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Project: EGL2 Horizontal Directional Drilling – Peterhead

Key Project Details

Client:

  • NKT

Project: EGL2 (Eastern Green Link 2) Horizontal Directional Drilling

Location: Peterhead

Start date:

  • 12th January 2026

End Date

Duration:

  • 3 months

Contract Value:

  • £1.2m

The Challenge

As part of the Eastern Green Link 2 (EGL2) project—the largest ever project in the UK transmission system—Aaron Engineering Group was required to execute horizontal directional drilling (HDD) operations at Peterhead to install cable ducts under two high-pressure gas mains feeding a local power station. The project presented significant technical challenges including the risk of collision between the drilling head and existing gas pipelines, requiring innovative solutions and precision planning. Two separate circuits needed to be drilled at 190 metres in length with multiple bore holes, each requiring installation of various diameter ducts (280mm, 125mm, and 110mm SDR11 PE100) to accommodate power, earthing, and communications cables. The works demanded close collaboration with Scottish Water and gas line asset holders to ensure full compliance with inspection and hold point requirements whilst maintaining the highest safety standards in a complex, restricted access environment.

What We Did

Aaron Engineering Group was procured by NKT to deliver comprehensive HDD works between January and April 2026. Our scope included:

Pipeline Protection and Safety Innovation:

  • Development and installation of steel protection plates positioned 3 metres lower than the gas pipelines to eliminate collision risk with the guided drilling head
  • GPS-guided drilling rig equipped with guided drill head and copper guide wires to allow continuous tracking and ensure no contact with existing services

Horizontal Directional Drilling Operations:

  • Drilling of 190-metre horizontal bores for two circuits
  • Installation of 6 bores per circuit with 6 ducts per bore (12 ducts total per circuit)
  • 3 no 280mm SDR11 PE100 ducts per circuit
  • 2x 125mm SDR11 PE100 ducts per circuit
  • 1x 110mm SDR11 PE100 duct per circuit

Duct Installation and Quality Assurance:

  • Continuous welding of all ducts prior to installation through bores (200 SDR11 duct welds overall)
  • Installation of welded duct strings through drilled bores
  • Quality verification using duct manufacturer-approved proving mandrel on all installations

Stakeholder Coordination and Compliance:

  • Close collaboration with Scottish Water and gas line asset holders
  • Full compliance with inspection and hold point requirements
  • Robust health and safety management including continuous audits, site inductions, and daily briefings

Sustainability and Site Management:

  • All construction plant complied with Euro 6 emissions standards
  • Paperless site management system implemented to reduce paper use and increase efficiency

Digital reporting, inspections, and record management to reduce waste and improve traceability

The Outcome

  • Two circuits successfully drilled at 190 metres in length with zero collision incidents
  • All required ducts (280mm, 125mm, and 110mm SDR11 PE100) installed and verified through both circuits
  • Approximately 4,000 hours worked with zero accidents achieved
  • 200 SDR11 duct welds executed to maintain continuous pipe integrity throughout the HDD
  • All ducts successfully passed quality testing with manufacturer-approved proving mandrel
  • Full compliance achieved with Scottish Water and gas line asset holder requirements
  • All inspection and hold points completed to stakeholder satisfaction
  • Works delivered to programme and technical specification

Added Value

This project demonstrates Aaron Engineering Group’s capability to deliver complex, technically challenging HDD operations on critical national infrastructure. Through innovative pipeline protection solutions—specifically the steel plate methodology positioned 3 metres below gas mains—combined with GPS-guided drilling technology and continuous tracking systems, our teams eliminated collision risks whilst maintaining drilling precision over 190 metres. The implementation of continuous duct welding prior to installation, verified through manufacturer-approved proving mandrel testing, ensured the integrity and quality of the cable infrastructure. The successful coordination with multiple stakeholders (Scottish Water and gas asset holders), combined with an exemplary safety record across 4,000 hours of work, demonstrates our commitment to delivering complex underground infrastructure projects safely and professionally on programmes of national significance.