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

[tom66]

Greenpeace are strongly anti-nuclear. http://www.greenpeace.org/international/en/campaigns/nuclear/

One of the reasons I cannot support them.

They are campaigning for the dismantlement of fossil fuel and nuclear power and replacement of it with:
- Solar, wind, tidal: intermittent
- Geothermal: brilliant but limited
- Biomass: ok if outside of cities and population centres, but limited

[Galenbo]

..., but I'm sure mojo-chan will not address those points but will choose to "answer" points you haven't made.

What did you expect? That guy is payed by the greenscam industry.

They have a scala of 'solutions' that do not work, every time for another reason. When someone points to the reason, they hop to another 'solution'. And again.

[tom66]

I should point out I'm not opposed to renewable energy in any way. I really like the sight of wind turbines; there's one about 2 miles away from my dad's house and I have no opposition to its position (and neither does he!) But, I consider myself a realist on the issue. And the reality is, intermittent power can never form the entirety or even a significant portion of a grid, because it would be too unreliable. Which is why we must invest in good continuous power sources like nuclear and CGGT (with carbon capture) filling in the gap where wind/solar/tides cannot.  Geothermal is great, let's have more of it! But it's really difficult to find places that are amenable to it working at a reasonable price and there is apparently a minor (possibly insignificant) risk of triggering earthquakes when drilling near tectonic boundaries.

[tggzzz]

..., but I'm sure mojo-chan will not address those points but will choose to "answer" points you haven't made.

What did you expect? That guy is payed by the greenscam industry.

While I can understand someone coming to that conclusion, do you have an actual evidence for that assertion?

They have a scala of 'solutions' that do not work, every time for another reason. When someone points to the reason, they hop to another 'solution'. And again.

That is a debating tactic they use, but it does not mean everything green is bad, nor that all points they make are false.

[Someone]

Excuse me, but could you just work through the numbers for us, and show us how you draw that conclusion from the paper you cited?

Page 18, average 5.14% "unplanned" unavailability (something broke).

P(A and B) = P(A?B) = P(A|B)P(B) = P(A)P(B) (if A and B are independent)

Thus around 0.26% of the year there will be two unexpected failures, which is about one day a year. Of course it won't be one full day, it will be multiple times totalling about 24 hours over the course of the year.

That's just for nuclear, and actually the stats are worse in some places where there is more seismic activity or where the reactors are mostly older types. When combined with other fossil fuel plant failures you can see that the grid needs significant amounts of spare capacity to be available instantly to avoid problems. That's why the National Grid likes distributed renewable technologies like wind and solar. Unless transmission lines go down they never suddenly drop a few gigawatts off the network without warning.

So, you don't understand what unplanned downtime means. Fair enough. Maybe you should read more.

Yeah those numbers are bad, what follows is all rounded to a single significant figure and roughly calculated but shows a different story. If we assume a 15min planning interval and a typical scram rate of 1.5% per 7000 hours (from that same reference used) then its a scram rate of 500e-9 per 15 minute interval per reactor.

9 Reactors in the UK, so the chance of any one and only one failing in a 15 minute interval is 5e-6, so a 50% chance of no scrams during a 4 year period.

2 or more failing during a 15 minute interval is 500e-9, for a 50% chance of no loss of 2 or more rectors during a 40 year period.

[Galenbo]

That is a debating tactic they use, but it does not mean everything green is bad, nor that all points they make are false.

I am a big fan of of-the-grid stations that are powered by solar and/or wind. No more long expensive landlines just for that one station.
And converting processes to reversible (replace a loss with creating energy),...

Maybe, in short, with some overgeneralisation, everything that doesn't need tax money.

[Someone]

And the reality is, intermittent power can never form the entirety or even a significant portion of a grid, because it would be too unreliable.

Tidal (pumped or not) and pumped water storages can be a viable solution to the intermittent renewables but at the cost of reducing their sustained capacity. Its all engineering tradeoffs that can be mixed to provide all sorts of solutions, since bulk energy storage is one of the key enabling technologies for the intermittent solar, wave, wind, and water current generators it makes a lot of sense to start investing in large scale water storage if only to see how well it can integrate.

Here are some real world example of the fluctuating markets faced:
http://www.wattclarity.com.au/2007/01/11th-january-2007-first-spike-in-demand-above-30000mw/
Hydro brought on 10% of the total grid load, and was able to balance the ramp up of each of the major peaking plants.

A more recent example of pumped storage profiting:
http://theconversation.com/pumped-hydro-energy-storage-making-better-use-of-wind-18565
Though backed by cheap base load coal power, they can equally soak up peaky renewables.

