[Mootle (OP)]

"I thought we had got to the bottom of the 'laws of physics' - are you still questioning my claims?"
There are two ways your idea could be made to work.
Make it vastly cheaper or get much more energy from it.
I was covering both bases.

OK, we have established that the laws of thermodynamics haven't been violated.

I agree with your summation. The initial line of development will be put the pontoon to work by combining, wind, solar & hydro to greatly increase the energy mix and yield. Zero fossil fuel, Hydrogen and fresh water production is also an option. Either way the engineering would be geared to give a desirable RoI before being presented to prospective investors.

[Mootle (OP)]

EDIT2: I wonder how this stacks up against wind power? I do know that the economics of wind power are (to put it politely) a wee bit dodgy, and the aesthetic impact of wind power can be really horrible. The last time I was in Scotland, I was pretty disgusted by the desecration I observed. 

I don't think you would get a meaningful patent for your idea as it touches on other ideas which are already out there and even if it didn't you would have scuppered it by posting it on an public forum. As per the PM I sent to you, I think it would be a really useful service to offer a private forum where inventors could seek guidance / help with patenting / modelling and presentation from forum members. This would involve nondisclosure contracts being agreed between inventors and contributors. Once priority was in place the idea could then be discussed in an open forum to help refine the idea.

It's not a good idea to publically post any idea without first securing priority with a patent application.

Wind power is a multibillion pound industry. One of the reasons for this is that current legislation guarantees that investors get a good RoI over time. Large, offshore wind projects generate a lot of energy over time and will form an integral part of any renewable energy mix for a island such as the UK.

Hydropower tends to be used as a top up for peak periods of demand owing to the storage element. As the energy mix moves toward renewables the renewable mix reliability will become more important.

[Bored chemist]

"In summary and disregarding areas of speculation the response was that the principle is sound and that the claimed energy balance and."
I don't agree that the " potential revenue stream is theoretically possible".
The revenue is small.
Whatever you make the structure from it will need to be maintained and repaired.
I think that the ongoing costs will exceed the revenue.
The only way it could conceivably work would be if we voted in a government who really wanted to waste money backing this scheme in spite of the fact that it will never produce as good a rate of return (KWH/£) as, for example, a wind turbine.
To get this to work you need to go into politics in a big way.

[Bored chemist]

"You seem to be confusing revenue with cost."
No, since I said "costs will exceed the revenue" there's no way I could have thought they were the same thing.

The difference is clear to me. One is money coming in and the other is money going out.
To be a success, the money coming in has to exceed the money going out.
I don't think your system will or can ever achieve that.

[Mootle (OP)]

I don't agree that the " potential revenue stream is theoretically possible".

You say that but from your previous post the above quote is flawed. Once the energy generation potential is agreed, the stated revenue is also deemed to be agreed since the revenue is calculated directly from the energy that is generated.

As to the cost, at this point in time I would agree that your 'guess' is as good as mine. However, when writing business cases I prefer to work it out. If the answer turns out per your speculation I will be the first to admit that the idea doesn't hold water but for now I simply do not have an answer to that question as the design development has not taken place.

ps. I deleted my earlier post as I modified that by mistake rather than quoting yours.

[Geezer]

I don't think you would get a meaningful patent for your idea as it touches on .........

Actually, I'm not interested in obtaining a patent for something like this. I was really only interested in seeing if it's possible to come up with something that might have a snowball's chance of actually working. The fact that there is something similar to this already wouldn't surprise me, because this is one of the few ways it's actually going to work. If there is anything novel about this idea (which I doubt), I'm quite happy that I've prevented anyone else from patenting it.

There is little point in obtaining a patent on an alternative method of doing something that offers no advantages over an existing method. Also, "kitchen sink" patents that attempt to combine all sorts of existing techniques are pretty much worthless because it's too easy to bypass their claims, whereas some of the best patents are those that overcome a problem that the prior art has failed to deal with.

[Geezer]

I took a shot at an economy version.

 [ Invalid Attachment ]

This might help to address BC's concern that you need a big strong floaty thing, though it does still need to be big and floaty.

The hydraulic ram is now submerged and attached to the float and the anchor by cables or chains. The big floaty thing is full of air under enough pressure to prevent it collapsing at that depth. Not shown in much detail (cos I was too lazy to draw it) is a net-like thing that surrounds the spherical float and spreads the load from the ram over its upper surface. Maybe that's made of Kevlar, or carbon fibre?

