The tide is turning for tidal?

[Oldgreybeard]

I don't think being in phase with demand matters, does it? From what I remember of looking around Rance it works both ways. Only issue is how they deal with the dip during the change over period. Several lagoon type systems would solve this, they could be phased to give 24/7 generation, even if working in the same tidal area, I think.

[Mart]

I don't think being in phase with demand matters, does it? From what I remember of looking around Rance it works both ways. Only issue is how they deal with the dip during the change over period. Several lagoon type systems would solve this, they could be phased to give 24/7 generation, even if working in the same tidal area, I think.

Hiya. Yes and no. Being in phase with demand, and ideally demand following are really useful, especially if most of the RE gen isn't, such as PV and wind that is less reliable on a daily basis.

But, I think with 14 out of 24 hours covered, and with relatively short breaks between, then like you I don't see an issue. Plus these lagoons will be able to demand follow partially, though the net result is a loss of energy - They can start generating sooner than ideal, for instance, if the lagoon is empty, instead of waiting for the tide to peak in height before opening the turbines (maximising the height differential), they can open a bit earlier. This will mean less power, and less energy in total for that cycle, but may be a useful trick. The same again on a discharge cycle, before the tide is at its lowest.

Obviously I'm talking individual lagoons. As a package they should be able to overlap somewhat.

[Oldgreybeard]

Why do they only work 14 hours out of 24, though? From what I remember of the trip around the Rance plant, years ago, there were just a couple of hours when the tide turned each day when the power dropped. The generators are bidirectional, so generate when the tide's coming in as well as going out, and so it's only the lull between changes when it stops working. From what I remember they minimise that by retaining water in the lagoon for a time when the tide is on the turn having gone out, so the output reduces slightly, and do the reverse when the tide is coming in, by not allowing the lagoon to fill too fast.

[Mr Gus]

Thing is, we are a fast growing connected island, someone always wants the spare (it helps base levels & tick over) ..its not like folk are stopping reproducing so if viable & if it doesn't decimate marine / aquatic dependent flora & fauna, & as battery storage is now more "here" & not beyond the horizon, & as part of forward planning, low carbon production & doubtless incoming EU wide (members or not) insistence to not sleepwalk into another putin, gas & oil scenario that has put us all on our arses, then is it viable?

There is a limit to how many off & onshore wt's we can erect for a variety of reasons (full order books being just one) ..so as part of the mix ..big new steps?

How many estuary power sites are mapped as significant potential? (presumably govt knows) ..we even have a bit of wash tidal at the likes of wisbech (old port area)

http://www.portofwisbech.co.uk/

Nb anyone interested in Dickens should visit on a Saturday morning the museum when they pull out a manuscript for close inspection

https://www.edp24.co.uk/lifestyle/20811 ... find-copy/ ..Spoons nearby for a good breakfast & warmth.

It is also the "architects wet dream" of incompetent design over function pertaining to renewables with its "boat shape" offices & non functioning expensive vawt mast.

I increasingly look at big battery storage alongside WT's & other periodic renewables, wave, solar, as a renewable "catch & release" investment yes, but every project is, ..a uk battery factory wont change the market potential unless it happens either.

[Stig]

If you want to chuckle at something with even less hope of happening than a Severn barrage:
https://www.bbc.co.uk/news/uk-england-l ... e-63708269

[Mart]

Why do they only work 14 hours out of 24, though? From what I remember of the trip around the Rance plant, years ago, there were just a couple of hours when the tide turned each day when the power dropped. The generators are bidirectional, so generate when the tide's coming in as well as going out, and so it's only the lull between changes when it stops working. From what I remember they minimise that by retaining water in the lagoon for a time when the tide is on the turn having gone out, so the output reduces slightly, and do the reverse when the tide is coming in, by not allowing the lagoon to fill too fast.

Yep, as you say, a couple of hours as the tide turns, so that's the four 2.5hr periods between generation. That gives the max power and energy, but it can be fiddled with slightly to widen the generation period, but at a cost to power and energy for that cycle.