Future Energy Sources 1.3.1 Tidal Power

Hi Masu, you wrote: "So is it worth pursuing and is the millisecond we would need to add to the length of the day every decade or so acceptable?"

As physicist and myself debated on a previous thread, the extraction of energy form the tides may in some cases actually work against the normal tidal slow-down of the rotation! It is due to dampening effects of the turbines in estuarial flows.

In any case, if I recall correctly,the Moon robs us of much more rotational energy than what you calculated above. So, if it becomes practical, let's use it!

Regards, Jorrie

Hi Jorrie,

Either way the effect is miniscule and I believe many thousands of times less than our current practice of burning fossil fuels so I must agree that wherever it is feasible then using it is a good idea.

At any rate the absolute worst that could happen is that we would need to adjust the calendar slightly by either adding or subtracting a leap year every few millennium. It would definitely be less of a hassle than fixing the Y2K bugs that just about every computer program on earth had.

Actually I just had a thought about the effect of rising sea levels. A quick analysis would suggest that the redistribution of the mass from at or near the poles would slow the earths rotation. Standard conservation of momentum concept.

I wonder, would a one meter rise in sea level lengthen a day appreciably?

Hi masu, you asked, "I wonder, would a one meter rise in sea level lengthen a day appreciably?"

I would think so, yes. A very rough calc gives it as about 1 in 10⁷, meaning ~10 ms per day or ~3 sec per annum.

Regards, Jorrie

That's several orders of magnitude greater than the effect that tidal power could have and while we mightn't notice it directly there would be a detectable effect on things like astronomy and celestial navigation.

Bugger it, just when I thought I had the alignment of the computerized tracking unit on my telescope spot on global warming is going to stuff it all up again. I wonder if I they will offer a software upgrade to allow for the longer day?

So if I read through your answer: the moon drags the water around and this is stopping the earth to turn. Sun is also playing with the water, how does this effect earth rotation?

What would be the effect of us trying to harvest this energy? would it have influence on the earth rotation? I would suggest that the earth's rotation slow down would go slower as we convert a part of the energy, that is now consumed by sea-earth friction, into electricity.

Is there something wrong with the calculation? I would think that every politician can have the same results on his desk and kill the next power plant investment.

The energy in the currents through the channel, street of Gibraltar, Golden Gate,... could easily supply energy for the whole regions.

Combine it with the other systems and large networks to cope with downtimes.

Reducing the energy in waves would not be bad for coastal erosion - placing the units near the base of cliffs could reduce the amount of material being worn away. Even oustide the dams in Netherlands.

Hi Gwen, you asked: "... the moon drags the water around and this is stopping the earth to turn. Sun is also playing with the water, how does this effect earth rotation?"

In fact, the "dragging" of the water is a minor effect - it's the bulge in the crust of Earth caused by the Moon-Sun combination that does most of the slowdown. It takes enormous energy to cause a bulge of a few cm and that comes off Earth's rotational energy. I have a feeling that currents under the crust, in the magma, might be another contributing factor.

Tidal power generation will have no noticeable influence on the Earth's rotation, of that I'm confident. It may have environmental impacts though, some negative and some positive, as a previous poster pointed out.

Regards, Jorrie

I've never been able to find out where the energy that created the rotational momentum and orbital momentum came from in the first place or if there is something in the universe that either enhances it of detracts from it apart from known friction effects. I've learnt over the years that it isn't wise to meddle with things you don't understand so we need to record and research thoroughly as each installation comes on line if we want to use this energy source. At least the effects should be easily measurable and reasonable self explanatory.

Waves on the other hand should be largely fair game, with careful measurement to be sure, to be sure.

Hi Emjay4119,

I've never been able to find out where the energy that created the rotational momentum and orbital momentum came from in the first place or if there is something in the universe that either enhances it of detracts from it apart from known friction effects.

Primarily the rotational energy comes from gravity and the conservation of momentum. As a star condenses out of a cloud of dust any motion of the dust that is not directly towards the center of the condensing cloud will result in the rotation of the cloud. It is this rotation of the condensing disk that gives the planets their orbital energy

The same thing happens as each of the planets condenses out of the rotating mass that is forming the star-planetary system. This more isolated rotation is what gives the planets their rotational energy.

For a system to be able to condense and form a star without imparting any rotation the cloud of dust would need to be completely symmetrical, homogeneous and perfectly stationary. Any asymmetry, variation in density or initial velocity would cause the system to rotate and like an ice skater that brings their arms in, the collapse of the cloud and conservation of momentum will steadily increase in rotational speed.

Since in reality it would be impossible to achieve a perfectly symmetrical homogeneous and stationary cloud just about everything in the universe has some sort of rotational energy.

