Hinkley Point C - C stands for CON

[wobs]

You still haven't been able to think of any time when GB has no tidal energy.

That's because there isn't one.

The three biggest potential sites for barrages in the UK and tide times for today:

Heysham (for Morecambe Bay – Max 3GW)
29/6/17
03:42 8.6m
10:24 1.5m
16:13 8.0m
22:43 2.1m

Cardiff (for Seven Barrage – max 13.2GW)
29/6/17
04:39 1.72m
10:45 11.10m
16:59 2.15m
23:08 11.00m

Solway Firth (Max 7.2GW)
29/6/17
04:01 8.23
10:45 1.08
16:31 7.72
22:53 1.62

All three are fairly in line with each other, albeit with one on the opposite tide

See Table2 here for potential sites:
https://www.gov.uk/government/uploa...y_Conclusions_and_Summary_Report_-_15_Oct.pdf

The next largest are Wash (2.4GW), Humber (1.08GW) & Thames (1.12GW). None of which should really be considered due to shipping and/or ecological reasons, and are all substantially less than what you would need to balance any variations in the Seven barrage.

Meanwhile, tidal turbines offer far less potential, so would not offer any substantial balance elsewhere.

This also ignores the SSSI status of any of the estuaries, and the added flood risk, as mentioned here:
"The primary impact of the barrages is the increased flooding risk, due to the increase in tidal amplitude of 0.15m to 0.20m along the east coast of Ireland and Northern Ireland."
https://www.publications.parliament.uk/pa/cm201314/cmselect/cmenergy/194/194we23.htm#footnote_47
From a lengthy study here:
http://ukerc.rl.ac.uk/pdf/Tidal_Power_Irish_Sea_Final.pdf

Basically, there are limited sites, and those that offer potential would not balance each other out. We would need other reliable sources such as gas or large biomass plants to address the demand changes and variations in tidal output.

Make no mistake though, I'm not against such schemes in general, but its not so straight forward, and they are only part of the solution. We need nuclear power for baseload supply.

 

[JohnD]

I can see plenty of tide tables.

Are you going to tell me a time today when you think the UK has no tidal energy available, which is what I've repeatedly asked for?

 

[wobs]

I can see plenty of tide tables.

Are you going to tell me a time today when you think the UK has no tidal energy available, which is what I've repeatedly asked for?

I've shown you a chart:

Which shows that tidal is intermittent even when multiple facilities are used.

The tide times give you an idea of the tide times for the main sites proposed. It shows that the times approximately coincide with each other, and the cycle of each barrage would not compensate for each other as a result. Although I would put more faith in the chart above, as it will be more accurate.

If you can claim otherwise, or show which barrage(s) would compensate for the intermittency of the Seven barrage, please provide evidence. But consider that the evidence that I've seen suggests that this is not the case. You must remember that most tidal schemes have little to offer in terms of installed capacity. The ones I have shown are the ones with the biggest potential outputs.

Basically, the onus is now on you to show otherwise if you think I am wrong.

 

[JohnD]

if you'd care to nominate a time today when you think GB has no tidal energy available, I'll have a go.

 

[wobs]

if you'd care to nominate a time today when you think GB has no tidal energy available, I'll have a go.

You have all the evidence you need to show that there will be little or no output mid tide from a Severn Barrage. But here is another chart:

Showing that mid tide (eg. ~8pm tonight at Cardiff going by the times above), you would have no output from that particular barrage. Given the other barrages would have similar tide times, they would not cancel each other out. Even if they could, the Severn Barrage system would be so big, that other could not compensate for it anyway.

This ignores the inconvenience of placing a barrage far away from where you actually need to connect to the grid.

 

[JohnD]

So you say that at 8pm GB would not have tidal energy available.

What do you mean by mid-tide?

Do you mean half-way between high and low water?

Or do you mean slack water?

The reason I ask that is at 8pm today, Cardiff (as a proxy for a Severn barrage) will be about half-way between high and low water, which is the time when the greatest flow of water occurs.

So I don't understand your assertion that no tidal energy would be available at or near Cardiff.

 

[wobs]

So you say that at 8pm GB would not have tidal energy available.

What do you mean by mid-tide?

Do you mean half-way between high and low water?

Or do you mean slack water?

The reason I ask that is at 8pm today, Cardiff (as a proxy for a Severn barrage) will be about half-way between high and low water, which is the time when the greatest flow of water occurs.

So I don't understand your assertion that no tidal energy would be available at or near Cardiff.

Mid tide as in half way between high and low. I'd of thought the time would have given you a clue from the tide times above.

Here is another chart showing what would happen if you had Severn and five other sites operating, with slightly different tide times:

Again, we see drops in output over each cycle.

 

[JohnD]

The reason I ask that is at 8pm today, Cardiff (as a proxy for a Severn barrage) will be about half-way between high and low water, which is the time when the greatest flow of water occurs.

So I don't understand your assertion that no tidal energy would be available at or near Cardiff.

So please explain your assertion that, at the time of greatest natural flow, there is no tidal power available at the position.

For simplicity, we need only address the question of the (near) Cardiff energy at this time.

 

[wobs]

So please explain your assertion that, at the time of greatest natural flow, there is no tidal power available at the position.

For simplicity, we need only address the question of the (near) Cardiff energy at this time.

