The list unveiled by the UK Department of Energy and Climate Change includes a mixture of barrages and innovative lagoon schemes.
Energy and Climate Change Secretary Ed Miliband has also announced £500,000 of funding to further develop embryonic technologies like tidal reefs and fences.
The proposed shortlist includes:
Cardiff Weston Barrage: A barrage crossing the Severn estuary from Brean Down, near Weston super Mare to Lavernock Point, near Cardiff.
