Climate Change – What Do We Know, What Do We Not Know, and What May Be the Consequences For Electric Overhead Line Systems?

The validity of global climate beinginfluenced by emissions of CO2 and other greenhouse gasesfrom human activities is now globally recognized. Althoughthe global temperature is expected to rise, and consequentlyalso precipitation amounts, many secondary effects are stilluncertain, concerning for example flooding, stormfrequencies, atmospheric icing and so on. However, manyelectrical utilities around the world are already consideringpreventive measures for their network, based on thephilosophy that proactive measures in the long run arecheaper than taking extra costs for maintenance and repairafter expected increases in damage and outage frequencies

Assessing environmental actions from modern meteorology

This paper gives an overview of current achievements where modern weather forecasting techniques are implemented for the assessment of especially ice and wind loadings on electrical overhead lines, TV towers, masts and similar infrastructure. Modern numerical weather prediction models (NWP ) incorporate far more details on e.g. cloud physics and dynamics than those generally necessary for regular weather forecasts. Such models describe in principle all physical and dynamical processes in the atmosphere in 3-D. In combination with detailed data on the physical properties of land and water surfaces, it is now possible to obtain realistic values of weather parameters related to wind, turbulence, precipitation and atmospheric icing down to a horizontal scale of a few hundred meters. Such models are therefore powerful tools for the planning and final design for various infrastructures in remote terrain where little or no weather data can provide sufficient bases for the establishment of extreme weather loads necessary for their design

Summary of the Meeting on 11 December 2015 on Adaptation of Structural Design to Climate Change

The objectives of the meeting were as follows: 1. Discuss the feasibility and needs for creating snow map for structural design which accounts for the climate change: • availability of methodology and data; • scope of a snow map project – geographic, time span; • support / resources needed. 2. Set-up a group to create a document on the rational and needs for a snow map for structural design which accounts for the climate change. 3. Discuss the interaction with CEN/TC 250 Project Team (PT) on SC1.T5 (the Project Team on the CEN report on adaptation of the Eurocodes to the climate change, Task 5 of SC1, under Mandate M/515). 4. Identify other actions on structures whose effect on structures shall be consideredJRC.G.4-European laboratory for structural assessmen

Summary of the meeting on 11 December 2015 on adaptation of structural design to climate change - Support to the implementation, harmonization and further development of the Eurocodes

It is expected that the global warming will reduce the frequency of the snow events. On the other hand, the intensity of extreme snow events may increase, since the capacity of the atmosphere to hold moisture increases with temperature. This may lead to the increase of both snow density and occurrence of extreme snowfalls in regions where temperatures still may happen to be below freezing level during precipitation events. To assess the evolution of the snow load and its impact on design of new buildings and on reliability of existing ones, a comparison of future trends, in both intensity and frequency of future precipitation in cold areas with current versions of snow load maps for structural design should be performed. The European Snow Loads Research Project was carried out under contracts with the European Commission DG III – D3 in the period 1996-1999 with the aim to provide scientific basis for harmonized definition of models for determining the actions of snow applied to the structural parts of construction works. The project was led by Pisa University. The snow load design map produced by this project is incorporated in Annex C of EN 1991-1-3 with the aim to help National Competent Authorities to redraft their national snow maps and to establish harmonized procedures to produce such maps. A pilot study on creating a snow load map for structural design taking into account the climate change was launched at a working meeting on 8 April 2014 at JRC/Ispra with the participation of Pisa University and the JRC CRM and ELSA Units. While the study has been performed in Pisa University, the JRC CRM Unit provided data on climate change projections, and the two JRC Units consulted the approach and the results. The results obtained show that the developed procedure is very appropriate for the creation of snow maps taking into account the climate change implications, since it allows to estimate characteristic ground snow loads on the basis of daily data Tmax, Tmin and h rain, which are typically available as outputs of climate change projections for all possible scenarios

Systems for prediction and monitoring of ice shedding, anti-icing and de-icing for power line conductors and ground wires

This TB presents some operational or potential anti- and deicing systems (AI/DI). However, for a better understanding and appropriate application of the recommended techniques, the TB also informs on some fundamental aspects of ice accretion and its mechanical and thermodynamic behaviour. The promising potential of new materials such as AI coatings and the role of modern meteorological forecasting models for reliable use of AI/DI techniques are also discussed