Form and function - electricity pylons
Anyone who has studied engineering, design or technology will know that with a truly iconic design the shape or form follows directly from an object’s function or purpose. Think of the elliptical wings of the Supermarine Spitfire, the body work of the Austin Mini or the wrought iron chains of the Clifton suspension bridge. But can the same be said about the ubiquitous high voltage electricity pylon? The subject polarises opinion, from the Pylon Appreciation Society to those who feel all power lines should be buried out of sight.
Perhaps to improve the image and to sway public opinion in favour of the huge network of high voltage lines that will be required to connect a diverse renewable energy generation network, the UK Government Department of Energy and Climate Change and National Grid announced a competition to design new electricity pylons – a design that has not substantially changed since Sir Reginald Blomfield’s 1927 original.
So why do the vast majority of pylons take on the distinctive, latticework structure, and is this form a direct result of their function? Well, there are some requirements that any new design would have to meet. Ease of assembly is key, because lightweight mobile cranes that can access remote areas are used. The pylons need to be strong enough to support the load of the cable yet light enough to withstand high wind loads. They need to cope with lightning strikes and be readily accessible in the event of damage or maintenance. They need to have an easily constructed foundation, with a small footprint, on a wide variety of ground conditions. They need to be easy to adapt to carry different types of cable, at a variety of heights and configurations. Above all, they need to be cost effective in both initial installation and longer term maintenance.
The latticework structure and the galvanised steel angle sections from which Sir Reginald’s design is constructed meet all these functions and give the pylon its classic form. Speaking at the competition launch, Chris Huhne, the UK Energy Secretary, said, ‘I hope the pylon design competition will ignite creative excitement, but also help the wider public understand the scale of the energy challenge ahead’.
I could not agree more with such sentiment, but given that the basic design has been around since the 1920s and has literally stood the test of time, it will take more than creative excitement to come up with a feasible alternative. Key to any new design will be the materials used, so those hoping to follow in Sir Reginald’s footsteps could do worse than acquaint themselves with the Institute’s Materials Information Service, which handles enquiries from individuals and companies seeking the most appropriate materials for their products. Perhaps the answer lies not in new materials but recycled, and with over 400 offshore oil and gas installations to be decommissioned in UK waters over the next 40 years, there would be a certain irony if the steel was recycled into the renewable electricity pylons of the future. The competition is now closed, and National Grid will announce the winner in October.
Materials World Magazine, 01 Aug 2011