Tidal Lagoon - Energy from the Ocean, UK Gov is putting money in it

[Zucca]

IM(very very)HO seems interensting... and reasonable.

I am wondering if you could use it in the Panama or Suez canals.

[tggzzz]

Such schemes only provide intermittent power; it is predictable when they will be generating 10%, 90%, 50%, 10% and 0% of peak power. Hence the capacity of conventional generating plant is unchanged.

Note that generating plant is most reliable when run at a constant power: thermally cycling plant reduces its operating lifetime, sometimes significantly.

BTW. Also look for the Severn Barrage proposals.

[Mechanical Menace]

They've been on about things like this for decades in different parts of the UK, with many a hugely successful trial. Shame it'll never happen, too many NIMBYs will whine about it.


http://en.wikipedia.org/wiki/Pelamis_Wave_Energy_Converter is another approach I think could be more useful, less need to work out how to store the energy for later use.

[Zero999]

Such schemes only provide intermittent power; it is predictable when they will be generating 10%, 90%, 50%, 10% and 0% of peak power. Hence the capacity of conventional generating plant is unchanged.

It's possible to produce power most of the time and it can be stored so it should be able to take some of the load away from conventional generating plants.

[KJDS]

I suspect that it could work well in Scotland, mostly due to the low density of population and plenty of sea lochs that would be easy to put a barrier across. There are far fewer suitable places south of Hadrian's wall.

[Mechanical Menace]

I suspect that it could work well in Scotland, mostly due to the low density of population and plenty of sea lochs that would be easy to put a barrier across. There are far fewer suitable places south of Hadrian's wall.

That's where most of the trials have been run, but like wind farms the locals and landowners don't want their views ruined. Look at where the new wind farms are turning up, on the islands where the companies can give every resident a job to get them to want it, then have underwater power lines bringing the power to the mainland.

The British as a whole are terrible for this stuff. We don't want gas, coal or oil power plants, but we don't want nuclear, wind farms or solar farms or personal wind and solar power (just try to get planning permission) even more than them. FFS if we had fusion working we wouldn't want that either, and you'd have the surviving Hitchens brother whining that fission is safer :/

[tggzzz]

FFS if we had fusion working we wouldn't want that either,

If energy use keeps expanding at the historical rate of 2%/year then, however "green" the source, in 400 years the oceans boil. Simple thermodynamics of black body radiators.

See http://physics.ucsd.edu/do-the-math/2012/04/economist-meets-physicist/

[malch]

Bad idea. It's a scientific fact that it will slow the rotation of the earth!

[coppice]

http://en.wikipedia.org/wiki/Pelamis_Wave_Energy_Converter is another approach I think could be more useful, less need to work out how to store the energy for later use.

Wave power is a very interesting idea, but so far results have been problematic. It has proved difficult to combine, in a single design, the efficient extraction of wave energy and tolerance the worst storms that can occur. Back in the 1970s there were some neat experimental designs which worked well until they were smashed by extreme storms.

[EEVblog]

It's possible to produce power most of the time and it can be stored so it should be able to take some of the load away from conventional generating plants.

That's my understanding as well. It's not just tidal action, but regular wave action which is quite constant in many locations.
We just got a grid connected one online:
http://www.businessinsider.com.au/the-worlds-first-grid-connected-wave-energy-plant-in-western-australia-this-is-how-it-works-2015-2

[tggzzz]

Such schemes only provide intermittent power; it is predictable when they will be generating 10%, 90%, 50%, 10% and 0% of peak power. Hence the capacity of conventional generating plant is unchanged.

It's possible to produce power most of the time and it can be stored so it should be able to take some of the load away from conventional generating plants.

It is possible to produce a small proportion of the power at all times. Unless people will accept lights going off, you need to make up the shortfall from other sources. Hence the capacity of conventional generating plant is unchanged, even if it is used less of the time. Note that conventional plant hates being thermally cycled.

I suggest you do some research to understand the various possibilities for the Severn Barrage, which could produce, IIRC 5% of UK electricity. This has been extensively studied over the past 50 years, and various schemes proposed to offset the variable power output. None are completely successful, and there are significant associated disadvantages. The last time I went to a professional seminar on the Severn and Swansea Barrages, the Swansea Barrage was shown to be comparatively unattractive.

