Feasibility Stage 1

A prime objective of Stage 1 of the feasibility study was to ensure that all the different possible types of tidal energy conversion device were examined. Devices for use in both deep and shallow water were included, as were technologies ranging from innovative and emerging through to fully mature.

Candidate technologies were gathered together using the knowledge and experience of the team members, the findings of the Mersey Tidal Power Phase 1 (see pre-feasibility study section) and the findings of the much earlier Mersey Estuary tidal power studies.

Also key to the study was information on several tidal power schemes either in operation or being pursued in various parts of the world.

Of particular interest to the Mersey Tidal Power project is the work being done to assess tidal power generation in the Severn Estuary in the UK.

Evaluation Criteria

Once the full list of candidates had been drawn up, each one was evaluated against five selection criteria:

1. Estuary width and water depth
Can the technology be implemented in the Mersey Estuary, given its width and water depth, while limiting any impacts to acceptable levels, if necessary by adjusting the size of the scheme or modifying the operating conditions?

2. Water velocity
Will the technology be capable of generating a commercial quantity of energy from the natural tidal current velocities in the estuary?

3. Performance parameters
Has the performance of the technology been sufficiently studied to enable its energy output to be assessed?

4. Technology maturity
Will a prototype of the technology have been sufficiently tested (or will there be the technical and financial capacity to undertake such tests) in representative conditions, including adequate flow magnitude, physical scale and marine conditions, in time for the technology be adopted as the basis of a commercial scheme in a planning application in late 2011?

5. Delivery
Will the technology have the support of a company with sufficient technical capability and financial security to enable it to be adopted as the basis of a commercial scheme in a planning application in late 2011?

Feasibility Stage 1 Results

The study team examined a total of 14 technology options.  At the end of Stage 1, four of these 14 options made it on to the long list.

The four main technologies to be considered in Stage 2 are as follows:

  • horizontal-axis turbines in an impounding barrage
  • a tidal gate comprising Hydromatrix turbines and creating a very low-head barrage
  • vertical-axis, cross flow or horizontal-axis, ducted stream flow machines in a tidal fence
  • a SMEC forming a tidal fence.
  • For more information on each of these technologies and more, click here.