I've learnt over the years that it isn't wise to meddle with things you don't understand so we need to record and research thoroughly as each installation comes on line if we want to use this energy source. At least the effects should be easily measurable and reasonable self explanatory.

The concept of a rotating body is well understood and we can and have, in this thread, calculate the effect that using the Earths rotational energy to power civilization would be. The calculations showed that the effect would be miniscule and be many orders of magnitude less than the effect rising sea levels will have. In reality by reducing the rise in sea level we would more than likely reduce the overall impact on the earths rotation.

Hi Jorrie,

why is continental crust deformation requiring more energy than driving a tidal waves around the earth?

Crust shall consist mostly of highly elastic low damping material.

But pulling water up and let it down again? do you have any estimate of the damping?

I did a calculation of the additional acceleration: two parts, one is attraction by the moon the other is centrifugal acceleration by rotaion of the moon-earth system around a point 1/4 earth radius below the surface of earth at the side nearest to the moon.

This is giving 39 resp 33 times 10^-6m/s² the higher value at the side to the moon.

Gravity is decreasing with elevation? This cannot be the deciding factor as yielding much too high tides. So what is determining how high will be the high and low tide.

Regards

RHABE

Hi RHABE, you asked: "why is continental crust deformation requiring more energy than driving a tidal waves around the earth?"

Consider flattening the Earth at two axes by ~0.5 meter and stretching it in the third axis by ~0.5 meter - that takes some energy! Remember that the crust, with ocean and all is lifting that ~0.25m on each side, so this is not causing coastal tides - the water lifts as much as the land. It is rotating tidal currents, not tidal waves, that cause the coastal tides. As these currents hit the coast, they convert kinetic energy into potential energy and so the water rises locally.

I get about 1.7 x 10^-6m/s² for the tidal acceleration, which is close enough to what you got. This is too feeble to lift any water! It can however cause a current. For a better explanation, visit my site and download a free chapter of my eBook from: tidal gravity.

Regards, Jorrie

Hi Jorrie,

how do you arrive at

this value of 1.7x10^-6 for the tidal acceleration?

My calculation was:

First part: centrifugal forces:

lunar period is 28days that is roughly 2.3 million seconds,

angular velocity omega is 2pi/period = 6.3/(2.3x10⁶) or 2.7x10^-6rad/s.

Centrifugal acceleration (a) is Radius (r) times omega² or:

with a radius of 1500km a=7.3x10^-12x1.5x10⁶m/s² = 11x10^-6m/s²

with a radius of 10500km a=77x10^-6m/s²

The radius of 1500km is valid at the moon-near side, the radius of 10500km valid at the other side.

Second part: gravity forces or acceleration aG:

aG=Gxm/r² where G is the gravitational konstant of 6.7x10^-11, m is the mass of the moon with 7.3x10²²kg and r is the distance to the moon or approximately 384x10⁶m

so aG = 33x10^-6m/s²

At the moon-near surface of earth the accelerations are adding so (33+11) or

anear= 44x10^-6 and on the other side subtracting (77-33) so almost the same value.

The eartg gravity field is diminishing with two times the ratio of heigth above ground to earth radius. At 6.3m high (or 1ppm of earth radius) it should loose 2ppm strength or 19.6x10^-6m/s².

So there should be a tidal water high as much as 13m!, what is wrong with this calculation? This is near a factor of 30 too much.

To my understanding one error may be the changed shape of the surface so it is not allowed to take the undisturbed change of gravity with heigth.

Do you have better data? Or is the tide highly damped?

Concerning your model of energy loss in the bending earth crust there is to be added that there is no stretching but pure bending: 10 to 20cm of amplitude around the earths circumference of 40000km. If you calculate strain from this it should be near 10^-8 . Shall this small strain cause severe energy losses?

Regards

RHABE

Hi RHABE, you asked: "how do you arrive at this value of 1.7x10^-6 for the tidal acceleration?"

The tidal forces can be represented by an acceleration of: ~2MGd/r³, where M is the mass of the primary body, G is Newton's gravitational constant, d is the difference in distance from the primary body between the two points of interest and r is the distance from the primary body.

The link that I gave before on tidal gravity, has a .pdf that explains the phenomenon. I think that the method you used is full of pitfalls - I do not have the time now, but I will work through it later and try to point out your mistake (if any!)

Regards, Jorrie

Hi all. RHABE asked: "how do you arrive at this value of 1.7x10^-6 for the tidal acceleration?" and I replied "The tidal forces can be represented by an acceleration of: ~2MGd/r³"....

