Meta study of the characteristics of overhead lines and underground cabling
In 2011, Swissgrid commissioned a meta study at the Technical University of Ilmenau with the goal of deepening the level of knowledge about the subject of overhead lines and underground cabling The Technical University of Ilmenau was asked to conduct this meta study because it has proven its considerable expertise in the electronics sector in the German-speaking region and is unbiased towards circumstances which predominate in Switzerland.
Which goal is the meta study pursuing?
This meta study aims to examine and summarise current findings on the topic of «characteristics of overhead lines and underground cabling» by analysing existing fundamental scientific investigations and project studies in Europe. In this way, the meta study will create a scientifically sound basis, one which reflects current knowledge and the project planning of expansion projects, and allows an overview at a factually neutral level.
For the first time in Europe, within this meta study 176 general and project-specific studies as well as non-specific documents from the years 2000 to 2011 addressing the topic of grid expansion in the power-transmission network were compiled and examined; these materials were published in countries with an infrastructure similar to Switzerland’s.
Who collaborated on the study?
The study was conducted by an interdisciplinary team consisting of engineers along with experts in the social sciences. In addition, a study advisory board was appointed by Swissgrid to represent the various interest groups involved in grid expansion projects; these include members of public authorities (SFOE, FOEN, ElCom), relevant associations and environmental experts (the «High voltage under the ground» Association, the Swiss Landscape Protection Foundation, Sigmaplan), the scientific community (the research office for energy grids at the Swiss Federal Institute of Technology (ETH Zurich), Bern University of Applied Sciences, Valais University of Applied Sciences, Avenir Suisse) as well as from this industry sector (ABB, Swisselectric, Swissgrid).
Why did Swissgrid commission this study?
Swissgrid’s ultimate concern is to ensure a secure long-term electricity supply. This requires the expansion and renovation of today’s already overloaded transmission grid. The pumped-storage capacity currently under construction in the Alps as well as the new federal energy strategy can be implemented only by expanding the strategic grid by 2020. As the national grid company, Swissgrid has an overriding interest in finding the best solution which respects the wishes of both the Swiss economy and the country’s population. Consequently, it has no basic prejudice for or against (partial) underground cabling. Its concern is to present the corresponding impacts of both technologies to the affected interest groups in a neutral, understandable and transparent way.
What are the most important findings of the meta study?
The meta study examines topics dealing with technology, construction, operation, economic viability, the general population and the environment. One thing that became clear is that, in the opinion of the advisory council, only a few studies have addressed relevant decision-making criteria. A quarter of the studies considered fewer than 50% of the criteria. The meta study thus confirms a clear need for a standardised, generally binding process and legally reliable reference frameworks (guidelines, criteria) for the socio-economic evaluation of overhead lines and underground cabling. This must be broad-based and transparently communicated.
Swissgrid sees its mission as providing transparent information about the various characteristics of overhead lines and underground cabling. The meta study provides important findings for grid development taking into consideration current energy policy and the grid expansion necessary to meet it.