The issue of grid aesthetics is really a question of image. For example, the concept of ‘industrial soldiers marching across the landscape’ was used to support an entry in a 2008 competition for a new pylon to be used by Italian TSO Terna.
This edited contribution by internationally renowned architect, Hugh Dutton of Hugh Dutton Associés (HDA) in Paris, argued that the core issue today goes beyond the aesthetics of any single pylon design. Rather it is now mainly a question of the image and identity of the entire power line.
It is useful to reflect on the fact that trellis (lattice) type pylons were once considered a symbol of progress and by that definition enjoyed a mostly positive image. A decades old electoral poster for then Presidential candidate, Francois Mitterand, for example, portrayed him alongside a trellis pylon. Today, by contrast, political candidates usually promise ecology and green fields. Times have changed and the image of power transmission must change as well. It must also adapt to new technologies as well as a society with a much different state of mind. Development of power lines must further respond to new communication possibilities when it comes to public forums and discussion.
Some major power companies, such as Terna, RTE and National Grid, have taken the initiative to hold design competitions on aesthetic designs for their new transmission systems. Indeed taking the step of considering and debating aesthetic design for overhead lines is fast becoming a necessity. Acceptance of new power lines in the communities and places affected can be considerably improved if the public can share and participate in the debate and consideration of alternative proposals.
For example, the Equilibre design for the Avelin-Gavrelle Line in northern France was selected in the final stages by a committee of local representative groups. The process of acceptance of the line is followed through an active blog that RTE maintained on line, encouraging interaction with the community and providing periodic updates and information: http://www.rte-ligne-avelingavrelle.com. Indeed, this internet forum is an essential ingredient in the communication of design and a whole new image for electricity transmission.
Nature as Inspiration
HDA normally designs structures, buildings, facades, bridges, etc. and came across designing power pylons when invited to participate in a competition by Terna in Italy. This allowed approaching the topic with a ‘fresh mind’. Creativity is essential to good design and work is often inspired by nature, which provides the ‘rules to play by’ and also offers solutions to inspire. For example, trees do a similar job to the one being asked of power pylons yet accomplish it with natural elegance and poise.
Much of the work at HDA has involved tensile structures based on early work in cable-stayed facades. In fact, a cable-suspended footbridge in Turin inspired the firm being invited to participate in the Terna competition. Using tension structure concepts to resolve design of high-tension (voltage) lines was therefore an immediate consideration. The idea was based on the belief that the silhouette of power line structures could be better controlled if certain of their components were considered in tension. These could disappear, or at least diminish in visual impact, when viewed from a distance, leaving a freer hand to design the silhouette. This approach led to the design of Germoglio for Terna.
Understanding the non-linear nature of tensile structures led to an entirely different approach than found in traditional ‘suspension’ and ‘tension’ pylon typologies. Rather than considering only occasional pylons as capable of resolving tension forces on conductors, it was proposed that all pylons be capable of sharing the tensile forces.
This unconventional approach encountered difficulty being accepted in an industry that has always considered dual roles of pylons that generally follow a zig-zag route, since change in angle normally occurs at tension pylons. Suspension pylons, by contrast, generally follow a straight line. If all pylons are designed to resolve tension and to change angle, this allows designing a more fluid path across the landscape.
This is desirable if the goal is for a line to respond well to topography or transport corridors that are usually curvilinear. Both Terna’s Germoglio and RTE’s Equilibre use concepts of ‘tensegrity’ and ‘load sharing’ in design of both lines and pylons.
Wind turbines should probably be considered in any reflections on the changing image of power transmission. These are beautifully designed and are part of what the public sees as a noble cause. However, like the first trellis pylons that began as symbols of a bright future, they too are becoming commonplace and are even finding opposition because some see them as anonymous and invasive. Power line design should ideally have some element of territoriality and this way become a symbol of a specific place. Indeed, if lines can become an identifiable part of a particular community or landscape – something different for others regions – people around them can begin to take pride in them. That would be a huge step forward.