In the meantime, if anyone wants to check my calc, I included the Moon and the Sun (lined up). What I called "mass of the primary body" M is the mass of the body causing the tidal component (Moon or Sun), r is the applicable distance of that body and d is Earth's radius.

This is the modern way of looking at tidal gravity - no centrifugal forces around the "barycenter" to make things difficult!

Regards, Jorrie

Hi RHABE, I spotted your error, not in a calculation, but in logic. You wrote: "Centrifugal acceleration (a) is Radius (r) times omega² or:

with a radius of 1500km a=7.3x10^-12x1.5x10⁶m/s² = 11x10^-6m/s²

with a radius of 10500km a=77x10^-6m/s²

The radius of 1500km is valid at the moon-near side, the radius of 10500km valid at the other side. "

The 11x10^-6m/s² is valid, but then you apply a radius of 10500 km to the other side, as if Earth is turning around the barycenter! In barycentric coordinates, the whole Earth undergoes the 11x10^-6m/s² centrifugal acceleration, always away from the moon. Earth wobbles around the barycenter, it is not rotating around it in the same sense that it is rotating around its centre of mass.

Now one has to calculate the moon's gravitational acceleration effect on the far and the near side, giving about ~32x10^-6m/s² and ~34x10^-6m/s² respectively, while it is ~33x10^-6m/s² at Earth's centre.

What is important now, is the difference between the centre and the two sides respectively. Since the centrifugal components are the same everywhere, they cancel out. So, there is ~1x10^-6m/s² difference between each side and the center, working against normal surface gravity.

When I add the Sun at alignment and do the sums more accurately, the answer is ~1.7x10^-6m/s², which is, hmm... ~0.2μg. Tiny!

BTW, there is a "squeeze" of also ~0.2μg working with surface gravity at points 90 degrees from the direct overhead position of the Moon+Sun.

Regards, Jorrie

Hi, Jorrie!

Not being an astrophysicist, but just a plain ol' Marine Engineer, I found myself struggling as I pursued your response to RHABE above.

For example, it's very interesting news to me that the earth's shape is affected by its proximity to the moon. Why is this an important factor?

I don't want to become an instant astrophysicist , but I wonder if you would be so kind, in a very few words, to sum up the gist of your explanation to RHABE in slightly (perhaps not so slightly) less-than-technical terms, so I can have another, more understanding look at the math to try to better understand the point you are both making, especially in your last two paragraphs re the sun and the squeeze.

Mark

Hi Mark, you wrote: "... so I can have another, more understanding look at the math to try to better understand the point you are both making, especially in your last two paragraphs re the sun and the squeeze."

OK, firstly, RHABE did it the hard way and got "stumped" in the process! (In my cricket-mad country, this term might come up more than what is decent during the ICC world Cup, I suppose).

I hope I have shown that the centrifugal forces around the barycenter (center of mass (or COM) of the Earth-Moon system) cancels out and have nothing to do with the tidal gravity on Earth.

Taking that at face value, what remains is the fact that the Moon (and Sun) pulls the near side of Earth (at any moment) a bit harder than the far side. What is very important is that the COM of Earth is the one that determines the overall accelleration of the planet towards the Moon-Sun combination.

Now, the near side of Earth will have somewhat stronger gravity (0.17μg, as I have stated before) than the center. Likewise, the far side will feel the same amount less gravity than the center. Result: Earth gets stretched a bit.

The "squeeze" is a simple effect caused by the fact that the gravitational vector works towards the centre of the Moon (or the Sun). This means that for the 90° positions from the direct line, it is always somewhat inward! Draw a sketch and check it...

I hope this helps a bit. My chapter on tidal gravity in Relativity 4 Engineers does a better job of explaining, I hope! Download a free chapter from: Tidal Gravity.

Regards, Jorrie

Hi Jorrie,

your website and your calculation is fine and ok, but it is only considering the dependance of gravitation with distance.

The centrifugal acceleration is missing???

Why can you state that the centrifugal components are the same everywhere?

I don't believe this unless you have a proof.

I found my error but I have to trace and renew the result.

Regards

RHABE

Hi RHABE, you wrote: "Why can you state that the centrifugal components are the same everywhere? I don't believe this unless you have a proof."

You do not find this in many books - I think the NOAA websites article "Our Restless Tides" has something to this effect.

Anyhow, if we consider the Moon only, I think you would agree that it is Earth's center that moves in a rough circle (rough, because it' really an ellipse) around the barycenter once in 28 days, with a radius of ~1500 km. So the center suffers a centrifugal acceleration of 3.3μg, always away from the Moon.

