National Grid chooses NEC4 for new £1 billion Project 13 power tunnel

NEC Users’ Group gold member National Grid, which owns the electricity transmission network in England and Wales, has let the first of five NEC4 contracts to procure a second power tunnel in London under a Project 13 enterprise based delivery model.

The £400 million shaft and tunnelling works were let in January 2020 to a Hochtief−Murphy joint venture under an NEC4 Engineering and Construction Contract (ECC) Option C (target contract with activity schedule). At 32.5km in length it is the UK’s longest single tunnel contract.

Four further NEC4 ECC Option C contracts − which all have 14-day payment terms − will be awarded in due course, and there will be a mechanism across all contracts to incentivise cross-contractor collaboration.

Project 13 enterprise

National Grid is one the first adopters of the Project 13 delivery model recently developed by the Institution of Civil Engineers and UK Infrastructure Client Group. It is managing the project as an integrator, using NEC4 ECC Option C to incentivise each contractor based on multiple project outcomes, and the contractors will work collectively as an enterprise to mitigate cost, add value and secure delivery.

Project director Gareth Burden said, ‘The Project 13 model means our stakeholders, customers and suppliers will be at the heart of our programme. Value will not just be defined in terms of the new infrastructure we will deliver, but in the social and economic benefits the project will bring to south London.’

The new transmission cable tunnel and its seven shafts will run 10−63m underground between Wimbledon in the west and Crayford in the east. Measuring up to 4m in diameter, it will replace three existing transmission circuits which currently run under road surfaces. Work started in March 2020 and is due for completion by 2026.