Form and function - electricity pylons

Materials World magazine
1 Aug 2011

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.

Further information

IOM3 Materials Information Service

Pylon Design Competition