Earth's rotation is not coupled to this period in any way whatsoever, so one can ignore the normal 24 hour rotation. Let's say Earth always points the same face at the Moon (as the Moon does to Earth). What will the centrifugal acceleration caused by the rotation around the barycenter be at any point on or inside Earth? - 3.3μg pointing away from the Moon.

A more engineering "proof" is to attach a wheel with a wheel bearing to an bent axle, say like this:

(Drive axle here) -----|_____(wheel here). Rotate the axle from the left...

Irrespective of any spin that the wheel may have, there will always be an additional centrifugal force working away from the drive sides centerline.

Regards, Jorrie

Errata - I wrote: "So the center suffers a centrifugal acceleration of 3.3μg, always away from the Moon."

Should read 1.1μg in both places where I used it, as calculated before for the Moon only.

Further, I should have said "centrifugal force" and not "centrifugal acceleration". Otherwise it could have said centripetal acceleration, always towards the Moon.

Regards, Jorrie

THE CURRENTES at various places could create much power, look at the canal up in rhode island, there is a snake paddle in the currents creating large amts of power at low rates.

this was written up in a few magazines & if this method was expanded to the east gulf stream the power would be great at a low cost and it would be endless.

Gwen IN REPLY TO Your ENERGY HARVEST QUESTION!

IF THE LARGE POWER PRODUCERS I.E. Channel currents THEN A SECOND PHASE COULD USED EATHER RIVER CURRENTS OR TIDE CURRENTS to replace currents that slow or become non currents for a few hours of eather tide change or low water because of drought or rechanneling of resources. this way there always is a current to produce power.

IT TAKES COORDINATION OF RESOURCES to have all prosper instead of a particular state it should be a national direction because there are always areas that prosper with weather changes and others decline because of other changes.

With a national coordination of resources vast amounts of power could be produced & routed to were it's needed, this wound reduce the overall cost of power nationwide.

Tidal energy is quite well distributed. Even on our 60km coast the tides are not the same.

If you would combine the current in the channels of Calais and Gibraltar the dead moments would be very low.

Overpower can be stocked in hydro gravity systems (even with seawater in the North African desert, to give them a piece of the money cake + some more evaporation can be handy in a dry area)

Wind can help the mainland (which is mainly flat) and we should invest in systems to harvest the solar heat in summer and to use it in winter.

Gwen

Hi Gwen,

Probably the place that is most suitable for using tidal power is Auckland, New Zealand. Auckland has two harbors that are separated by about 5.25 Km at their closest point. The part that makes it really suitable is that the entrances to the harbors are on the opposite side of the North Island. Because of this the tides in one harbor lag those in the other by about 2 hours and 44 minutes.

I know that the concept of using the difference in tides was looked at a long time ago and dropped because it was not economically viable but apparently it has been resurrected and may be a reality after all.

I'VE BEEN TO AUCKLAND & SAW THE TIDAL CURRENTS & THEY SHOW MUTCH PROMISE IN POWER PRODUCTION. THE IMPORTANT ITEM IS THE SELECTION OF A GENERATOR TO PRODUCE THE MOST POWER AT A LOW COST. THERE IS A SNAKE GENERATOR THAT IS USED AT A RHODE ISLAND CANAL THAT CREATES A LOT OF POWER AT VERRY LOW COST. WHATS THE BEST IS A 24 HOUR FLOW SO THE POWER IS CONSTANT BUT I GUESS YOU CAN SEGMENT THEM TO EXTEND THE POWER GENERATION DAY. WITH UNDER WATER CABELS ONE COULD SEND THE POWER TO MANY AREAS OF AUCKLAND TO POWER MULTIPLE CITIES AT THE SAME TIME.

HI ALL !

I DID some research & i found that the gorlov helix turbine is the generator i was talking about being used on cape cod in rode island check out WWW.commondreams.com and read the story about it, you all can take advantage of this technology improvement for most water situations to generate power at low cost.

it took a while to find it but i succeeded ****** enjoy !

goldrushnugget999

You certain this is the correct website?

Mark

HI AGAIN !

I HAVE A CORRECTION ON THAT WEB SITE IT'S WWW.commondreams.org

SORRY ABOUT THAT.

goldrushnugget999

HI Gwen !

I did some research on a water turbine that was used on cape cod, rode island a few years ago, it's the gorlov helix turbine check out www.commondreams.org for an explanation of this most important invention for a water turbine.

goldrushnugget999

I have been considering this for a while and there are a few sea power items you or your replyers have not mentioned.

there is a five to ten not force that goes UP the east coast that is called the gulf stream.

this stream is a flow of warm water in a cold water area and using a sterling engine & a 20 degree temp flux to power it many generators could be run to creat vast amounts of power that would be low cost and limetless because all thats needed is just lower another generator to increase the power output.

there may need to be director paddles to increase the temp flux, or a wheel could be used to spin the generator. the wheel has a retractable paddle to decrease drag in the water.

that would call for a new design for a paddle wheel or a sterling engine that will run with a wheel for assistance to get two kinds of power usage, temp & force.