I'm glad you know how to store electricity. I trust you have patented your techniques, because they are worth billion of pounds/dollars etc. Seriously. (If, OTOH, you mean storing energy via water height, then any such advantages/disadvantages will already have been factored in - since that's exactly what the barrage does and doesn't do!)

Separate discussion: whether wind power is intermittent or not (because the "wind is always blowing somewhere"). Unequivocal answer for the UK, both theoretical and measured: wind power is intermittent. About 8% of the time the total UK wind power output is <2.5% of peak. And the UK is one of the best locations for wind power! Have a high pressure zone sat over the UK in winter, and zero wind power lasts for days or weeks. To get spatial diversity, you have to consider areas the size of Europe, and the transmission losses over those distance swould be prohibitive. See http://www.jmt.org/wind-analysis-report.asp for more details.

[tggzzz]

Such schemes only provide intermittent power; it is predictable when they will be generating 10%, 90%, 50%, 10% and 0% of peak power. Hence the capacity of conventional generating plant is unchanged.

Note that generating plant is most reliable when run at a constant power: thermally cycling plant reduces its operating lifetime, sometimes significantly.

BTW. Also look for the Severn Barrage proposals.

They are saying it will have a 120 year lifespan, although presumably the generation parts will be replaced periodically. Also, they can delay the release of water for a few hours if needs be so there is some control over when energy is produced.

First sentence: irrelevant.
Second sentence: simply wrong.

Sorry.

[LabSpokane]

It's possible to produce power most of the time and it can be stored so it should be able to take some of the load away from conventional generating plants.

That's my understanding as well. It's not just tidal action, but regular wave action which is quite constant in many locations.
We just got a grid connected one online:
http://www.businessinsider.com.au/the-worlds-first-grid-connected-wave-energy-plant-in-western-australia-this-is-how-it-works-2015-2

http://www.powerengineeringint.com/articles/2015/03/world-s-first-grid-connected-wave-power-station-activated-in-australia.html

Here's the same system in Power Engineering.  It's a pilot system at 240kW, but at least it's deployed, which is more than most wave energy systems can say for themselves.   Hopefully the pumping mechanism is simple, robust, and will scale well.  They are avoiding the mistake of distributing the electrical generation, which many wave energy systems try to do.   

[Mechanical Menace]

http://www.businessinsider.com.au/the-worlds-first-grid-connected-wave-energy-plant-in-western-australia-this-is-how-it-works-2015-2

http://www.powerengineeringint.com/articles/2015/03/world-s-first-grid-connected-wave-power-station-activated-in-australia.html

Worlds first? Why don't  Pelamis Wave Power's 2004, 2009, and 2010 grid connected tests in the UK, Portugal, and then the UK again count?

[coppice]

Second sentence: simply wrong.

Care to elaborate?

Sorry.

Me too bro. I think you forgot to type in your actual argument. 

You offered no argument. You just made an assertion. Why do expect those replying to work to a higher standard than you?

[tggzzz]

Second sentence: simply wrong.

Care to elaborate?

Context is important, so here it is (again). Please don't snip so much that you distort the points being made.

Such schemes only provide intermittent power; it is predictable when they will be generating 10%, 90%, 50%, 10% and 0% of peak power. Hence the capacity of conventional generating plant is unchanged.
BTW. Also look for the Severn Barrage proposals.

Also, they can delay the release of water for a few hours if needs be so there is some control over when energy is produced.

Firstly you need to explain your mechanism that "delays the release of water for a few hours". Secondly you need to define how your scheme works when the water is the same height on each side of the barrage.

In doing that you should make reference to

• the proposed barrage being a single-basin scheme
  
• the disadvantages of two basin schemes
• the solid physics described in http://www.withouthotair.com/c14/page_81.shtml and http://www.withouthotair.com/cG/page_311.shtml and http://physics.ucsd.edu/do-the-math/2011/12/can-tides-turn-the-tide/
• discussion of Severn barrage and Swansea barrage schemes in http://www.sd-commission.org.uk/data/files/publications/TidalPowerUK1-Tidal_resource_assessment.pdf
• if you refer to Rance,

BTW, calling someone "bro" make you look like a dilettante.