Because a barrage works on the height difference of high & low tides, by storing the tidal flow. If it were turbines, the reverse would occur ie. slack tides would give the lowest output. However, given the extremely low potential for turbine installation, these would come no where near to compensating for this pattern.

 

[JohnD]

so your plan is based on the assumption that the gates are opened only at (or near) high water when the lagoon is empty, and low water when it is full.

A plan which is designed to minimise the number of hours during which electricity is generated, and to ensure that it is available only at specific times when it might or might not be needed.

Well, it's certainly one way of getting the graphs to show that tidal is a non-starter. I wonder if that's why it was chosen.

 

[wobs]

so your plan is based on the assumption that the gates are opened only at (or near) high water when the lagoon is empty, and low water when it is full.

A plan which is designed to minimise the number of hours during which electricity is generated, and to ensure that it is available only at specific times when it might or might not be needed.

Well, it's certainly one way of getting the graphs to show that tidal is a non-starter. I wonder if that's why it was chosen.

I've shown multiple sources that show the output pattern.

You have yet to show any evidence . If you disagree with anything I say, show something that demonstrates otherwise.

Of course, this ignores the variations from spring and neap tides, which would also be considerable, albeit over a longer period. But the variations would be multiple GWs.

PS. Its not my plan, but reports from a variety of sources.

 

[JohnD]

I see that although Morecambe is 4.6 hours different from Cardiff, and Southend is 5.9, Southampton is 2.4, Aberdeen is 5.5 and Yarmouth is 4.7. You will be aware that Scotland has numerous sea-lochs, mostly on the West coast, many of them around an hour offset from Cardiff. Yorkshire is about 40 minutes. Judicious choice of sites can easily provide overlaps, given suitable investment.

The gates can be timed to provide energy when it is most needed, and not according to the inconveniently rigid schedule in graphs shown above.

Considering the vast amount of money we intend to pay to the French for constructing an array of atomic kettles, selling us electricity at twice the market rate, I still believe that investment in tidal barrages and lagoons will bring us cheaper energy; and considering how many sites exist in this sceptered isle, I am unconvinced that we can't find a worthwhile amount of capacity.

Sadly the energy lobby is dominated by fossil fuel and nuclear interests. The tidal lobby is probably the least-well-heeled group attempting to influence public opinion.

 

[wobs]

I see that although Morecambe is 4.6 hours different from Cardiff, and Southend is 5.9, Southampton is 2.4, Aberdeen is 5.5 and Yarmouth is 4.7. You will be aware that Scotland has numerous sea-lochs, mostly on the West coast, many of them around an hour offset from Cardiff. Yorkshire is about 40 minutes. Judicious choice of sites can easily provide overlaps, given suitable investment.

The gates can be timed to provide energy when it is most needed, and not according to the inconveniently rigid schedule in graphs shown above.

Considering the vast amount of money we intend to pay to the French for constructing an array of atomic kettles, selling us electricity at twice the market rate, I still believe that investment in tidal barrages and lagoons will bring us cheaper energy; and considering how many sites exist in this sceptered isle, I am unconvinced that we can't find a worthwhile amount of capacity.

Sadly the energy lobby is dominated by fossil fuel and nuclear interests. The tidal lobby is probably the least-well-heeled group attempting to influence public opinion.

Let me reiterate a quote from research earlier regarding barrage systems:
"This potential substantially exceeds that of 'tidal stream' turbine or practicable 'lagoon' systems"
https://www.researchgate.net/publication/245409305_Tidal_energy_potential_in_UK_waters

So your idea that Southampton, Aberdeen, Yarmouth,.... etc could offset this is uninformed. As I have already shown, large scale barrage schemes are the only system that offer significant supply. Other tidal schemes would be small scale in comparison. And the locations of those large scale barrage would not cancel out each other's intermittency, owing to the tide times overlapping (already shown). There are few locations where it is suitable.

Yorkshire - I assume you mean the Humber - has already been addressed.

As for West Coast of Scotland: As I have already pointed out - it has some good locations for tidal turbines, etc. but there are two issues: 1. they are remote and therefore expensive to connect to the grid, and 2. there is little potential for large scale deployment compared to the main barrage schemes.

All of this is before you consider the ecological impact, such as intertidal mudflats, turbines killing marine life, etc. The Wash is home to about 350,000 wading birds in winter, so if they even thought about building one there, there would be up roar.

But all of this doesn't even mention the main reason that the Severn barrage wasn't built: Its a huge capital cost, and the technology isn't transferrable to other sites. In other words, with a nuclear power plant, the more you build of a particular design, the cheaper it gets. But with a barrage, much of it is designed for that location, so its not so transferrable to be copied to other sites, so the cost doesn't get reduced the more you build.

Am against tidal energy? No, as its low carbon technology. But I do recognise its limitations.

 

[JohnD]

We're going to pour vast amounts of money and effort into nuclear, for expensive electricity.

So its valid to say that we could instead pour vast amounts of money and effort into coastal, for cheaper electricity.

And I don't believe that the costs of research into earthmoving are anywhere near the cost of research into building atomic kettles that won't explode (often)

 

[wobs]

Sadly the energy lobby is dominated by fossil fuel and nuclear interests. The tidal lobby is probably the least-well-heeled group attempting to influence public opinion.

You are aware that coal is being phased out aren't you?