Exactly what the float is made of is a bit of a mystery. I suspect it could be from any number of things. The important thing is that the air must not be able to leak out quickly, although a small amount of leakage could be tolerated and made up from a supply of compressed air.

Obviously the ram should be enclosed to keep seawater away from it, particularly the rod.

Interestingly, the control system is remarkably simple. All it has to do is keep the hydraulic pressure in the ram at a minimum pressure. If the tide is rising, the pressure tends to rise, so the system sends fluid to the hydraulic motor to relieve the pressure. When the tide if falling, the system pumps fluid into the ram to maintain the minimum pressure. That ensures the float maintains a constant level relative to the water surface.
 

[Bored chemist]

Mootle,
The biggest (by far) uncertainty in the revenue is some theoretical subsidy that a government might pay.
You seem to think the revenue stream is adequate.
I don't.
The numbers (uncertain though they are) are on my side.
It wasn't going to make money, even with a stupidly large subsidy.

[Mootle (OP)]

Mootle,
The biggest (by far) uncertainty in the revenue is some theoretical subsidy that a government might pay.
You seem to think the revenue stream is adequate.
I don't.
The numbers (uncertain though they are) are on my side.
It wasn't going to make money, even with a stupidly large subsidy.

What ever you think, the government incentives are extant - if you are a citizen of the UK you're already paying for the policy to which Tony Blair committed the UK to many years ago. Energy suppliers are required to include a mix of renewables as part of their portfolio in order to retain their licence to operate.

It is absurd to assert that the numbers fall on either side. Math doesn't subscribe to favouritism, the numbers will be what they are, when the time comes - further dialogue in this regard is futile.

[Bored chemist]

"What ever you think, the government incentives are extant - if you are a citizen of the UK you're already paying for the policy to which Tony Blair committed the UK to many years ago."
I'm a UK citizen. I'm aware of the analogous subsidy for some forms of renewable energy.
I'm also aware that the original planned subsidy is due to come to an end.
The current government is not enthusiastic about spending money (in general) so I wouldn't like to build a business case on the current subsidy.

On one side we have a cost measured inn tens or hundreds of millions. On the other we have a reliable revenue measured in hundreds of thousands per year.
The numbers on one side really are bigger than those on the other.
The side of the argument they favour is clearly the side that says "This is silly and will never work in a month of Sundays".
As far as I can tell, that's my side, not yours.

I know the suppliers are required to use renewables.
But they are not stupid.
I can go into town and pay £150 for a 50W wind turbine. so, with no economies of scale or government subsidy I can get power for £3 per W.
http://www.maplin.co.uk/50w-telescopic-vertical-axis-wind-turbine-396269
Your system produced something like 0.8MW ( ignoring efficiencies)
I could get that from 16000 similar wind turbines (it would be a stupid way to do it, but I could). That would cost me £2.4M
Or I could spend something like 10 or 100 times more on untested technology.
How stupid would I have to be to do that?

[Mootle (OP)]

"What ever you think, the government incentives are extant - if you are a citizen of the UK you're already paying for the policy to which Tony Blair committed the UK to many years ago."
I'm a UK citizen. I'm aware of the analogous subsidy for some forms of renewable energy.
I'm also aware that the original planned subsidy is due to come to an end.
The current government is not enthusiastic about spending money (in general) so I wouldn't like to build a business case on the current subsidy.

On one side we have a cost measured inn tens or hundreds of millions. On the other we have a reliable revenue measured in hundreds of thousands per year.
The numbers on one side really are bigger than those on the other.
The side of the argument they favour is clearly the side that says "This is silly and will never work in a month of Sundays".
As far as I can tell, that's my side, not yours.

I know the suppliers are required to use renewables.
But they are not stupid.
I can go into town and pay £150 for a 50W wind turbine. so, with no economies of scale or government subsidy I can get power for £3 per W.
http://www.maplin.co.uk/50w-telescopic-vertical-axis-wind-turbine-396269
Your system produced something like 0.8MW ( ignoring efficiencies)
I could get that from 16000 similar wind turbines (it would be a stupid way to do it, but I could). That would cost me £2.4M
Or I could spend something like 10 or 100 times more on untested technology.
How stupid would I have to be to do that?

More speculation, a sizable chunk of nonesense and another serving of sarcasm but the fact remains that only time will tell.

