Guest blog – Time for tidal power by Sian John



Sian John is Tidal Lagoon Power’s (TLP’s) Environment Director and Royal HaskoningDHV’s Director of Environment in the UK. A strong advocate of marine conservation and sustainable development, Sian is currently leading the implementation of TLP’s visionary Ecosystem Enhancement Programme. Hailing originally from NZ, she loves the sea.  As a regular contributor to Coastal Futures, Sian is a strong advocate of the appropriate application of the wonderful piece of legislation that is the Habitats Directive.



I have been involved in the assessment of the impact of major infrastructure projects in coastal and marine ecosystems for many years. This has included translating predicted geomorphological effects into ecological impacts and developing appropriate mitigation, compensation and monitoring strategies. The industry has seen significant change in this time, with new forms of development in the marine environment and expanding environmental regulation, and most of this change has been positive. Understanding and responding to the evolving policy landscape and expanding stakeholder expectations, has brought many of us around the table to find solutions that work across the board. Nevertheless, cultural divides have existed that have led to developers and the conservation lobby taking very different positions. The question still has to asked – has blue growth occurred at any cost? Whilst that is debatable, it is clear that the future can’t look like this.

Whilst many aspects of the future are unclear and fear is palatable, from an energy perspective what we do know is that there is an urgent need for low carbon energy generation at scale. The UK’s energy mix has to change, with a number of fossil fuel and nuclear power plant reaching the end of their lives and the new nuclear programme not running at the pace previously anticipated. A progressive energy transition has to be a Government priority. Juxtaposed with this, the UK has the best tidal range resource in Europe and the second best in the world. These tides can be harnessed to generate clean electricity. Tidal barrage schemes in the UK have historically faltered due to serious concerns over their environmental impact, leaving tidal lagoons as the primary option for harnessing this unique resource. Significantly Tidal Lagoon Swansea Bay, at 320 MW, provides a low impact scalable blueprint for lagoons. And TLP’s ambition is to develop, construct and operate a fleet of tidal lagoons that can meet up to 8% of UK electricity demand.

Reducing carbon emissions is only one part of the tidal lagoon story. Future resilience and climate adaptation needs to be built into infrastructure now. Coastal communities and industries are facing the direct effects of climate change, including sea-level rise and more frequent and intense rainfall events, leading to ‘coastal squeeze’ and enhanced flooding. The Severn Estuary Flood Risk Management Strategy [], for example, estimates that by 2025 an additional 497ha of intertidal habitat will have been lost in the Severn. The changing coastline and shifts in the distribution and migration routes of wetland birds means that it is time to think differently about nature and how we approach the management and conservation of natural resources (including energy resources). We need to think about the wider ecosystem, connectivity between habitats and species, and the intrinsic values they hold.

I fully recognise and appreciate the challenge associated with seeking to develop in areas such as the Severn Estuary that are of high conservation importance. Like other forms of development in coastal and marine areas, large-scale tidal energy generation will need to meet UK and current EU environmental obligations. However, TLP is adopting a very different starting position for approaching this. Its vision is to enhance biodiversity alongside the generation of clean energy by 2030 through a targeted nature conservation programme; that is, to be net positive. TLP’s ‘Ecosystems Enhancement Programme’ (EEP) will run alongside lagoon development to demonstrate that zero carbon energy schemes can provide large scale power and invest in the local economy and the natural environment. It is TLP’s belief that this is what every developer should strive to achieve.

As with any approach that seeks to take be different, the EEP is generating much interest.  Feedback on the strategy has included: Do we understand and have we quantified our compensation requirements? Where and how will compensation be delivered? How will you fund this? How will you demonstrate net positive? Are you aware of the full extent of the environmental challenge? In short, yes we are. Our recently launched EEP Strategy sets out how we are proposing to do this:

The Ecosystem Enhancement Programme has three core aims:

  1. To have a net positive effect on biodiversity (that is, to go beyond the achievement of a neutral outcome alone).
  2. To address the compensation and ecosystem scale mitigation requirements TLP anticipate will arise from tidal lagoon development.
  3. To foster innovative and collaborative partnerships to deliver conservation action in the UK, EU and globally.

To achieve these aims, the EEP has six strategic objectives that focus on the creation of large areas of mudflat, saltmarsh and grazing marsh; initiatives to support habitat restoration efforts for migratory and resident fish; and other biodiversity enhancements, for example, by enabling changes in land management practices. The delivery of the EEP will be phased to ensure that resources are directed towards priority areas of work and achieve real results on the ground or ‘in the mud’, so to speak. The compensation and ecosystem scale mitigation TLP anticipate will need to be associated with Tidal Lagoon Cardiff (TLC) is currently being investigated – TLC is TLP’s most advanced lagoon in planning and assessment terms.  Confidence is now high, based on strong case study evidence, that intertidal habitat can be created that outperforms its targets. For example, Allfleets Marsh in the Crouch Estuary exceeded its bird assemblage targets (themselves based on predicted losses) by 200% five years post breach; and the Trimley Marshes managed realignment site in the Orwell Estuary was included with the Stour and Orwell Estuaries SPA inside five years. Moreover, significant opportunity exists to create high quality functional intertidal habitat and enhance subtidal habitats in England and Wales, with research indicating that around 109,000ha of coastal, largely arable, land in England and Wales that could be reinstated as coastal wetlands.

With the opportunity that lagoons provide to be conservation enablers, comes a responsibility to ensure that the best outcomes for nature conservation are delivered. A key aspect part of this requires that TLP works collaboratively with likeminded organisations in order to be pioneering and outcome focused vis-à-vis biodiversity. To this end a governance board will be established over the coming year for the EEP with an independent chair to act as a ‘critical friend’.

Polar explorer, Robert Swan, said that “The greatest threat to our planet is the belief that someone else will save it”. We don’t yet know whether the UK’s exit from the EU will mean change for UK conservation but we do know that the EU will no longer drive and underpin the UK’s conservation agenda. If ever there was a time for action to combat climate change and big bold partnerships, it is now. TLP is up for the challenge, who wants to join us?

Wallasea 331_TLP image credit
Wallasea Photo: TLP



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4 Replies to “Guest blog – Time for tidal power by Sian John”

  1. Really interesting blog, thanks for sharing it.
    What a great thing it would be if ALL development, whether on land or sea, had among its aims to be net positive for biodiversity – and to be able to have confidence in that actually happening based on sound evidence provided by case studies with an independent assessment to show ‘conservation enablers’ that deliver real results for different habitats and species. Much more than just tokenistic ‘offsetting’, such as Paterson’s ludicrous assertion that you could replace an ancient woodland with a plantation – and where progressive developers, conservation organisations and local communities could work together to achieve good outcomes for nature as an integral part of the development not just an ‘optional extra’.

  2. I have just been involved trying to save Carlisle from flooding especially with ‘water catchment’ areas. Sadly my MP also Defra Minister prefers dredging the SSSI rivers. Note that down stream an area of 100 acres is created every year due to the amount of sediment coming down the rivers and that does not include sediment washed further out into the Solway! Will this sediment just fill in the dredged areas!!

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