[tggzzz]

That is a debating tactic they use, but it does not mean everything green is bad, nor that all points they make are false.

I am a big fan of of-the-grid stations that are powered by solar and/or wind. No more long expensive landlines just for that one station.
And converting processes to reversible (replace a loss with creating energy),...

Maybe, in short, with some overgeneralisation, everything that doesn't need tax money.

So you don't have any evidence to support your assertion about his finances, plus you are a neo-con liberal.

You two are indistinguishable and deserve each other

[coppice]

I'm not sure where their dust comes from.

Mainly the Gobi. Think some of it comes from the former USSR.

So there's no actual fog involved in Chinese/Indian smogs, just dust and pollution? Strange use of the word lol.

People usually say its the Gobi, but I think its more complex. Northern China has large areas with very fine powdery soil, which has been deeply eroding since the dawn of agriculture. In the dry parts of the year I think this is the source of a lot of the dust plaguing Beijing.

Many cities in China used to have serious problems of dust in the air, due to the extreme amounts of construction work going on. These days some cities, like ShenZhen, have matured a lot, and construction rates have slowed. All cities are now subject to environmental control laws, which enforce the use of dust nets over large construction sites. People might try to evade some environmental laws, but if you are building towers without nets it stands out like a sore thumb. Hence, this is a one environmental law which is pretty strictly enforced.

[coppice]

And the reality is, intermittent power can never form the entirety or even a significant portion of a grid, because it would be too unreliable.

Tidal (pumped or not) and pumped water storages can be a viable solution to the intermittent renewables but at the cost of reducing their sustained capacity.

Tidal power can never be a major source of power, so its intermittent nature is not an inherent constraint to its use. Tidal might be a useful part of a total mix of energy sources, in certain specific places, but the planet's total tidal power is not sufficient to meet human needs.

Tidal works in places like the Severn in the UK. The global tides are less than one metre, varying with the relative positions of the sun and moon. They are largely predictable, which is a really good quality for an energy source. Its wrong to say tidal is unreliable. You know when its going to be available years in advance, and you know the approximate amount of energy you are going to get. Its just intermittent. The big snag is the energy is spread over vast distances, and the water head is small. Take a place like the west coast of the UK or France, and tides are magnified by the continental shelf. Add the effects of funnelling the water into spots like the Severn, and tides can be 8m to 10m high. Now you have the kind of concentration of power which can make it useful. Its a resonant effect, though. If you want to extract energy from a resonant system, you need to work in sympathy with it. Fight it, and the energy dissipates. This is why talk of time shifting is a non starter. You can nudge the timing by a small amount, but if you try to move significantly away from the optimal timing, the total available energy rapidly drops. Some people have written as though the goal is to get a dribble of energy 24 hours a day. If you aren't getting a lot of energy you could never justify the resources needed for construction. You probably wouldn't even have a net energy benefit, after you amortise the construction energy consumption over the system's working life. Any required barrage should have a long life, but the expensive equipment won't. Mechanics doesn't life variable operation. Just compare the few thousand hour life of a diesel engine in a vehicle, with the 25 year life a diesel engine in steady 24 hour use can offer with reasonable overhaul cycles.

[tggzzz]

Its a resonant effect, though. If you want to extract energy from a resonant system, you need to work in sympathy with it. Fight it, and the energy dissipates. This is why talk of time shifting is a non starter.

Oh, that's an interesting analysis!

While the general populace might not understand it, people on this forum ought to.

[tggzzz]

So, I don't think your characterization of them [Greenpeace] as "environmentalists" is fair. They are at the far end of what is possible, but they have a clear, well thought out plan and so far no-one has demonstrated that it wouldn't work. The issue, as they acknowledge, is political will, not technical.

Some of their tatics and arguments are indeed mental, and their supporters tend to be well-meaning idiots. Other organisations within the green movement are far less disreputable.

I remember visiting a Greenpeace exhibition in which they attempted to demonstrate that radioactivity was nasty. The technique they chose was to have a container covered so that you couldn't see what was in it. When you put your hand in it you found something slimy, and naturally went "yuck". Their acolyte then told you that radioactivity was just as yucky.

That's idiotic disreputable scaremongering, nothing less.

[dannyf]

no-one has demonstrated that it wouldn't work.

The fact that you failed to comprehend the demonstration doesn't mean the demonstration has failed to be understood by others.

