-end risk that belongs on the critical path.

Why Route and Access Matters

Modern solar and digital infrastructure projects are logistics intensive. Solar farms require hundreds of module deliveries, inverters, frames, and transformers transported along rural roads never designed for sustained HGV activity. Data centres depend on heavy prefabricated units, chillers, generators, and large grid transformers that require STGO movements through constrained urban environments.

If the route is not viable, or if consents and notifications are not secured, construction programmes halt. Delays of weeks or months are common when route feasibility is assessed only after planning. Early clarity on access is therefore a strategic risk-management tool, not a technical nicety.

Illustrative Vehicle Types and Why They Matter

Construction access challenges are often rooted in the physical scale and behaviour of the vehicles involved. Typical construction deliveries use rigid HGVs or articulated lorries, whereas key components for solar farms and data centres often require Special Types General Order (STGO) abnormal load vehicles. Typical vehicles can include:-

Standard Construction HGVs – 12–18 tonne rigids or 16.5m artics delivering modules, frames, fencing and general materials.
AIL / STGO Vehicles – Multi-axle low-loaders (CAT 1–3), 30–48m in length when carrying transformers, switchgear or prefabricated electrical units.

These vehicles have vastly different turning radii, swept envelopes and width requirements. A junction that accommodates a standard artic may be entirely impassable for a transformer convoy. This is why geometric constraints rapidly become project critical.

Typical Profiles: Solar Farms vs Data Centres

Understanding the physical context is key:

Solar Farms

Predominantly rural locations with narrow, weak, or single-track roads
Agricultural bridges and culverts with unknown or low load capacities
Seasonal constraints (flooding, thaw, harvest periods)
Limited opportunities for temporary widening without environmental impact

Data Centres

Proximity to urban centres and high-voltage infrastructure
Tight junctions, roundabouts, low-clearance structures, and street furniture
High community sensitivity to HGV movements
Construction and operational traffic both significant

Despite these differences, both sectors rely on road networks never designed to accommodate the size, frequency, or weight of construction traffic required.

Common Choke Points

Across a wide range of UK and Irish projects, several recurrent obstacles consistently undermine access planning:

Third-Party Land

Optimal AIL routes often require temporary land take for manoeuvring or local widening
Negotiations can take months and may conflict with agricultural seasons
Refusals can force significant rerouting or engineering solutions

Urban Sections

Tight bends, multi-arm junctions, and bus/cycle priority layouts can restrict STGO movements
Works may require night-time deliveries, phased traffic management, or partial disassembly of street furniture
Local authority approvals introduce additional lead time

Weak or Unknown Structures

Many rural bridges and culverts were never assessed for modern STGO loads
Load assessments, strengthening works, or complete avoidance may be required
Utilities often run within or alongside structures, adding complexity

Narrow Rural Links

Single-track roads cannot accommodate long trailers or meet-passing movements
Temporary widening may trigger ecological surveys, planning applications, or land agreements
Restricted visibility and bend geometry may eliminate routes entirely

Statutory Undertaker Constraints

Overhead lines, ducts, chambers, gas crossings, and telecoms infrastructure can obstruct trailers
Diversions carry long lead times and unpredictable costs
Coordination across multiple undertakers magnifies risk

These choke points are not theoretical; they recur across the majority of grid-connected renewable and digital infrastructure projects.

The Hidden Cost of Late Action

Deferring route and access feasibility is a false economy. The consequences include:-

Programme Slippage: AIL movements are often on the critical path, delays cascade into energisation dates
Cost Escalation: Unplanned bridge strengthening, widening, or statutory undertaker diversions
Planning Risk: Authorities may impose restrictive conditions or request further assessment.
Community and Reputational Impact: Poorly managed traffic movements generate resistance.

Ignoring access risk undermines not only construction timelines but also the credibility of the project.

Why Early Feasibility Matters

Proactive planning transforms access from a bottleneck to an enabler through:-

Integrate route feasibility into site selection
Carry out early swept-path, structure, and geometry assessments
Engage highways authorities and police early (particularly for STGO movements)
Identify statutory undertaker constraints through early desktop utility reviews
Budget and programme for route upgrades or temporary works

Early feasibility provides the certainty developers need to protect both programme and cost.

Key Takeaway

Construction route and access is not a minor detail; it is a critical path activity that can make or break project delivery. As solar farms and data centres scale up, developers must shift from reactive fixes to proactive strategies.

Next in the Series – the solutions and tools that de-risk construction access

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