For some strange reason this old head was trying to sort out where tidal power comes from.
Unlike most other forms of power we have available, (apart from nuclear) that are directly or indirectly powered from the sun. As far as I can figure out, tidal power is drawing on the Earth's flywheel energy.
So does the tidal power we use slow the Earth down?
If so how?
I just can't get my head around this puzzle.
I guess there's a huge amount of energy stored in the earth's rotation, and it would take a very long time for the amount of energy we're likely to draw from it, to make a noticeable change in day/night length.
Nah its all good, most hydro energy comes in the form of water turbines,as the tide flows through the turbine spins and creates electricity,through diodes or mechanical gears, think of like the old water wheels.
However the resistance does slow down the tide and can disrupt fish breeding and ecology/waterflow to a degree particularly if there are dams and weirs involved.
As a side note they reckon if they could capture half the "lost" energy in the pilbarra during the wet from big rains it could run all of Wa easy.
A couple of the big players rio/bhp looked at it pretty seriously for a while but it ended up fizzing out.
If you google the snowy mountain irrigation scheme it will give you an idea, however its more reliant on gravity than tides but similar in principle.
Final answer, Tides are dependent on the moon so they run seperatley to the earth, as the moon goes through phases and orbit its gravity will have different amounts of "pull" over the earths water/surface friction. This results in differing tidal patterns throughout the moons orbit and proximity to earth.
A month is really a moonth which is one cycle of the moon, full to new, this equates to 29.53 days which although not perfectly aligned with our calander gives a close approximation.
If we run off a lunar year however it does not synchronize with the seasonal year,hence the leap year and 365 days to keep us in sync.
Many scientists (and nutcases like myself) believe this relationship with the moon and its affect on our gravity assist with keeping us in what can only be described as a perfect orbit, kinda like two magnets pushing and pulling.
As an additional waffle all women used to get their period on the full moon and the men would go hunting. (cause the men were super smart back then)
Nowadays due to artifical light and the changing of peoples circadian pattern this is not the case. Although if you put 4 women in one house they all bluetooth in to each other and its hell for any male in that house for a period of 3-7 days per month.
Anyway enjoy
I have no idea what it would do to the Earth's rotation. We need another well thought out response from Ian K.
www.bbc.com/news/science-environment-12311119
"The Moon continues to spin away from the Earth, at the rate of 3.78cm (1.48in) per year, at about the same speed at which our fingernails grow.
The Moon is kept in orbit by the gravitational force that the Earth exerts on it, but the Moon also exerts a gravitational force on our planet and this causes the movement of the Earth's oceans to form a tidal bulge.
Due to the rotation of the Earth, this tidal bulge actually sits slightly ahead of the Moon. Some of the energy of the spinning Earth gets transferred to the tidal bulge via friction.
This drives the bulge forward, keeping it ahead of the Moon. The tidal bulge feeds a small amount of energy into the Moon, pushing it into a higher orbit like the faster, outside lanes of a test track.
This phenomenon is similar to the experience one feels on a children's roundabout. The faster the roundabout spins the stronger the feeling of being slung outwards.
But the energy gained as the Moon is pushed higher is balanced by a reduction in the energy of its motion - so an acceleration provided by the Earth's tides is actually slowing the Moon down."
Thanks Elroy, nice short understandable vid. So the friction of tides over the ocean/sea floor slows the earth down, I guess turbines in the flow has the same effect, and adds to that slow down.
The earth won't be such a nice place once it stops rotating, but humanity probably won't be around then.
When is the sun due to do it's red giant thing?
Elroy jetson is pretty bang on, in relation to orbit, its also of note that the more oil and liquid we pump out of the ground and burn/carbonize turn to solids gas will have an effect on the free surface effect of the earths magma/core and our gravity relationship with the moon. The more we pump and burn, the less mass we have and the less gravitational strength to keep our sync with the moon. You must take into account that although it may seem a trivial amount of mass, over years and decades it can and will have an effect. Apparently there is a couple nuclear power stations that if all ran at 100% would slow down the spin of the earth.(How this works i dont know google it for a brief)
If humans were really smart/or stupid with the right application of what we know we could actually escape the suns orbit and use the moon to propel through space. There is of course problems like we dont have the technology/infrastructure to do this....but it could be done maybe one day, we may have too when the sun burns out and were doomed as a race..4000000 years from now, There is a whole heap of debates in regards to the sun and its gravity and whether its fission or fusion reaction. I spent some time doing cellestial navigation when I was on the boats and the more I learnt the more interesting it became,it also become really really confusing due to the fact a lot of science is still only theory and not law or fact. Than when you think you have an idea you read something legit that blows your mind and is completely revolutionary to how you were taught and quite often conflicting. It was at this stage I became more of a philosopher than an educated cellestial navigator because frankly I realised not only did I know nothing but both sides of the conflicting views also knew nothing.
Sorry back on topic
they reckon the sun has another 4billion years of stability, however there is a large scientific war in regards to this. Im not starting a conspiracy war but have a bit of a google
I just did a quick calculation:
The Carnegie tidal power station at Garden island would have to operate non stop for 1000 million years to slow the rotation of the earth by 5 milliseconds.