[SeanB]

Simple way is to install smart metering for the greens, and tie their supply to the output from any renewable resources they choose, then only connect them to the grid when said supply is actually generating power into the grid, switching on meters as the power increases to keep them from ever having to use "dirty "power. That way they get wholly green power whenever it is available. Contract is unalterable for the economic life of the generating plant of course. When the source fails they get to pay for the restoration of the area to as it was before of course. Then they can pay for the new plant that replaces it.

I think that will be a good idea.

[coppice]

Here is an interesting report by the California government: http://www.cpuc.ca.gov/NR/rdonlyres/8A822C08-A56C-4674-A5D2-099E48B41160/0/LDPVPotentialReportMarch2012.pdf

Long story short even the US grid could hit 100% solar PV capacity and cope with the intermittent nature of it without major problems. It's just a shame that Germany and/or Scotland will be the ones to prove it with a working system first, with little real competition.

That report does not even consider anything approaching 100% solar PV for California. It only looks at options to generate up to 16.5GW by solar PV, which it says is 30% of peak demand. It  clearly explains why going higher than 30% would cause serious network problems, unless issues that current systems do not address are handled properly. That puts the peak demand at about 55GW, although I found other figures which put California's peak at over 60GW. They do not consider storage, so there is no provision for using stored solar PV energy during darkness. If solar contributes 30% during the highest output part of the day in summer, I wonder what its percentage of the total annual generated energy would be? Quite significant, sure, but not even in the ballpark of 100%.

[mtdoc]

Physicist Tom Murphy has done an analysis of the issues of abundance and intermittency for all of the possible sources of electricity generation. He did an excellent series of blog posts on the topic.  A nice summary post can be found HERE.  Here's a nice summary table:

[dannyf]

That report does not even consider anything approaching 100% solar PV for California.

What the report actually says doesn't matter.

What matters is what mojo-chan says it says.

Essentially, the report says whatever mojo-chan says it says, even if it doesn't say that or it says the opposite.

[Someone]

And the reality is, intermittent power can never form the entirety or even a significant portion of a grid, because it would be too unreliable.

Tidal (pumped or not) and pumped water storages can be a viable solution to the intermittent renewables but at the cost of reducing their sustained capacity.

Tidal power can never be a major source of power, so its intermittent nature is not an inherent constraint to its use. Tidal might be a useful part of a total mix of energy sources, in certain specific places, but the planet's total tidal power is not sufficient to meet human needs.

Tidal works in places like the Severn in the UK. The global tides are less than one metre, varying with the relative positions of the sun and moon. They are largely predictable, which is a really good quality for an energy source. Its wrong to say tidal is unreliable. You know when its going to be available years in advance, and you know the approximate amount of energy you are going to get. Its just intermittent. The big snag is the energy is spread over vast distances, and the water head is small. Take a place like the west coast of the UK or France, and tides are magnified by the continental shelf. Add the effects of funnelling the water into spots like the Severn, and tides can be 8m to 10m high. Now you have the kind of concentration of power which can make it useful. Its a resonant effect, though. If you want to extract energy from a resonant system, you need to work in sympathy with it. Fight it, and the energy dissipates. This is why talk of time shifting is a non starter. You can nudge the timing by a small amount, but if you try to move significantly away from the optimal timing, the total available energy rapidly drops. Some people have written as though the goal is to get a dribble of energy 24 hours a day. If you aren't getting a lot of energy you could never justify the resources needed for construction. You probably wouldn't even have a net energy benefit, after you amortise the construction energy consumption over the system's working life. Any required barrage should have a long life, but the expensive equipment won't. Mechanics doesn't life variable operation. Just compare the few thousand hour life of a diesel engine in a vehicle, with the 25 year life a diesel engine in steady 24 hour use can offer with reasonable overhaul cycles.

Take the whole quote in context

And the reality is, intermittent power can never form the entirety or even a significant portion of a grid, because it would be too unreliable.

Tidal (pumped or not) and pumped water storages can be a viable solution to the intermittent renewables but at the cost of reducing their sustained capacity. Its all engineering tradeoffs that can be mixed to provide all sorts of solutions, since bulk energy storage is one of the key enabling technologies for the intermittent solar, wave, wind, and water current generators it makes a lot of sense to start investing in large scale water storage if only to see how well it can integrate.

Here are some real world example of the fluctuating markets faced:
http://www.wattclarity.com.au/2007/01/11th-january-2007-first-spike-in-demand-above-30000mw/
Hydro brought on 10% of the total grid load, and was able to balance the ramp up of each of the major peaking plants.

A more recent example of pumped storage profiting:
http://theconversation.com/pumped-hydro-energy-storage-making-better-use-of-wind-18565
Though backed by cheap base load coal power, they can equally soak up peaky renewables.