It might be advisable to leave the gulf stream as it is: we need him to heat our regions. (Western Europe)

There are also signs that this gulf stream is stopping: it is driven by the cold salty water (cold and salty due to evaporation between Norway and Greenland) that moves over the sea-bottom from Greenland to the Gulf of Mexico.

The massive amount of fresh water from the Greenland glaciers is mixing with this water and reducing the salinity, taking away the force to push the water down.

I must admit I havn't played with Sterling engines but from what I have read about them the power to weight ratio is pretty poor.

If you were to use the gulf stream to generate power I think there would be much more cost effective methods than the use of Sterling engines.

One thing that would be worth looking at is the effect that sucking energy out of the gulf stream could have on it. I don't know as I have no idea how much energy there is in the gulf stream but if you sucked too much out and the system collapsed the effects could be catastrophic.

Hi Masu,

the gulf stream has not enough velocity to be important.

As Gwen stated it is driven by the sinking of cooled down salty water near Iceland and this is not much drive for a 6000km long current.

Better think about the tidal driven stream between Sicily and Italy, the famous Scuilly and Charybdis of Homers tale of the odyssee.

There are high velocities (more than 10km/h) in thre 4km wide by 0.4km deep marine street of Messina.

But how to establish turbines that can catch this energy?

Same with Gibraltar (but driven by evaporation generating 0.8m difference in the mediterranean to the atlantic).

Maybe continental plate tectonics is faster in closing this again (as existing between 15 to 20 million jears ago until 6million years ago).

I don't think that we ever will arive at this large scale projects but we shall do a calculation: how much water is evaporated yearly. It would take 4000years to have the mediterranean level go down to minus 3000 m. This shall be enough for calculation.

But: who will accept this? I think nobody will.

But: at that time there was a really hot climate in now moderate latitudes: crocodiles living in central Europe. In contradiction to todays rumor about global warming connected to sea level rising at that time the sea level was down minimum 100 m! So when is warming causing sealevel rising and when falling?

RHABE

But: at that time there was a really hot climate in now moderate latitudes: crocodiles living in central Europe. In contradiction to todays rumor about global warming connected to sea level rising at that time the sea level was down minimum 100 m! So when is warming causing sea level rising and when falling?

You need to look at what is happening at the world as a whole and not just one region. Local climates have and do vary considerably for a variety of reasons but global changes are somewhat slower and less frequent.

If the global climate changes enough to start melting the ice caps then the sea level will rise. The Antarctic ice cap holds about 30 x 10¹⁵ m³, the vast bulk of the ice and so the melting of this will have the greatest effect on sea levels. The Greenlandic ice cap has a volume of around 2.85 x 10¹⁵ m³ and so would have proportionally less effect.

I will leave it to you to do the arithmetic but if the Greenlandic and Antarctic ice caps melt a not insignificant number of people are going to need to do a lot of swimming to get around as a considerable number of the worlds major cities are going to be under water.

I wouldn't call global warming a rumor, there is a lot of evidence to show that it is happening and it could have some very serious repercussions.

Hi Masu,

you are right as long as you consider warming to extend to the polar regions where the ice is existing and storing volume above sealevel.

But if the temperature in moderate latitudes goes up and the temperature in arctic and antarctic latitudes goes up also but remains for long enough of the year below zero then everything is different:

There will be much more evaporation as this is driven by temperature and warm air can hold much more watervapor than cool air.

This much more evaporation is partially deposited in the polar caps and thats why the sealevel can be low at high mean temperatures on the earth.

In the period of warm climate 15 to 5 million years ago it was warm, very warm from central Europe down to southern Africa. I did never see fossil evident of other places but I am convinced that these exist.

Together with this warm period the sea level was down at around minus 100m compared to todays sealevel. So there must have been a gigantic storage of water in the icecaps including the dry mediterranean that was the cause for that extended warming.

These are geologic facts. What is missing is an explanation if the icecaps can melt down to an extent that we should fear or if this accumulation at the polar regions will overcompensate the partial melting.

We humans are existing only because this geologic warm period, as our ancestors lived at the coasts of Africa, learning upright walking and use of tools. We do not find the fossils from that time as these are -if any are existing- submerged deeply in some river deposits below sealevel.

Many often scientists capture only half of the story and add additional data to modeling systems later if the predictions of the system fail.

