Opponents and supporters of a barrage across the River Severn are being given the chance to put their views to a council-run debate.
The Severn estuary has the world's second-highest rise and fall of tides
Those in favour say it could generate up to 7% of the UK's electricity but critics say it would have a "devastating effect" on wildlife.
A Gloucestershire County Council spokesman said the debate aims to get people talking and help form opinions.
"Many have an opinion but haven't heard both sides of the argument," he said.
The meeting will also hear presentations about renewable energy, tidal technologies and climate change and its effect on the South West.
Council leader Barry Dare said: "We expect a clearer position on the realities of the barrage or other energy options such as offshore turbines in the channel.
"There may also be a lobbying position coming out of it, so we can send a very clear message to government that Gloucestershire and the South West is serious about climate change and doing something about it," he said.
The Severn Estuary, which has the second largest tidal ranges in the world, has often been suggested as the "ideal place" for a barrage to make use of the massive amounts of energy formed by the rise and fall of the tide.
But environmentalists say a barrage would cause "irreversible damage" to wildlife.
The estuary is a special area for conservation and provides food for more than 63,000 migratory and wintering water birds.
The invitations-only conference was due to take place on 1 November.