The first (non-power generating) proposal for a Severn Barrier was developed by Thomas Fulljames in 1849
This story is part of our series - can the UK go 100% renewable and was originally posted at Greenwise business.
As debate around the latest incarnation of the controversial Severn Barrage scheme rumbles on, an alternative vision for renewable energy in the Bristol Channel promises comparable amounts of power, less environmental damage and better long-term economic prospects. So is it time for a rethink?
It is nearly a century since the first proposal to build a barrage across the Severn to generate power from the tides. Since then we have developed our National Grid, embarked on a dash-for-gas and built a fleet of nuclear power stations. Yet, still there is no Severn Barrage.
And now the fate of the latest proposal – led by private consortia Hafren Power – hangs in the balance. As an influential body of cross-party MPs prepares its conclusions to a review it held earlier this year, the consortia’s chief executive warned that a negative outcome could effectively kill the project.
The latest proposal. Source:
Hafren Power (2013)
A new vision
In timely fashion then, a coalition of organisations led by RegenSW has developed a new ‘balanced technology’ vision that challenges a narrow focus on a single ‘mega project’. Instead, it considers the whole of the Bristol Channel area from the Severn Estuary to the Atlantic, and presents a scenario where a mix of complementary marine renewable technologies are incrementally deployed to exploit the full range of energy resources on offer.
The area would be a test bed for early-stage technologies such as wave power devices and tidal stream generators (essentially underwater wind turbines), which could start small and scale up as concepts are proven and costs come down. At the same time, established technologies such as offshore wind and, yes, even smaller tidal barrages, could be built at commercial scale from the word go.
Resource areas for wind, wave
& tidal energy in the Bristol Channel. Source: RegenSW (2012) A Balanced Technology Approach.
Comparable energy potential
Proponents of the £25 billion Barrage say it is the only way to fully harness the tidal resource of the Severn. But analysis undertaken as part of the RegenSW vision shows that between 10-15 gigawatts of renewable power could be harnessed across the area, with or without a large barrage.
One reason for this is that a large barrage, such as that proposed by Hafren, would render tidal stream generators infeasible across much of the Bristol Channel, whereas the RegenSW would allow a multitude of generators to flourish.
Environmental benefits
According to Hafren, its latest barrage proposal will utilise new technologies to reduce damage to wildlife compared to previous schemes. However, evidence given to MPs puts these claims into perspective; new “fish-friendly” turbines are not yet proven, and a quarter of the intertidal zone so crucial to birdlife would still be lost.
In contrast, the incremental deployment of smaller projects would allow technologies to be tested and their impacts on wildlife understood before scaling up. In this scenario any tidal barriers would be much smaller in scale and placed along coastal bays and inlets, meaning less habitat loss.
Economic benefits
A further claim is that the Hafren barrage would create 50,000 net jobs, a figure one MP involved in the recent review described as “not credible”. Bristol Port Company remains far from convinced that the new barrage design would not negatively impact on its activities – the main reason a 2010 Government report identified a net gain of only 120 jobs.
The longer-lasting economic impacts of a barrage would also be limited once construction is complete; as a global one-off it is unlikely to lead to an exportable local industry. In contrast, the region is already home to a number of wave and tidal stream firms. Used as an international showcase for these technologies, the Bristol Channel could create a base in the region from which to export around the world for decades to come.
A prototype tidal stream
turbine, built by Marine Current Turbines based in Bristol
More deliverable
For all the charm of a mega-project capable of supplying five per cent of the UK’s electricity, Severn Barrage proposals have always been heavily contested. The scale of the project is matched by the scale of opposition and complexity of approval processes. Hafren’s plans to reach financial close in 2015 and full operation by 2025 seem at best optimistic, and at worst a fantasy.
On the other hand, smaller, less controversial projects would be deliverable sooner and mean Bristol Channel renewable power feeding the grid well before 2025.
Incompatible approaches?
It’s true that elements of the balanced technology approach could still support a large barrage. But there are real conflicts and opportunity costs too.
For example, subsidy for low carbon power is capped under the Levy Control Framework. Directing a large portion of this to a single piece of infrastructure would inevitably mean less support elsewhere, and could also mean less bank for our buck too. Peter Hain MP estimates the barrage could need a level of subsidy comparable to offshore wind, whereas analysis from the Carbon Trust suggests tidal stream generators have the potential be cheaper than this by the mid 2020s.
And for as long as attention is focussed on a single controversial mega project, uncertainty reigns, a hiatus is created, and investment in alternative technologies held back.
The new vision for renewable energy in the Bristol Channel is both inspiring and practical. But the latest proposal for the Severn Barrage is simply getting in the way.
This article was originally posted at Greenwise business.
