Utility Week

UTILITY WEEK | AUGUST 2022 | 41 third of the tunnels completed and cables on order from a company in South Korea, the project will "very quickly" become a t out and cable installation project in November and December, according to Burden. Leading the tunnel boring charge thus far has been what Burden describes as a "world rst" automated ring build. He explains that the project's standard tunnelling process sees six 800kg segments laid in a ring at the back of a boring machine before the machine is "shoved" forward through the most recent ring and repeats the process. "Typically there's a miner on a control that moves the segment in and out, but any sort of issue you have out the front is unforgiving," he explains. "We're about to enter phase four of a trial to automate that process rather than having someone on the ring erector on the controls with various bells, whistles, cameras and sensors – you'll basically push a button and it will construct a ring sequence. "We do our best to keep people away from those sorts of hazardous areas," Bur- den continues. "There's never going to be a time where there's nobody at the front of that machine, but if you can move them fur- ther away from hazards like 800kg segments rotating then we should do that." Collaboration commitment Underpinning the project has been National Grid's commitment to Project 13 – an industry-led movement to unite owners, partners, advisers and suppliers to work and innovate in more integrated arrangements, underpinned by long-term relationships, and rewarding an enterprise based on value added to overall outcomes. "It's an initiative from the Infrastructure Client Group trying to look at how we do infrastructure slightly di' erently," Burden says. "We've got ve big contracts that have collaboration clauses, for example." In keeping with this, on top of a claimed "world rst", Burden explains that National Grid has partnered with social enterprise Connectr to engage the next generation of engineers by sending site footage, videos and engineers into south London's schools. The partnership will prioritise STEM (science, technology, engineering and mathematics) and career-based upskilling opportunities for the most disadvantaged schools, colleges and young people across the seven south London boroughs impacted by the construction project. "We said we'd have 100,000 contact points and we're on for about 25 to 30,000 by the end of the school year," he says. "Careers education is probably one of the rst things that fell away in the pandemic." What's more, in an e' ort to trim the pro- ject's sizeable environmental footprint, Bur- den explains that National Grid is diverting 95% of project waste away from land ll, and has deployed cement-free concrete on tem- porary works among a number of measures to cut carbon. "It's a more expensive prod- uct, but nonetheless one that needs back- ing," he says. "Ultimately, if you have a problem on a permanent build – tunnel segments below ground, for example – that's a big risk and designers are rightly going to be very cau- tious because you could end up with a col- lapse. But as far as laying concrete down for a › at surface on which you can then do work safely, it's use shouldn't be an issue. "Then we've done things in the perma- nent works to reduce design footprints and reduce the amount of concrete wherever we can, because ultimately if you save carbon, you save pounds – particularly with the fuel prices doing what they're doing. We are incentivised to do that." Stuart Stone, editor, Utility Week Innovate "We've done things in the permanent works to reduce design footprints and reduce the amount of concrete wherever we can. Ultimately, if you save carbon, you save pounds." Gareth Burden, project director, National Grid "We've done things in the permanent works to reduce design footprints and reduce the amount of concrete wherever we can. Ultimately, if you save carbon, you save pounds." Gareth Burden, project director, National Grid A total of four tunnel boring machines have been employed in digging the 32.5km Power Tunnels tunnels under south london

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