Dr Nejc Coz

Job: Research Assistant

Employer: Research Centre of the Slovenian Academy of Sciences and Arts

PhD Thesis: Numerical and experimental modelling of tidal range structures with focus on conservation of momentum through hydraulic structures

PhD Supervisors:  Dr Reza Ahmadian and Professor Roger Falconer


With increasing demand for renewable energy sources the potential for marine renewable energy production is attracting much interest in many parts of the world. The exceptional tidal range of the Severn Estuary in the UK presents a major source of renewable energy. In the past decade much research has been undertaken on harvesting this power. There have been a number of proposals for power generation structures, including: the Severn Barrage, Newport and Cardiff lagoons and Swansea Bay Lagoon. The sheer size of these projects will have a large scale impact on the environment. Therefore it is crucial to have an in-depth understanding of the challenges before any of the projects comes to life. One of the primary focus points are the near and far-field effects on the tidal range as the receding intertidal mudflats and marshlands have a direct impact on the estuarine wildlife. Changes in the tidal range can also significantly affect the level of flood protection and efficient power production. Because of a very high nutrient load, any significant change in the flow velocity and concentration of suspended sediments could make the estuary more susceptible to eutrophication.


Nejc is currently based in Slovenia. He is a Research Assistant at the Research Centre of the Slovenian Academy of Sciences and Arts.

Nejc was based at the Hydro-environmental Research Centre (HRC) at Cardiff University for his PhD. He researched the impacts of extracting marine renewable energy, with a particular focus on the Severn Barrage and lagoons in Severn Estuary. In the past decade or so the HRC has done much research in this field and Nejc built on the work done by his predecessors. To assess the environmental impacts of the structures on the estuarine environment he used an open-sourced CFD model, namely Delft3D, which had been developed by Deltares in the Netherlands. The integral part of Nejc’s research focused on the near and far-field effects of structures on the tidal range, flood risk – both up and downstream of these structures – and any changes in water quality.

During his PhD programme Nejc undertook a 3 and a half month research visit to Tsinghua University in Beijing – to find out more about this experience, click here

Before joining the WISE CDT programme, Nejc did his undergraduate degree at the University of Ljubljana in Slovenia. He graduated in Civil Engineering, with a thesis on dam-break flow analysis of four embankment dams in Slovenia, using simplified computer models. In 2010 he spent a summer as an intern at the Slovenian Environment Agency, in the Hydrometry office, where he was involved in testing the measuring equipment and collecting and analysing data from observation stations.


  • 10th International Conference on Sustainable Energy and Environmental Protection, 27-30 June 2017, Bled, Slovenia. Title: High resolution 3D modelling of the Swansea Bay tidal lagoon
  • 37th IAHR World Congress, 13-18 August 2017, Kuala Lumpur, Malaysia. Title: Modelling the impacts of marine renewable energy structures in the Severn Estuary and Bristol Channel, UK

Keywords: Hydraulic structures, Severn Barrage, lagoons, marine renewable energy, tidal power, Delft3D.

Nejc’s Research Poster