An energy and carbon life cycle assessment of tidal power case study: The proposed Cardiff–Weston severn barrage scheme

Under the Kyoto Protocol many countries have targets to reduce carbon emissions and increase renewable energy production. In order to do this effectively the impact and efficacy of differing schemes must be determined. One option for producing electricity is through the use of a tidal barrage. The largest potential barrage scheme considered in the UK is the Cardiff–Weston barrage scheme in the Severn estuary. The scheme would be a single, renewable installation and is predicted to constitute 4% of the UK electricity supply. Therefore a carbon and energy assessment was completed on the Cardiff–Weston Severn barrage scheme. The assessment shows that the energy and carbon intensity of the Severn barrage is small in comparison to the National Grid mix and that, given reasonable assumptions, the Severn barrage can contribute to meeting the UK carbon reduction target. Importantly, the operation stage was identified as both the most energy and carbon intense by a large margin. This is a notable finding as preceding studies have tended to dismiss the consequences of the barrage operation as minimal or nil. Whilst these findings are for the Cardiff–Weston barrage, the implications will be similar for tidal barrages in other sites in the UK and globally.

► Presents a case study life cycle inventory of the Cardiff–Weston tidal power scheme.
► Quantitative estimates are made for the carbon emissions and the energy demand.
► ‘Operation’ has the highest contribution to total impact due to electricity demand.
► Impact of UK National Grid is shown to be a dominant variable to scheme impact.
► Exemplar of the importance of thorough analysis of all life stages of power schemes.