OT: Swansea Tidal Lagoon rejected

[alan_m]

So between high and mid tide (approx 3 hours, twice a day) no power is generated - or the generation is very inefficient.

Also consider the difference in the height of the water on either side of the barrage. Once you have enough head of water you can open the gates and start generating but the at of doing so changes the height of the water in the lagoon reducing the head of water and the efficiency of generation.

There are probably other considerations regarding the quality of the water in the lagoon based on the rate that it is filled and emptied.

A continual low flow of water is likely to result in a fast build up of silt. This is an area with nearby shifting sand bars and each tide will carry this and. Still water will drop the silt whilst a fast flow/current is likely carry the silt with it.

The lagoon will be situated adjacent to a river outflow. In times of heavy rainfall the water in the river is likely to be nutrient rich due to farmland runoff of sewage overflows. This nutrient rich water is likely to flow to the barrage inputs at some time and needs to be flushed out fast on subsequent tides. A nutrient rich lagoon seabed is likely to result in massive algae growth which could cause problem both environmentally and for the turbines/filters.

[The Natural Philosopher]

the energy stores is directly poroprtional to the head. Halve the head, halve the power and the energy. And the profit

Try 'reservoir'

You are of course talking handwavey nonsense. Because 'can' does not equal 'profitably and efficiently, can'...

I can design a car with square or egg shaped wheels...

So what? All you have done is take a bad idea and make it worse by lowering its output massively in order to meet a criteria of 'non-intermittency'.

You might as well put a couple of lead acid battries on a 2MW windmill and then only use it to 1% of its potential in order to get 'constant power'

This is handwavey crap.

ALL that counts in power generatiuon is cost per unit reliable delivered electricity generated, and that cost must include externalities like environmental impact and if you believe it has a cost at all, rather than a benefit, carbon emissions.

For example, let's put greens on treadmills. It will generate reliable energy 24x7. And reduce obesitity.

Its possible that over a day you might get 400 watt hours out of a human being, So at current market rates you could afford to pay them 4p a day.

That wont even buy them the food they need to stay alive. Hooray! you may say, as morally that is a good idea, but its not economically viable.

'could' is a word that should be banned along with the phrase 'I think'

[T i m]

Good luck to you being able to understand how to get a iTPMS system to work with that (given you don't get it with round wheels)! ;-)

Cheers, T i m

[news17k]

[...]

I described a simple way in which the claimed intermittency of tidal generation could be avoided. That there might be some engineering trade-offs with implementing such a scheme is hardly a remarkable observation. Further, there is no reason for such a scheme to lower by any significant fraction the overall (per-tidal cycle) energy output of the scheme.

#Paul

[Chris Hogg]

The only linked-basin tidal plant in the world is the Haishan plant in China, in operation since 1972, so there's nothing new in the idea.

It produces 0.25MW continuously.

There must be a reason why it's not been done anywhere else.

[alan_m]

Possibly..... "So when this power station is in operation, its sedimentation is so serious that it has silted up 63cm during eight years"

Its a similar problem with some dams on rivers providing hyroelectric power.

[dennis]

Do you believe in perpetual motion too. The only way to avoid the intermittency of tidal is to have alternative generation capacity. If you want pumped storage then you may as well build it in the hills where it will be easier and have a better head.

[T i m]

Not since Brexit they wouldn't. ;-(

Cheers, T i m

[Chris Hogg]

Hmm...I suspect the sedimentation problem is more to do with the specific location.

But I note Haishan has a capacity factor of only 15.6%. This compares with La Rance at 26%* and that anticipated for the Swansea scheme of

19%**. I suspect double-lagoon tidal systems are just too expensive and too inefficient to justify constructing on a scale big enough to produce decent amounts of power.

** Mearns does a pretty good demolition of the case for the Swansea Bay barrage in that link.

[The Natural Philosopher]

I see you havent actually followed the arguments.

Fairly typical for a faith basesd renewable troll.

[The Natural Philosopher]

20 years ago you would have said te same about windmills.

And been right.

Its all virtue signalling rent seeking and profiteering.

Never about actually lowering CO2, because - guess what - they actually don't.

[whisky-dave]

ARSES Advanced Rail Storage Energy System

so I've re-arrange it slightly.

[Chris Hogg]

Shouldn't that be bbc.co.uk/news/av/technology-44549962/surplus-energy-rides-the-gravy-train?

Mearns has a detailed discussion on the proposal

[alan_m]

In the UK it will result in even more intermittent power with the wrong type of leaf or the wrong type of snow on the track.

[Vir Campestris]

You build another in Morecambe Bay, where the tides are nicely out of synch. Plus a grid upgrade to move the power about. That way you spoil two bits of environment for the price of one.

Or build a nuke.

Andy

[Chris Hogg]

Er...no. It's a popular myth. They're almost six hours out of synch, so high tide at one corresponds to low tide at the other, i.e. slack water at the same time in both places.

See

and

Mearns' comment in the second link: "In fact, UK tidal lagoons will produce more intermittent electricity than any other form of renewable generation providing four spikes separated by four periods of zero production each day. It is often claimed that the predictability of tides is a virtue. This also means we can predict with certainty that this energy source will be a disaster for the public as well as the environment."

Now you're talking!

[Vir Campestris]

I sit corrected.

It looks as though there might be a bit of the Severn that would pair up

- but I still prefer the nuke.

Andy

[Bill Wright]

So voting to leave makes me a racist does it?

Bill

[dennis]

Other things you have said makes people think you are racist. So you probably did vote leave because of racism.

Others may have voted on other grounds but a lot did so because they want to get rid of the "immigrants" and they are too stupid to know the EU lot are migrants and leaving the EU will increase immigration not reduce it.

We will need even more immigrants to replace the migrant workers that aren't allowed in from the EU. Immigrants usually bring their families with them so the net increase will be substantial.

Of course brexiteers can't work this out as they assume the government is as racist as they are and will stop immigration, like they have done so in the past!

[T i m]

Are you a racist and pub EU expert who voted leave?

What is it about leavers though that makes them inclined to always pick up the wrong end of the stick?

(As with the whole Brexit farce in fact).

"Oh, I thought voting leave would mean we actually leave the EU and everything every Leave voter also thought it meant ... 100%"

That does seem to be the case as no Brexiteer has stated what percentage of all of those facets it would need to still count as an actual 'leave'.

Cheers, T i m