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

Abstract

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.

Life Cycle Assessment of Electricity Generation from an Array of Subsea Tidal Kite Prototypes

“…This study was not part of the literature review due to the aggregation of data of different tidal turbines into main categories, but used later in the discussion of the results (Section 3.3). Amponsah, et al [37] and Walker and Howell [38] performed comparisons of different technologies, but were excluded, as they used results directly from other LCA studies [11,39] which are included in our review. Other studies had the LCA performed on the same technologies, but with varying scopes and different results; thus, they were included in the table (SeaGen in [40] and [11]; Severn barrage in [39] and [41]).…”

“…Rule, Worth, and Boyle [43] and Douglas, Harrison, and Chick [11] only state recycling rates for different materials without describing the modelling aspect, although from the graphs it can be seen as negative flows (credit). Kelly, McManus, and Hammond [39] and Woollcombe-Adams, Watson, and Shaw [41] go further and exclude the EOL stage, stating that its impact is negligible.…”

Current tidal power technologies and their suitability for applications in coastal and marine areas

“…A particular advantage of tidal range structures is their very long lifespans; for example, the design lifetime of the proposed Severn Barrage is 120 years, with turbine replacement occurring every 40 years (Kelly et al 2012). Range structures have such long operational lifetimes due to the fact that the turbines are enclosed within a sturdy concrete structure and are consequently less exposed to the marine environment, with relatively easy access provided for maintenance work.…”

Global Sustainability Accounting—Developing EXIOBASE for Multi-Regional Footprint Analysis

“…Similarly, the high technological costs of current state ocean-based technologies as of 2007 show relatively higher impacts (particularly employment at this stage of development). However, earlier life-cycle studies that focus on the longer term potential of the technology indicate greenhouse gas emissions could become lower than the average UK power mix generation [78] or electricity from wind turbines [79]. Employment 1000 p.…”