Regards

RHABE

So there must have been a gigantic storage of water in the icecaps including the dry mediterranean that was the cause for that extended warming.

I think you will find that when the Mediterranean Sea was dry or had a considerably lower level that it was not connected to the worlds oceans. Geologically the Strait of Gibraltar is a relative recent event and opened up allowing the Mediterranean Sea to fill.

I agree that the whole thing is very complex but there is ample direct evidence that the Greenlandic and Antarctic ice sheets are in fact melting. Glaciers are retreating at an alarming rate in Greenland and December saw ice bergs off the coast on New Zealand so there is definitely something wrong. I hope it isn't as bad as some are forecasting but to ignore all the warnings and do nothing would be catastrophic. If we act and it turns out not to be as bad then there isn't a problem, if we fail to act at all and it is only half as bad we are in deep trouble. To not take action now whiled we have time would be criminal.

"I think you will find that when the Mediterranean Sea was dry or had a considerably lower level that it was not connected to the worlds oceans"

Hi Masu,

naturally you are right, that the strait of Gibraltar was closed. How else can the sea level be down? The evaporation of the mediterranean sea is around 80cm more than the influx from rain and the rivers.

So after closing it took around 5000 years to bring the level down. Any place on earth lower than the sea will act as an energy trap: collecting visible light and convert it to thermal (infrared) energy that is prevented from escaping by dust, haze and humid air. Similar but small scale is existing in death valley and dead sea.

As the surface is around 3million square km, this can generate 3000 Gigawatt if the sealevel is down 4000m of hydropower, unrealistic today but worth while to evaluate.

Smaller projects with pipelines to the Kufra oasis in Egypt and to the dead sea have been debated since 50years or longer but never came to reality.

"I hope it isn't as bad as some are forecasting but to ignore all the warnings and do nI hope it isn't as bad as some are forecasting but to ignore all the warnings and do nothing would be catastrophiothing would be catastrophic"

You state this but you cannot be shure. I am convinced that there will not be enough response to energy saving - the only way that will work efficiently in short time- so that we will have some global warming.

How good or bad this will be we do not know. So acting now and wasting resources can be dangerous because we will not have these resources for other necessary issues.

I am convinced that we need this money for a much better education than is existing today. With this we will have the engineers and scientists necessary to react in time.

Else we will be beautiful energy savers but unable to live with changing challenges.

Look at the situation of cultures that did not survive: they were stuck with sound decisions but these were wrong!

The long walls of Athens, the limes of Rome, the great wall of China, the communist wall in Europe, the spanish and portugies fortunes spent for castles, churches and monasteries but not for forest growing to have enough wood to build a new fleet every 5 to 10 years.

Our walls and pyramids and castles will be the energy saving rush as long as it is not sound: energy efficient and not costing more than gained and not depleting others from food.

Russia, China, bot Americas and others will largely laugh at us and do a little bit but not at all enough to prevent rising CO2.

What will be the consequences of rising CO2 is not at all clear. "All" scientists declare today that we will have problems but that is a well known szenario. So I am sure that the real outcome will be much different than the today fears predict.

The climatic changes of the past have been much bigger than anything we will accept. But nobody has a sound theory what triggered these and where are the up- and downregulating factors. We know around 20 of these influencing factors but we don't know how these factors act and interact.

Else we could predict and explain the different sealevels of geologic records.

So I would plead that everybody should do energy production and enrgy saving as soon as there is a return on investment that will pay for all cost within 10years.

Normally this is 3 years!

Anything else will waste our resources that we need badly. If we do not make sound decisions our nations will be "banana republics" in 20 years and no more of any industrial significance. And this is much worde than any worst case of global warming.

RHABE

RHABE,

I'm not completely agreeing with your comparison of our efforts to gain energy out of natural processes and the wall from the past.

The walls were a way to protect against changes and to make sure that they would not influence the settled society. It is a negation system: no the world does not change, this wall proves it.

Windmills are a way to cope with the changes that we are facing: how to make use of our changing environment.

The reaction of the big "oil" lobby is comparable with the old fashioned wall: we tell you there is no problem and you don't need to look at it, it are all lies, just continue as we want it.

The inverse might be happening: we can continue to live at our standards and the negating industrial countries will have to face the results (flooding, hurricanes, diseases, pollution,... and energy shortage)

The negating had always the same effect: the living standard was going down until the system collapsed.

You are right on education: a big part of the needed investments are education to make sure that the next generations don't make the same mistakes.

We were able to counter nationalism and to bring peace in Europe. Merely through decent education, based on facts and science. Now we need to bring up the new members to the same standards and add environmental knowledge.

