Severn Tidal Power Feasibility Study

Severn Tidal Power Feasibility Study is the name of a UK Government project looking at the possibility of using the huge tidal range in the Severn Estuary and Bristol Channel to generate electricity.

The tidal range in the Severn Estuary is the second highest in the world and can rise as much as 14 meters, [cite web | url= http://www.environment-agency.gov.uk/commondata/acrobat/severnpositionmay2006_1508223.pd | format= PDF | work= UK Environment Agency | title= Severn Estuary Barrage | date= 31 May 2006 | accessdate= 2008-08-28 ] meaning it has the potential to generate more renewable electricity than all other UK estuaries. This could create up to 5% of the UK’s electricity, contributing significantly to the UK’s climate change goals as well as the European Union's renewable energy targets). [cite web |url=http://nds.coi.gov.uk/environment/fullDetail.asp?ReleaseID=366554&NewsAreaID=2&NavigatedFromDepartment=True |title=Severn tidal power feasibility study: BERR appoints contractors
accessdate=2008-08-27 |work=BERR]

As part of the project, the Government is carrying out a feasibility study to look at all the costs, benefits and impacts of a Severn tidal power scheme. The study, often incorrectly called the Severn Barrage, looks at all tidal range technologies - including barrages, lagoons as well as other technologies. A decision whether the Government will support the scheme or not will take place after a public consultation in 2010. [cite web |url= http://new.wales.gov.uk/topics/environmentcountryside/energy/severntidal/?lang=en |title=Severn tidal power | accessdate=2008-08-27 |work=Welsh Assembly Government]

History

Previous schemes and studies

Proposals for damming or barraging the Severn Estuary (and Bristol Channel) have existed since the 19th century for reasons such as transport links and flood protection. [cite web | url=http://r-energy.co.uk/history.html | work=R-Energy | title=History of Severn Barrage | accessdate=2008-08-28] In more recent decades however, (1970s and 80s) there were a number of studies considering barraging the Severn estuary for electricity generation reasons. These studies concluded in 1989 in the government policy document 'Energy Paper 57', [cite web | url=http://www.publications.parliament.uk/pa/cm199899/cmselect/cmenvtra/171/171m22.html | format=PDF | work=UK Parliament | title=The UK Climate Change Programme | date=5 January 1999 | accessdate=2008-08-28 ] , which found that an ebb generation scheme (one that generates electricity as the tide goes out) between Lavernock Point and Brean Down, known as the Cardiff-Weston barrage was technically feasible. The annual output of electricity was estimated at approximately 17 terawatt hours (TWh). However, at the time Government decided a Severn Barrage was not a cost-effective option for generating electricity and plans were shelved.

A comprehensive history of studies and plans for a Severn Barrage can be found under Severn Barrage.

The Energy Review and the Sustainable Development Commission study

In May 2006, with the growing evidence of climate change and rising fossil fuel prices, the Government called for a new in-depth study into the potential for tidal power from the Severn. The Sustainable Development Commission (SDC), the Government’s independent advisory body on sustainable development, was commissioned to look at the issues arising around tidal power, with a particular focus on the Severn Estuary. Their study 'Turning the Tide: Tidal Power in the UK'. [cite web | url= http://www.sd-commission.org.uk/pages/tidal.html | format=PDF | work=The Sustainable Development commission | title= Tidal Power| date=1 October 2007 | accessdate=2008-08-28 ] , concluded that:
* The Severn Estuary tidal range can generate some 5% of UK electricity;
* the Severn Estuary (and Bristol Channel) tidal stream resource is not one of UK top ten sites;
* a barrage can be built that meets the principles of sustainable development but it must comply with the Habitats Directive and other environmental legislation in force;
* Government needs to carry out an 'appropriate assessment' using up-to-date techniques to understand the impact;
* a large tidal power generation system could be viewed as an 'environmental opportunity' - combining climate change mitigation (energy without CO2 emissions) with adaptation (funding potential for a compensatory habitat); and
* Her Majesty's Government should own and lead the project.

The Feasibility Study

On 22 January 2008, the Government launched a feasibility study [cite web | url= http://news.bbc.co.uk/1/hi/sci/tech/7013068.stm| work=BBC News| title=New Study for Severn Energy Plan | date=25 September 2007 | accessdate=2008-08-28 ] , As the SDC report did not - and did not aim to - provide a detailed analysis of all tidal range technologies, the feasibility study aims to considers all tidal range technologies, including barrages and lagoons. The focus is on tidal range technologies as this is where the energy potential in the Severn Estuary is the greatest. Tidal range is the vertical difference between the highest high tide and the lowest low tide (up to 14 metres- 42 feet - in the Severn Estuary); as opposed to 'tidal flow' which is the current in moving tidal waters. The study is being lead by the Department of Business, Enterprise and Regulatory Reform (BERR) and includes representation from the Welsh Assembly Government and the South West Regional Development Agency.

