Case Study


Southern Gas Networks


Portsdown Hill


Biomethane Virtual Pipeline




In 2013, PROjEN (formerly Capita PROjEN) were appointed to undertake the detailed design of a new Biomethane injection facility in the South of England. This project was a first in the UK using the concept of a Compressed Natural Gas (CNG) virtual pipeline to enable multiple remote Biomethane sources to be injected into the grid simultaneously.

The Project Scope

The project works included specifying and designing the interfaces between:-

  • Pressure Reduction from 300 barg to 25 barg
  • Fast Gas Analysis
  • FWACV Ultrasonic Metering
  • Trailer Stanchion – all mechanical (pneumatic) and control cabling interfaces between plant and trailer
  • Control System with Executive Actions
  • Air Compression System
  • Site Utilities & Distribution Upgrade.

The Challenge

The use of CNG to transport the gas meant that the pressure exceeded the standard UK gas standards and hence the engineering design of the site required the use of modelling and the application of wider International standards, (especially with regards to the definition of the associated hazardous areas).


A successfully delivered, complex project which was the first of its kind in the UK.

Project Cost



18 months.


Southern Gas Networks


  • Access to a single business with both biogas and natural gas experience was highly desirable but relatively rare in the UK. As PROjEN can boast this combination of skills, the client was able to place a larger element of the scope with a single business thus reducing the number of interfaces/relationships that they had to manage.


Given our wide range of experience in the Bioenergy sector, combined with many years of gas engineering experience, we were the ideal choice and a safe pair of hands for the delivery of this project.