Gwen

Dear Rhab,

You state this but you cannot be shure. I am convinced that there will not be enough response to energy saving - the only way that will work efficiently in short time- so that we will have some global warming.

How good or bad this will be we do not know. So acting now and wasting resources can be dangerous because we will not have these resources for other necessary issues.

Initially when the concept of global warming was first put forward they were predicting a 1°C temperature rise by the middle of the 21^st century. Australia has already experienced a 1°C rise in mean temperatures since the middle of the 20^th century.

Whilst it is true we can't be certain of the ultimate effect or actions will have on the environment I believe there is now sufficient evidence that we are having an effect and if the current trend continues it will be towards the high end of the original estimates.

I am convinced that we need this money for a much better education than is existing today. With this we will have the engineers and scientists necessary to react in time.

You have raise the separate issue of the apparent falling standards of education and like you I find this or great concern. In general each generation has had had access to and benefited by an ever improving standard of education. The introduction of the internet has increased our access to information in a way that was unimaginable half a century ago and it has a profound effect on society. Even so there seems to have been a slip in to overall level of education and the gap between the well and less educated has widened.

Having said that I don't see why we can't improve the standard of education and investigate every possible solution.

We do not pay the true price for fossil fuels as it dose not include the cost that the burning of these fuels is doing to the environment. Ultimately we are subsidizing the use of these fuels and the profits of the companies that develop these resources with the future cost or negating the effect on the environment. This subsidizing is also making the development and use of alternate ecologically sustainable fuels un-economic. If we were to include the cost of the environmental damage and pay the true and total cost for these fuels then they would quickly become uneconomic and alternate sources would quickly supplant them.

We have been subsidizing fossil fuels and the profits of the people that develop and distribute these fuels since the beginning of the industrial revolution and the time to pay up is rapidly approaching. The sooner we remedy this false economy the lower the ultimate price will be.

We are seeing record temperatures world wide, the Greenlandic ice sheet is retreating and there is evidence that the Antarctic ice sheet is melting and we may be seeing the first refugees of global warming with the Carteret People needing to abandon their island paradise that they have called home for four centuries.

I must therefore respectfully disagree that we should proceed cautiously. We must maintain our standard of education and investigate and develop every technology that show promise in reducing our dependence on fossil fuels. The sooner and more decisively we act the less the ultimate economic, social and environmental price we are forced to pay will be.

Why would you close the Gibraltar Channel.

Just install some submerged turbines, they will influence the stream and over a serious length of time the water level will drop with some cm, which pulls in more water and we have more energy generated. (as the see level is expected to go up with some m they will not notice this cm in Nice.)

Payback will be faster than any other system.

Why was it so warm in Europe? the Mediterranean was empty, sun could heat up freely, no evaporation as today.

The fact that the general see level was 100m lower could also be found in geological activities: High mountains that contained lots of snow and ice completely flushed into the see. The big earthquake from Christmas 2004 also influenced the see-level and the earth rotation speed.

OK You need a lot of disasters to modify the see level in that way. But what is going to be the effect of our actual heating on the Goby? when they get some rain it will become ice, and slowly the see is transferred to land ice again. We know that the Alpine glaciers are remains of the ice ages and the Sahara once was a big forest.

It is also known that the high glaciers in Scandinavia are growing, they are still in a region that is cold, on Spitsbergen the snow is on the beach, only melting in high summer. Warmer oceans will generate more snow in these regions so that their glaciers will start to grow again, but it will take some time before the see level is going to go down. The inverse effect of melting Greenland and Antarctica is bigger.

Where I live we have deposits of stones from the last ice age, the complete region is shaped by the end of the big glacier. Where did it go? To build such a glacier you need to have hot and cold regions both exceptionally, and it took thousands of years to build it up and to melt it away.

At several places in the world they use fossil water to irrigate the land, this water is also added to the see.

What is going to be the biggest effect of tidal and wave generation: the slow down of the earth or a cool down of the see? I guess that the cool down is going to be bigger. (The extracted energy would be transformed to heat by friction when we don't harvest it)

Gwen

Man! What a phenomenal original idea! True genius of innovation. Can't say enough good things about this thought. Thanks.

Ceraintly, to worriers about its effect on the gulf stream current itself, I think that since the energy utilized in the Stirlings is just the temperature differences of the two flows, there would be little -in all probability zero- impact felt by the temporary use of those temperatures to drive the generators.

Any other ideas on this idea's eco-impact?