Aims of the Feasibility Study

The study aims to gather and examine evidence which will enable Government to decide whether it could support a tidal power scheme in the Severn Estuary and if so, on what terms. Building on past studies, the feasibility study will provide an up-to-date overview of all the key issues involved.

There are six key work areas which will be looked at closely in the study:
* Environmental - impacts on biodiversity and wildlife; flood management; geomorphology (the study of the evolution and configuration of rocks and land forms); water quality; landscape; compensatory habitat;
* Engineering and technical - options appraisal; costs; design and construction; links to the National Grid;
* Economic - financing; ownership; energy market impacts;
* Regional - impacts on business; regional social and economic impacts;
* Planning and consents - regulatory compliance; and
* Stakeholder engagement and communication.

The study will run for roughly two years (until 2010) and will be a two stage process with a decision point at the end of each. The first stage, likely to run until late 2008, will focus on the high level issues and will short-list potential tidal power project options from the 10 schemes that are currently being looked at. [cite web | url= [http://www.renewableenergyworld.com/rea/news/story?id=53278 | work=Renewable energy World.com | title=UK Government Releases Severn Government Proposals | date=11 August 2008 | accessdate=2008-08-28] At the end of this stage a decision will be made on whether there are any fundamental issues that mean the project cannot proceed and that would prevent the Government from supporting the project, or alternatively if no issues are found, the gathering of evidence and assessments would continue.

Strategic Environmental Assessment

As part of the feasibility study, A Strategic Environmental Assessment (SEA) will take place. An SEA is a formal environmental assessment of plans or programmes which are likely to have significant effects on the environment. The assessment is produced in the form of an environmental report. At the end of the first stage of the feasibility study, if the decision is taken to continue, a consultation on the findings of the Strategic Environmental Assessment (SEA) and short-listed project options will then take place. [cite web | url= http://www.berr.gov.uk/energy/sources/renewables/explained/severntidalpower/strategicenvironmentalassessment/page47489.html | work=BERR | title=Strategic Environmental Assessment | accessdate=2008-08-28 ] [cite web | url=http://www.wales.gov.uk/severntidal | work=Welsh Assembly Government | title=Strategic Environmental Assessment | accessdate=2008-08-28]

10 Proposed Projects

A list of 10 proposed projects was published in 2008. The feasibility study will look in further detail at the 10 schemes. A short-list will be published towards the end of 2008 highlighting preferred proposals which could be taken forward for more extensive research in phase two of the study.

* Outer Barrage from Minehead to Aberthaw: this would be the largest barrage and would make maximum use of the Severn Estuary tidal resource.
* Middle Barrage from Brean Down to Lavernock Point: most well-studied option, known as the Cardiff-Weston barrage.
* Middle Barrage from Hinkley to Lavernock Point: as option 2 but lands at Hinkley
* Inner Barrage (Shoots Barrage): also known as English Stones scheme and studied in detail by the Sustainable Development Commission.
* Beachley Barrage: barrage further upstream, smaller generating capacity than Shoots.
* Tidal Fence proposal: a barrier constructed over part of the Cardiff to Weston line, with open sections, incorporating tidal stream turbines to capture energy from the ebb and flood tides.
* Lagoon enclosure on the Welsh grounds (Fleming lagoon): one of the previously studied Russell lagoons from 1980s.
* Tidal lagoon concept: a proposal for a number of tidal lagoons.
* Tidal reef proposal: an environment friendly concept that employs a large number of low head, fish friendly turbines to increase the generation period and reduce the impact on wildlife. The turbine caissons would be floated into place over a low cost causeway structure.
* Severn Lake Scheme: a 1 km wide barrage in the same location as the Cardiff-Weston scheme designed to allow the construction of a number of additional features, including a wave farm on the seaward side and four marinas.

Timeline

"April to Autumn 2008" - Initial focus on the high level issues and potential tidal power options assessment.

"Late 2008" - Government decision on whether there are any issues that mean the project cannot proceed. Subject to the decision, a public consultation will be held also bringing into the results of the Strategic Environmental Assessment and a short listing of tidal power options will be made.

"Late 2008 to early 2009" - Second phase. The issues to be considered in more detail, and narrowed down to preferred options.

"2010" - Public consultation on the evidence and conclusions of the study. Following the consultation, Government will make a decision on whether it could support a tidal power scheme, and if so on what terms.

"Post 2010" - If the outcome of the feasibility study is a decision to proceed, extensive and further detailed work would be needed to plan and implement a tidal power project, and secure the regulatory consents that would be required.

External links

* [http://www.berr.gov.uk/energy/severntidalpower Department for Business Enterprise and Regulatory Reform – Tidal Power: Severn Estuary]

* [http://www.wales.gov.uk/severntidal Welsh Assembly Government Severn Tidal Power]

* [http://www.sd-commission.org.uk/publications.php?id=607 Sustainable Development Commission, Turning the Tide: Tidal Power in the UK paper]

References