[Bored chemist]

The power generation rates are not speculative.
The price of the wind turbines are not speculative.
The only speculation and nonsense are your strange idea that your system will somehow become vastly cheaper than it is.
Time has, for all practical purposes, already told.
You (almost certainly) can't make one vital component of your system for the money it would cost to set up a known system.

[Geezer]

I was quite encouraged by the "economy version", so I thought it might actually be useful in remote locations if it wasn't too expensive. I started with the assumption that I wanted to power a single 13A 230V outlet on Muckle Flugga - not continuously mind you - only while the tide was coming in at its maximum rate.

Assumptions:
The tide is rising at 0.15 mm/s.
Overall conversion efficiency to electricity is 60%

So,
Work is being done by rising tide at 4.6kJ/s
Force on ram is 4600/0.00015 = 30MN
Displacement of float is 30/10 = 3 Mega kg or 3000 tonnes.

The large floaty thing still needs to displace the equivalent of 1.5 million two litre soda bottles, and the anchor better weigh about 6000 tonnes.

Unless I mucked something up here (which is highly possible) this scheme is Le canard mort.

[Bored chemist]

You might get an Arts Council grant to cover the cost.

[Mootle (OP)]

The power generation rates are not speculative.

What seasonal efficiency do you think your turbine will achieve. A quick google of micro wind turbines will tell you that your own gut feeling for making such a comparison was indeed 'stupid'.

The price of the wind turbines are not speculative.

What do you think the installed cost of your turbine would be?

The only speculation and nonsense are your strange idea that your system will somehow become vastly cheaper than it is.

I haven't developed the design as yet, let alone costed it so how can it become vastly cheaper. I've set out why the the reused value of 7 large tankers is not a useful representation of the cost of the pontoon. Do you honestly think that repeating the same argument changes anything?

Time has, for all practical purposes, already told.
You (almost certainly) can't make one vital component of your system for the money it would cost to set
up a known system.

Only time will tell what shape the system design takes and thereafter the cost.

Only time will tell what revenue can be achieved by adopting a power mix.

Only time will tell what changes are made to the extant government incentive schemes.

You refusal to accept these basic premises are baffling.

[Mootle (OP)]

I was quite encouraged by the "economy version", so I thought it might actually be useful in remote locations if it wasn't too expensive. I started with the assumption that I wanted to power a single 13A 230V outlet on Muckle Flugga - not continuously mind you - only while the tide was coming in at its maximum rate.

Assumptions:
The tide is rising at 0.15 mm/s.
Overall conversion efficiency to electricity is 60%

So,
Work is being done by rising tide at 4.6kJ/s
Force on ram is 4600/0.00015 = 30MN
Displacement of float is 30/10 = 3 Mega kg or 3000 tonnes.

The large floaty thing still needs to displace the equivalent of 1.5 million two litre soda bottles, and the anchor better weigh about 6000 tonnes.

Unless I mucked something up here (which is highly possible) this scheme is Le canard mort.

Your system wasn't fully defined so I've run a rough order calculation for a continuous 3kW demand.

For this purpose we would need (2) buoyancy engines.

Each system would require storage for 12hrs and a flow rate of ca. 0.0071m3/s.

A generator inlet CSA of 0.017m2 would give the flow rate based on a working head of 50m assuming an 85% turbine / generator efficiency.

Thus, the required Storage Vessel volume would be ca. 300m3, say a cylindrical tank ca. 10m diam * 4m.

Based on a 25:1 gearing ratio each Pontoon volume would be ca. 7,500m3, say equivalent to a rectangular tank ca. 65 * 20 * 6m.

Generation phases would be offset assuming a typical (2) tide per day cycle. Based on this arrangement the Pontoon loading would not occur simultaneously. Therefore, there is scope to engineer an arrangement such that both Storage Vessels operate from one Pontoon, which carries a number of operational and financial advantages.

Tidal range is assumed as 2m.

I don't plan to use a traditional anchor. 

This system is not optimised for revenue recovery but rather to meet a continuous demand in the absence of any energy mix.

No allowance has been made for gross volume.

If a continuous power supply isn't required I expect an hybrid solar PV / wind system would be a more cost effective solution for this particular application.

However, if it's important that your pc and lights continue to operate during the night time you might want to consider the Buoyancy Engine.