Mark

MARK ! THERE ARE ALSO SNAKE GENERATORS WHICH HAVE BEEN EMPLOYED IN THE RHODE ISLAND CANAL THE CHANGES IN WATER FLOW WAS ENOUGH TO GENERATE A LOT OF POWER. IF THESE CAN BE DEPLOIED IN THE GULF STREAM IT WOULD ALSO PRODUCE A LOT OF POWER AT LOW COST.

Goldrushnugget999

It just occurred to me that wherever there is a naturally-occurring thermocline, there is a lovely source for Stirling employment.

Rhabe

If you've been swimming in any body of water where you can suddenly feel the temperature difference between current flows (they're not so geographically distant from one another, often just side-by-side), you'll recall that the Stirlings would not have to be massive to be deployed as Goldrushnugget999 suggests.

Mark

MARK !

NOW YOU ARE GETTING THE FUTURE OF POWER !

IT could be cheap and plentyfull, IF WE NOW START TO TAKE ADVANTAGE OF THE UNNOTICED RESOURCES THAT ARE THERE FOR THE HARVESTING.

IT may take years to develope but we need to plan & start creating a tap of this resaurce, it takes a coordinator to begin assembling the resourses & Raising the Capitol to set up this project. this is a large project that can take years to complete.

BUT THE REWARDS ARE GREAT & I BELIEVE THEY ARE WELL WORTH THE INVESTMENT.

THIS TAKES A LARGE EFFORT AND IT WON'T HAPPEN WITH THE CURRENT POLITICOL SITUATION IN THIS COUNTRY, THE FAT CATS CAN'T GET FATTER.

HI THREAD MEMBERS!

TODAY I came accross an article in ENERGYBIZ MAGAZINE ABOUT THE POWER OF THE TIDES. I Thought it would go along with this discussion, THE MARCH/APRIL ISSUE.

ON PAGE 64 THE article talks about a pilot project in NEW YORK's EAST RIVER USING A NEWLY DESIGNED WATER TURBINE THAT PRODUCES UP TO 32 KWS of electricity through tidal & river currents. there were 2 turbines lowerd into the river, one was tested to a high speed that the fins snaped off, i heard it put out about 48 kws, the design needs to be alterd but the speed is there and the power produced is great even if it is only a test. THE PROOF IS THERE, THE TIDAL POWER & THE CURRENTS CAN PRODUCE UP TO 30,000 megawatts to 50,000 megawatts estimate by this article. WWW.ENERGYCENTRAL.com/energybiz

The energy of the restless sea is dissipated upon itself and upon the beach where the waves do crash. Would the diversionary harvest of just a little of this energy take any more than an iota of warmth from the oceans or the beach?

HI !

It may not be on the beach but in the deeper waters with waves of currents that different forms of energy can be harvested. when you read the blogs of several links most of the energy water forms are coverd. very few beach power forms are included.

goldrushnugget999

I suppose that the power we would take results in a lower temperature level of the sea (measurable??).

It would be great: the sea is getting to hot, resulting in lot's of different other problems.

I just happened to notice this interesting link on this subject. The pdf version is reachable using the keywords "Israel" "tidal" and "electricity", because I once read an article that says Israel actually has a major tidal electricity production facility. Not having the patience to deal with the PDF version, I downloaded the html version at:

http://64.233.167.104/search?q=cache:paskTduzoLQJ:www.crest-energy.com/docs/doc004.doc+Israel+Tidal+Electricity&hl=en&ct=clnk&cd=2&gl=ca

Mark

Hi, Macker!

Nice stuff. Enjoyed checking it out. Thanks for the writeup. Score 1 for the well-written opporutnity to extend my information base.

Mark

G'day Macker,

Great post. Introducing new technologies and discussing them openly is exactly why this blog was started.

Interestingly the idea of the vertical helical submarine turbine has also been used as a wind turbine. It's evidently far quieter than the usual wind turbines and not as difficult to set up as you don't need to have a thumping great generator on a 50 m high pole that can pivot with the wind.

I'm also interested in you're design of a wind turbine so please if it's not letting any secrets out keep us informed of your progress.

I'm personally located near the coast in Sydney and not long after noon each day there is normally a sufficient temperature differential between the terrestrial and marine air masses to give us a fairly reliable sea breeze making wind turbines a distinct possibility.

Currently Origin Energy Australia have a solar cell based co‑generating system that can distribute surplus generating capacity over the existing power grid that offsets the energy you consume. While it is currently only available with solar cells I can't see any reason why the unit that interfaces with the grid couldn't use a wind, hydro, geothermal or any other type of generator instead of or in conjunction with the control/inverter that is the heart of the system.

I'm pretty limited in what I can do but if you think there is anything I can help you with pleas don't hesitate to drop me a personal message and I will do whatever I can.

Regards,

MASU