Next Generation Overhead Lines with Carbon Core Conductors: Optimisation of Design Paradigm to meet the Needs of Energy Transition and reduced environmental Footprints

While CCCs are mainly used for reconductoring, their potential for new overhead line (OHL) projects - particularly in environmentally sensitive or challenging terrains - remains underexplored. This paper examines the potential of CCC in construction of new overhead lines.

CCCs offer key material advantages, including a low coefficient of thermal expansion (CTE), high tensile strength, and lower weight compared to traditional steel-core conductors. These properties enable longer spans, fewer towers and lower sag, which can significantly reduce environmental impact during construction and operation. By using CCCs, projects could minimise infrastructure footprints, lower CO₂ emissions, and reduce line (I2R) losses over the asset’s lifespan (TCO). However, this paper mainly focuses on environmental benefits. Greenhouse gas emissions are analysed, including topological considerations such as mountainous areas (e.g., 700 meters above sea level) which present challenges due to uneven terrain and limited access, requiring specialized equipment. In flat terrain (such as around Vienna) the logistics are simpler, with dirt roads and steel plates used for stability. For a 100 km 380 kV OHL, diesel consumption reaches 2.024 million litres (vehicles plus helicopter use), resulting in 4,918 tons of CO₂e emissions during construction. Manufacturing emissions for 300 towers (distinction is made between suspension and tension towers) add 35,300 tons of CO₂e, primarily from steel production and concrete foundations. Conductor manufacturing emissions are excluded, as they are similar for both ACSR and CCC conductors1.

The paper evaluates three scenarios for span length increases over nominal 330 m (to 352 m

(=+6.67%), 369 m (=+11.82%) and 386 m (=+16.97%) under varying tensions) using the newly designed CCC Graz conductor, demonstrating CO₂e savings of 5.09% to 12.57% compared to standard ACSR conductors. Fewer towers yield lower steel and concrete consumption, saving up to 5,057 tonnes CO2e emissions for a given 100 km line.

Project costs of such a line can be higher than conventional OHL but depending on the valuation of the increased environmental performance and other considerations, new lines with

CCC can offer an overall advantage.