[Bored chemist]

"What seasonal efficiency do you think your turbine will achieve. A quick google of micro wind turbines will tell you that your own gut feeling for making such a comparison was indeed 'stupid'."
Yes, But I did it on purpose.
I deliberately chose a ridiculous system and I ignored obvious  factors like the fact that you wouldn't use such small generators and also that you would qualify for a bulk discount. I also ignored the fact that these things only run when the wind blows. Of course, the importance of that depends on where you put them. Where I live the mean wind speed isn't high enough to turn that generator.

However, in spite of all that - which as you say makes them stupid.
The purchase cost is still less than your idea. Not marginally less, not a bit less, but a whole lot less. Something like £2.4M rather than tens or hundreds of millions. You keep saying that time will tell what the true cost will be. Fair enough, but can you (as I have asked before) come up with some explanation of why you feel that you will be able to make this cheaper than, for example, a scarp supertanker?


Incidentally, you say
"I don't plan to use a traditional anchor. "
presumably that means you plan to use something more expensive or you think that the professionals have been getting it wrong all this time.

Your idea that the government will suddenly decide to fund your dead duck rather than, for example this live one is the baffling thing
http://en.wikipedia.org/wiki/Salter's_duck

The government thinks renewable power is a good thing. So do I, but that's not the point.
So they will fund schemes to generate it.
But they won't fund any old scheme. They schemes have to compete against each other.
Since there's no way that you can build yours for less than roughly 10 times the cost of a bunch of stupidly inefficient ones which deliver the same power, there's no incentive for them to fund it.
You will always make a loss on this.

[Geezer]

Your system wasn't fully defined so I've run a rough order calculation for a continuous 3kW demand.

I encourage you to scrutinize my numbers very carefully. Either I mucked them up, or you are stiffing yourself by making the pontoons twice as large as they need to be.

As I mentioned a couple of times already, and as any engineer worth their salt will point out, it's generally a really good idea to figure out how much energy is actually going into a system so that we can compare and contrast it with the amount of energy that is coming out of the system. When we figure it all out, net energy should be pretty close to zero.

[Geezer]

You might get an Arts Council grant to cover the cost.

Strangely enough, I did consider that possibility.

My application to the Arts Council includes a twenty meter bust of Julius Geezer made from crushed beer cans that sits atop the big floaty thing. The residents of Muckle Flugga are bound to appreciate it.

I have named my artistic endeavour "Roman in the Gloamin"

[Mootle (OP)]

"What seasonal efficiency do you think your turbine will achieve. A quick google of micro wind turbines will tell you that your own gut feeling for making such a comparison was indeed 'stupid'."
Yes, But I did it on purpose.
I deliberately chose a ridiculous system and I ignored obvious  factors like the fact that you wouldn't use such small generators and also that you would qualify for a bulk discount. I also ignored the fact that these things only run when the wind blows. Of course, the importance of that depends on where you put them. Where I live the mean wind speed isn't high enough to turn that generator.

However, in spite of all that - which as you say makes them stupid.
The purchase cost is still less than your idea. Not marginally less, not a bit less, but a whole lot less. Something like £2.4M rather than tens or hundreds of millions. You keep saying that time will tell what the true cost will be. Fair enough, but can you (as I have asked before) come up with some explanation of why you feel that you will be able to make this cheaper than, for example, a scarp supertanker?


Incidentally, you say
"I don't plan to use a traditional anchor. "
presumably that means you plan to use something more expensive or you think that the professionals have been getting it wrong all this time.

Your idea that the government will suddenly decide to fund your dead duck rather than, for example this live one is the baffling thing
http://en.wikipedia.org/wiki/Salter's_duck

The government thinks renewable power is a good thing. So do I, but that's not the point.
So they will fund schemes to generate it.
But they won't fund any old scheme. They schemes have to compete against each other.
Since there's no way that you can build yours for less than roughly 10 times the cost of a bunch of stupidly inefficient ones which deliver the same power, there's no incentive for them to fund it.
You will always make a loss on this.

You really don't get this at all. Whilst it is interesting to get 'points of view' it does get a little tiresome going over the same points. Suffice to say I will use meaningful data for the business case rather than ill informed guess work. I don't see that this should be such an affront to your sensibilities, after all I've made no claims as to the system costs to date.

Despite, what you think this is a new idea so anchorage for such a development would need an innovative approach. Typically, the loading is compressive rather than tensile and the forces involved will be huge. As I indicated previously, I will show the principles on a construction animation once I get around to it. My objective is to attain healthy savings against traditional marine anchorage methods whilst improving the sustainability of such a scheme.