Case Study

EGL2 Power Line
Weather Risk Intelligence

Client: BAM Nuttall / SSE Energy Networks Location: Beauly to Denny, Scotland Sector: Energy / Transmission

How WeatherWise helped BAM Nuttall and SSE Energy Networks manage weather risk across a 120km overhead power line through the Scottish Highlands.

Project Overview

The EGL2 (Eastern HVDC Link 2) project involved constructing a 120km high-voltage overhead power line from Beauly to Denny in Scotland. This major transmission infrastructure project, delivered by BAM Nuttall in partnership with SSE Energy Networks, traversed some of the most exposed terrain in the Scottish Highlands.

The route crossed multiple mountain passes, river valleys, and areas of elevated terrain where weather conditions vary significantly over short distances. With hundreds of tower locations and years of construction activity, managing weather risk was critical to programme delivery and cost control.

The Challenge

Constructing a 120km transmission line through the Scottish Highlands presented extreme weather challenges that threatened the programme at every stage.

Extreme Weather Exposure

The route traverses multiple mountain passes where wind speeds frequently exceed crane operational limits. Conditions at elevation can be dramatically worse than valley-floor weather stations suggest.

Multi-Year Programme

A construction programme spanning multiple years across diverse terrain sections, each with different weather sensitivities and seasonal constraints affecting tower erection and stringing operations.

Wind-Critical Crane Operations

Tower erection requires heavy crane lifts at height, where even moderate wind speeds force operations to stop. Predicting safe lifting windows was essential to avoid costly standby time.

Seasonal Working Constraints

Working at elevation during Scottish winters is severely limited by snow, ice, wind, and reduced daylight. Accurate understanding of seasonal weather windows was essential for realistic programme planning.

The Solution

WeatherWise provided a comprehensive weather risk intelligence platform tailored to the unique demands of the EGL2 transmission line project.

1

Site-Specific Weather Calendars

Individual weather calendars for each section of the route, accounting for differences in elevation, exposure, and terrain across the 120km corridor.

2

Probabilistic Crane Forecasting

Wind speed forecasts calibrated to crane operational thresholds, identifying safe lifting windows days in advance for each tower location.

3

Weather Risk Quantification

Probabilistic analysis of weather-related time risk for the programme, enabling accurate contingency planning and resource allocation.

4

Claims Evidence Trail

Automated weather recording from day one, building the contemporaneous evidence trail required for weather delay claims under the NEC framework.

Results

Measurable improvements in weather risk management across the EGL2 programme.

±5%

Contingency Accuracy

Improved from ±30% to ±5% weather contingency accuracy

Lower

Standby Costs

Reduced weather standby costs through better window planning

Higher

Crane Utilisation

Better crane utilisation through weather window planning

Robust

Claims Evidence

Contractual evidence for weather delay claims under NEC

Key Takeaways

  • 1

    Site-specific data beats regional averages. Weather conditions at elevated tower locations differed dramatically from nearby weather stations. Accurate, location-specific data was essential for realistic planning.

  • 2

    Weather calendars per programme section. A single weather assumption for a 120km route would be dangerously inaccurate. Sectional weather calendars reflected the true variability of conditions across the Highland terrain.

  • 3

    Evidence trail essential for claims under NEC framework. Starting weather recording from day one built the contemporaneous evidence trail needed to substantiate weather delay claims throughout the programme.

Frequently Asked Questions

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How does WeatherWise help with crane lift planning?▾
WeatherWise provides probabilistic wind speed forecasts calibrated to crane operational thresholds at each tower location. This allows teams to identify safe lifting windows days in advance, reducing costly standby time and improving crane utilisation across the programme.
What are weather calendars?▾
Weather calendars are site-specific models that predict the probability of working days being lost to weather for each activity type. On transmission line projects, separate calendars can be created for each section of the route, accounting for differences in elevation, exposure, and terrain.
Can WeatherWise provide evidence for NEC weather claims?▾
Yes. WeatherWise automatically records weather conditions at your site coordinates from day one, establishing the contemporaneous evidence trail required for NEC compensation events. The system generates reports comparing actual conditions against the 1-in-10 year baseline.
Why is site-specific data important for Highland projects?▾
The Scottish Highlands have highly variable microclimates. Regional weather stations can be tens of kilometres away and at different elevations. Site-specific data provides accurate conditions at each tower location, which can differ dramatically from the nearest weather station.

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