Severn Tidal Power Feasibility Study facts for kids

The Severn Tidal Power Feasibility Study was a project by the UK Government. It looked into using the huge tidal range (the difference between high and low tide) in the Severn Estuary and Bristol Channel to make electricity.

The study started on January 22, 2008. It was led by the Department for Energy and Climate Change. The Welsh Assembly Government and the South West Regional Development Agency also helped.

Older reports about tidal power in the Severn didn't fully explore all the ways to use tidal range. This study aimed to look at all options, including large dams called barrages and smaller enclosed areas called lagoons. The Severn Estuary has the second highest tidal range in the world, with tides rising up to 14 metres. This means it could create a lot of clean electricity. It could even generate up to 5% of the UK's electricity. This would help the UK reach its climate change goals and the European Union's renewable energy targets.

The government did this study to understand all the costs, benefits, and effects of a Severn tidal power project. People often mistakenly called it the Severn Barrage. But the study looked at many different technologies, not just barrages. After a lot of discussion, the government decided not to support a public project. However, it didn't stop private companies from trying to build one.

The first public discussion for the study happened from January 26 to April 23, 2009. It focused on what the study would cover and which projects would be looked at more closely.

What is the Severn Tidal Power Study?

Why study tidal power?

People have suggested building dams or barrages in the Severn Estuary since the 1800s. At first, it was for things like transport and flood protection. But in the 1970s and 80s, studies looked at using the estuary to make electricity.

In 1989, a government report called 'Energy Paper 57' came out. It said that a project to make electricity as the tide goes out (called 'ebb generation') between Lavernock Point and Brean Down was possible. This project, known as the Cardiff-Weston barrage, could make about 17 terawatt hours (TWh) of electricity each year. But back then, the government decided it was too expensive. So, the plans were put on hold.

You can find a full history of these plans at Severn Barrage.

What did the study aim to do?

The main goal of the study was to gather information. This information would help the government decide if it should support a tidal power project in the Severn Estuary. The study built on past research and gave an updated look at all the important issues.

The study focused on six main areas:

• Environment: How it would affect animals, plants, and their homes. Also, flood control, water quality, and the look of the landscape.
• Engineering and Technical: How to design and build the projects, how much they would cost, and how they would connect to the national electricity grid.
• Economic: How to pay for the projects, who would own them, and how they would affect the energy market.
• Regional: How the projects would affect local businesses and the economy in the area.
• Planning and Permissions: What rules and laws needed to be followed to get approval.
• Talking to People: How to involve and communicate with everyone who had an interest in the project.

The study lasted about two years, ending in 2010. It had two main parts. The first part ended with a public discussion in early 2009. This part looked at the big picture and a short list of 10 possible tidal power projects. After getting feedback from the public, the second part of the study continued. At the end of the second part, there was a final public discussion. Then, the government made its decision. They looked at the costs, benefits, effects, and risks of a Severn tidal power project.

What is an environmental assessment?

As part of the study, a Strategic Environmental Assessment (SEA) was done. An SEA is a formal check of how big plans or projects might affect the environment. The results of this check are put into a special report.

Proposed projects

In July 2008, a list of ten possible projects was shared. The study looked at these ten projects in more detail. In January 2009, the study suggested a shorter list of 5 projects for closer research in the second part of the study. These 5 projects were:

• Shoots Barrage: A 1.05 gigawatt (GW) project located near the new Severn road crossing. It was estimated to cost about £3.2 billion to build.
• Beachley Barrage: A 625 megawatt (MW) project located further upstream, near the first Severn road bridge. It was estimated to cost about £2.3 billion.
• Bridgwater Bay Lagoon: A 1.36 GW enclosed area on the English side of the Estuary. It was estimated to cost about £3.8 billion.
• Fleming Lagoon: A 1.36 GW enclosed area on the Welsh side of the Estuary. It was estimated to cost about £4.0 billion.
• Cardiff-Weston Barrage: This was the largest project, an 8.46 GW scheme from Lavernock Point to Brean Down. It was commonly called the 'Severn Barrage' and was estimated to cost about £20.9 billion.

In July 2009, the government confirmed that these 5 projects would be studied in more detail. They also announced that three other projects, which were still in very early stages, would be looked at.

A 2009 report by Atkins suggested that the most power could come from a barrage between Ilfracombe and Gower. This location is much further west than the projects the study looked at. This new idea came from using different calculations than previous studies.

Project timeline

• April to Autumn 2008: The study first looked at the big issues and possible tidal power options.
• Late 2008: The government decided if there were any major problems that would stop the project.
• January 2009: A public discussion started. It asked for opinions on the short list of projects and how they were chosen. It also discussed what the environmental assessment would cover.
• Spring 2009: The second part of the study began. Based on public feedback, the issues were looked at more closely. The short list was made final, and the best option or combination of options was chosen.
• 2010: There was a final public discussion about the study's findings. After this, the government decided whether to support a tidal power project and under what conditions.
• After 2010: The government decided not to invest public money in a Severn tidal energy project. However, they said that a project funded by private companies could still happen. If a project were to go ahead, a lot more detailed planning and work would be needed to get all the necessary permissions.