[tggzzz]

Me too bro. I think you forgot to type in your actual argument. 

You offered no argument. You just made an assertion. Why do expect those replying to work to a higher standard than you?
[/quote]

Succinctly and to the point

[rolycat]

The video linked by the OP is a very slick bit of marketing, which generally indicates a need for skepticism.

The project may or may not be technically sound, but it does appear that the unit cost of energy will be very high. The developers are reportedly demanding a strike price of £168/MWh for 35 years under the UK government's Contracts for Difference subsidy scheme. This is around four times the current wholesale price. It is also around twice the cost of onshore wind or PV solar power and will be paid for more than twice as long.

Citizens Advice, a respected UK consumer organization, have described the scheme as a 'boondoggle' offering appalling value for money.

[coppice]

Firstly you need to explain your mechanism that "delays the release of water for a few hours". Secondly you need to define how your scheme works when the water is the same height on each side of the barrage.

Sorry, I assumed you knew how these things work. They have gates that prevent the tide coming in to or out of the lagoon. When there is sufficient differential in the water level on either side of the barrier they open the gates and allow water to run through the turbines, generating electricity. In the normal course of operation this delays tides inside the lagoon a little. The operator can choose to extend or reduce that delay, in which case less than the maximum amount of electricity may be generated but at possibly more useful times.

http://www.bbc.co.uk/news/science-environment-31682529

My apologies, I thought everyone was up to speed.

You are still making the same assertion without backing it up. Can you refute the analysis in the links you were give?

[tggzzz]

You are still making the same assertion without backing it up. Can you refute the analysis in the links you were give?

You mean the bit about what happens when water is at the same level on both sides? In that case there isn't much you can do. I don't really see how that is relevant or contradicts any of what I said though.

It does mean that your comments are irrelevant and/or wrong in the context in which you made them. In particular, such barrages don't reduce the capacity of conventional plant required, and they do require it to be thermally cycled in synchronism with the tides. Not good.

[LordNobady]

we are running one since 2008
http://www.energisingdeltas.com/press-release-proefinstallatie-stromingsenergie-officieel-geopend/
just updated it.

[Zero999]

The water level at both sides is only a problem for one tidal power station.

If several tidal power stations are built in different locations, with slightly different tides there will never be a time when no tidal power station is generating. It is possible for them to take some of the load off conventional power plants.

[coppice]

You are still making the same assertion without backing it up. Can you refute the analysis in the links you were give?

You mean the bit about what happens when water is at the same level on both sides? In that case there isn't much you can do. I don't really see how that is relevant or contradicts any of what I said though.

Is there any possibility that if I keep asking you might eventually answer the question properly?

[tggzzz]

The water level at both sides is only a problem for one tidal power station.

If several tidal power stations are built in different locations, with slightly different tides there will never be a time when no tidal power station is generating. It is possible for them to take some of the load off conventional power plants.

That's a completely different point. The significant operational point is that you can't reduce the required capacity of the conventional plant, even though it will be operated at below capacity for some of the time. The power cycling reduces the plant's lifetime thus making it more expensive.

Your point has some use, but only if you add an extremely limiting caveat. You have to very significantly reduce the total tidal power output - which makes it even more expensive.

[tggzzz]

You seem to be assuming a 1:1 relationship between tidal and conventional power plants, like you have to build a backup coal plant right next to the tidal one or something and use their combined output to produce a perfectly consistent feed in to the grid.

No, I, and others are not.

The grid already deals just fine with a variety of intermittent sources. Coal, gas, nuclear, wind, solar, tidal, none of them are 100% reliable or 100% predictable. The grid doesn't have 200% capacity just to deal with that, and probability doesn't work that way either.

That's a different point, as I hope you are well aware (but I'm beginning to doubt).  We have, infamously, 4%-5% excess capacity. Unexpectedly lose a second major plant, and everybody will notice it.

Let's ask a different very important question. If you rely on a 2GW peak tidal system such as the Severn barrage, what else would you have to ensure the light stay on. To be useful your answer requires numeric capacities and, for intermittent sources such as wind or solar, numeric probabilities of being able to supply the capacity. If relying on wind, please make reference to the measurements detailed in http://www.jmt.org/wind-analysis-report.asp

Hand-waving wishful-thinking will be publicly laughed at.