Using the tidal and pumped water generators for storage a 100% renewable grid is plausible, even with the solar/wind/wave power being unreliable because you can store sufficient energy in the tidal (short term storage to match solar output for instance) and pumped storages to ride out the lulls in production from other sources. Its already done here in Australia on a substantial scale with the mountain based hydro.

[tggzzz]

Using the tidal and pumped water generators for storage a 100% renewable grid is plausible, even with the solar/wind/wave power being unreliable because you can store sufficient energy in the tidal (short term storage to match solar output for instance) and pumped storages to ride out the lulls in production from other sources. Its already done here in Australia on a substantial scale with the mountain based hydro.

In Australia maybe. The UK is much more crowded and additional pumped storage options are significantly limited by terrain.

[Someone]

Using the tidal and pumped water generators for storage a 100% renewable grid is plausible, even with the solar/wind/wave power being unreliable because you can store sufficient energy in the tidal (short term storage to match solar output for instance) and pumped storages to ride out the lulls in production from other sources. Its already done here in Australia on a substantial scale with the mountain based hydro.

In Australia maybe. The UK is much more crowded and additional pumped storage options are significantly limited by terrain.

Its all trade offs, current population levels and lifestyles are probably not sustainable. All options require some sort of impact but its simply easiest (politically and short term economically) to stick with the status quo. Your claim that tidal power cannot be a major source of power is incorrect, it may not be able to be able to harvest a large percentage of the energy supply but as a demand driven supply it can deliver huge amounts of power when its needed.

[tggzzz]

Your claim that tidal power cannot be a major source of power is incorrect,

I have never claimed that.

it may not be able to be able to harvest a large percentage of the energy supply but as a demand driven supply it can deliver huge amounts of power when its needed.

It can intermittently deliver huge amounts of power at some times, which may or may not be when it is needed.

[Someone]

Your claim that tidal power cannot be a major source of power is incorrect,

I have never claimed that.

it may not be able to be able to harvest a large percentage of the energy supply but as a demand driven supply it can deliver huge amounts of power when its needed.

It can intermittently deliver huge amounts of power at some times, which may or may not be when it is needed.

When managed as a storage resource it can deliver power when it is needed, trading off against the energy capability that it could achieve were storage not required. That it can't be a primary source of power is in disagreement with the conservative estimates for the UK in "Sustainable Energy - without the hot air"
http://www.withouthotair.com

[coppice]

Using the tidal and pumped water generators for storage a 100% renewable grid is plausible, even with the solar/wind/wave power being unreliable because you can store sufficient energy in the tidal (short term storage to match solar output for instance) and pumped storages to ride out the lulls in production from other sources. Its already done here in Australia on a substantial scale with the mountain based hydro.

Don't conflate pumped storage with tidal power. We know all about pumped storage, as it has a long track record. If you have the right geographical features in sufficient quantity it is the only proven high capacity storage system around. If you could economically construct sufficiently big lakes you could even ride over the kind of huge lulls in output which wind farms give you. Few places have the necessary geography, though.

Tidal is very different. It has value, although limited value, as an energy source. Tidal is very unsuitable as a storage scheme. As I said, its a resonant effect and you have to go with the flow, or lose most of its capacity.

[Someone]

Using the tidal and pumped water generators for storage a 100% renewable grid is plausible, even with the solar/wind/wave power being unreliable because you can store sufficient energy in the tidal (short term storage to match solar output for instance) and pumped storages to ride out the lulls in production from other sources. Its already done here in Australia on a substantial scale with the mountain based hydro.

Don't conflate pumped storage with tidal power. We know all about pumped storage, as it has a long track record. If you have the right geographical features in sufficient quantity it is the only proven high capacity storage system around. If you could economically construct sufficiently big lakes you could even ride over the kind of huge lulls in output which wind farms give you. Few places have the necessary geography, though.

Tidal is very different. It has value, although limited value, as an energy source. Tidal is very unsuitable as a storage scheme. As I said, its a resonant effect and you have to go with the flow, or lose most of its capacity.

Tidal can be looked at as a pumped storage with a trivially small head, and yes as I keep pushing its a trade between storage capacity and energy production. As per the post above there is a huge untapped potential in both and is not constrained by a lack of suitable places to build (local nimby outrage is a problem with any large development).

[dannyf]

If you could economically construct sufficiently big lakes you could even ride over the kind of huge lulls in output which wind farms give you.

Think about those water storage facilities and how your enemies could use them against you in a time of war.