The tide is turning for tidal?

[dan_b]

Nice to see some media coverage for tidal stream turbines

https://www.theguardian.com/environment ... lity-flows?

[nowty]

I've seen this before but the picture of it on the surface just does not do it justice, until you see what's underneath.

[Mart]

I'm sure I've seen that before - Star Trek 4 - The Journey Home ...... when they 'parked' a Klingon Bird of Prey in the sea?

What a rip off!

[Oldgreybeard]

It's a clever bit of design, as presumably the arms can be pivoted up for relatively easy maintenance of the turbines. It's always seemed to me that reliability and ease of maintenance are the key problems that need to be solved for free stream tidal power. The sea takes no prisoners when it comes to constantly break everything down to its constituent molecules.

[Petertc]

I've been following this for a while, they seem to have got things pretty well sorted.... But mother nature can through a curve ball

[Oldgreybeard]

The HVDC thread was drifting to this, so I've moved the tidal debate here instead.

I'm not convinced of the Environmental reasons for not having Tidal barrages? sounds too much like big oil and Gas using the environment to save their monopoly.

Environmental arguments never stopped London getting their none generating barrage did it - No because there was a vested interest for the politicians so it got built.

Doesn't matter how you wrap it up theres a massive hydro/tidal opportunity not being used and whatever the negatives of such systems are they are a whole lot better than CCGT's coal fire power stations and nuclear.

Whats the environmental impact of the last 60 years of nuclear power generation ? How can they square the environmental argument of the yet to be built long term geological repository for nuclear waste ??

The reality is its easy to build easy to maintain and easy to replace tidal barrage equipment - the main issue is its a big outlay and long return on investment and the conservatives don't do investment they expect others to do it for them and because its along payback there's not much chance of a kick back is there.

Well that's my rant for the month over and I feel SOOOOOO much better thanks

Moxi

What we often seem to forget is that our beautiful environment is quite often a result of previous generations industrialisation of the countryside.

How glorious would the Yorkshire dales be without farming to maintain it? How did the new forest come to be like it is ? Most of our rivers and estuaries are shaped by mans intervention be it for drainage or improved access, the Fens ? Somerset flats etc etc etc.

If people want the natural environment unspoilt by man then its going to be a very dark dense forest with generally poor ground habitat due to the high shaded canopy with the odd "island" of light where older trees have died as per some of our ancient woodland that survives.

There absolutely no MORAL reason why we cannot build necessary infrastructure that runs harmoniously with the natural environments needs.

Theres an abundance of IMMORAL reasons why necessary infrastructure isn't built none of which is directly attributable to the natural environment BUT much of which seeks to hide behind green environmental arguments. A politician that says its not environmentally sound is actually saying we don't want to spend the money that's actually required to do this in an environmentally considerate manner.

Moxi

I'd start by stating that I'm a strong believer in tidal power, and was pretty much obsessed by the idea after a sailing holiday around Brittany that included a trip to the one at Rance (this one: https://en.wikipedia.org/wiki/Rance_Tidal_Power_Station). I've followed the long and chequered history of the proposed Severn barrage (about the only viable large power generation capability location in the mainland UK) for over 40 years now.

I wanted to believe it was both practical and achievable, but the evidence of the environmental damage it would cause, even long distances away up the Wye and Severn rivers and their flood plains, has finally convinced me that it most probably isn't as great an idea as it seems. The population affected by likely flooding alone is now very large, thanks to many more houses having been built on the flood plains affected by the Severn.

Had the barrage been built when first envisaged, over 150 years ago, then I am sure we could have adapted it and changed the way land was developed in areas where the Severn regularly causes winter floods. The eight (now I think nine) attempts to look again at the viability of a Severn barrage have all concluded, for various reasons, that it's not a goer. Undoubtedly there was undue weight placed on some factors by opponents, and that most probably did change the outcome of many of these earlier projects such that they were cancelled.

The major, and seemingly insurmountable, problem is the winter flood risk. Any barrage across the whole of the Severn would make the existing very high flood risk worse, with no practical way to mitigate it. Vast amounts of water and sediment flows into the Severn at times every winter, and more often than not floods thousands of acres of land along the banks of the river, even when the tide is out the flood water doesn't drain away fast enough. The economic and environmental damage this flooding causes is mad-made - we should not farm or build on this land. However, it's too late to change that, we cannot just relocated tens of thousands of people. A whole barrage across the Severn would also create a massive 24/7, 365 days a year, dredging job, around 6 million tonnes of silt would need to be dredged out of the lagoon every year and deposited somewhere.

The alternative options looked at, that don't block the Severn (or Wye) drainage to the same extent suffer from other problems, not least being that the economics don't stack up because the potential energy generation is so much lower.

Much as I hope that the latest project that's looking again at a Severn barrage scheme finds solutions to the problems, I'm afraid that I'm not hopeful that it will. It's a great shame, as many years ago I surfed the the Severn bore with some friends, and was astounded at the power in that flow of water (and mud - it's very, very, very muddy!).

[dan_b]

I actually put some money into the Atlantis Tidal project off Orkney via Abundance Investment - the technology is definitely starting to get there. The sea has a habit of absolutely munching any machinery that's installed in it if it wants to, and I guess a problem with a fast moving tidal stream is the sediment and debris that gets driven along as much as the water itself?

[dan_b]

Not sure how this device works, more digging required

https://renews.biz/81476/scots-wave-ene ... l-results/

[Mr Gus]

I see Wales, Swansea Bay £1.3 billion tidal power lagoon has lost its planning appeal (5 year building timeframe is up) 16 turbines **up to** a supposed 320 megawatt hours per day.


Court decision, been in legal limbo since march 2022, Welsh govt & parliment think it doesn't offer value for money, ..wonder if ukraine / orc invasion has changed that view compared to "burn everything" figures & market trauma?

An ok piece on various tidal in New civil engineer. (links to other welsh & scottish tidal power plans within)

https://www.newcivilengineer.com/latest ... 7-12-2022/

[Oldgreybeard]

The Russian hostility that has exposed our vulnerability to being beholden to a rogue state has indeed started another review of the Severn options. Not sure if the outcome will be any different to the many times this has been looked at in the past, though.