The dissipation of energy by tidal friction on earth averages about 3.75 terawatts, slowing the rotation of the earth by 2 milliseconds a century
Carnegie wave energy plant at Garden island produces 250kW of energy. Lets assume it dissipates 1000kW of tidal energy. Which is 0.000001 terawatt
3.75 / 0.000001 = 3 750 000
2 milliseconds divided by 3 750 000 = 0.00000053 milliseconds a century
0.0053 milliseconds every million years
Or 5.3 milliseconds every billion years
Select to expand quoteElroy Jetson said..
I just did a quick calculation:
The Carnegie tidal power station at Garden island would have to operate non stop for 1000 million years to slow the rotation of the earth by 5 milliseconds.
The dissipation of energy by tidal friction on earth averages about 3.75 terawatts, slowing the rotation of the earth by 2 milliseconds a century
Carnegie wave energy plant at Garden island produces 250kW of energy. Lets assume it dissipates 1000kW of tidal energy. Which is 0.000001 terawatt
3.75 / 0.000001 = 3 750 000
2 milliseconds divided by 3 750 000 = 0.00000053 milliseconds a century
0.0053 milliseconds every million years
Or 5.3 milliseconds every billion years
I dont think your answer is correct! Ya forgot to carry the 1!
Select to expand quoteElroy Jetson said..
I just did a quick calculation:
The Carnegie tidal power station at Garden island would have to operate non stop for 1000 million years to slow the rotation of the earth by 5 milliseconds.
By that time the moon which is moving away from Earths gravitational affect, will have moved significantly far enough away (moves slightly away each year) that the tides wont be tides worth mentioning, and the Carnegie guys will be out of work
Select to expand quoteRazzonater said..
The more we pump and burn, the less mass we have and the less gravitational strength to keep our sync with the moon. You must take into account that although it may seem a trivial amount of mass, over years and decades it can and will have an effect. Apparently there is a couple nuclear power stations that if
Is that suggesting we have worked out a way to make matter disappear?
Burning fossil fuels won't make the earth lighter.
Select to expand quoteDawn Patrol said...Razzonater said..
The more we pump and burn, the less mass we have and the less gravitational strength to keep our sync with the moon. You must take into account that although it may seem a trivial amount of mass, over years and decades it can and will have an effect. Apparently there is a couple nuclear power stations that if
Is that suggesting we have worked out a way to make matter disappear?
Burning fossil fuels won't make the earth lighter.
yes,yes it will if you have liquid trapped in the earths surface than extract it change its state to gas.....the only thing left is carbon/waste and the gas it makes Co2 for example, multiply this by the 50litres of petrol you put in your car a week x the other 5million registered vehicles in Oz......plus the haul paks on mine sites,the graders,the excavators diesel generators etc etc......multiply that by the world and whammmo
Tidal power systems act as a shock absorber on the movement of the earth's tidal flow, that is, they restrict the movement of the tide, but to a minuscule amount considering the huge volumes of water movement worldwide.
As such. all energy extracted by this method must act to slow down the earths rotation.
It's not a renewable resource. It is not replenished by anything which would add momentum to the earths rotation.
It has no real effect at the moment because there is very little energy derived from tidal power.
If it ever became a major contributor to the planets power generation it would have a more significant effect.
Another thing which affects the planets rotational balance is the recent shipping of hundreds of millions of tons of iron ore every year from the southern hemisphere to the northern hemisphere. Most of the products made from this remain in the northern hemisphere.
It's a bit like moving the balance weights on your car wheel and then wondering why the wheels wobble.
Eventually this will have a noticeable effect.
One day we will awake to find the earth has fallen over. 
Well, maybe not quite,.. 
but it must have some effect. 
One day I will come back and read the other responses, but the tides come from the moon, so slowing the tides must slow the moon. Now basic physics will tell you that if you slow the moon, it will crash into us, so tidal must be bad, mkay.
Select to expand quoteDawn Patrol said..Razzonater said..
The more we pump and burn, the less mass we have and the less gravitational strength to keep our sync with the moon. You must take into account that although it may seem a trivial amount of mass, over years and decades it can and will have an effect. Apparently there is a couple nuclear power stations that if
Is that suggesting we have worked out a way to make matter disappear?
Burning fossil fuels won't make the earth lighter.
As DP says ; Changing the state of a thing and releasing energy, increases entropy and the distribution and form of mass, but can't change total mass...
Select to expand quotepweedas said...
Tidal power systems act as a shock absorber on the movement of the earth's tidal flow, that is, they restrict the movement of the tide, but to a minuscule amount considering the huge volumes of water movement worldwide.
As such. all energy extracted by this method must act to slow down the earths rotation.
It's not a renewable resource. It is not replenished by anything which would add momentum to the earths rotation.
It has no real effect at the moment because there is very little energy derived from tidal power.
If it ever became a major contributor to the planets power generation it would have a more significant effect.
Another thing which affects the planets rotational balance is the recent shipping of hundreds of millions of tons of iron ore every year from the southern hemisphere to the northern hemisphere. Most of the products made from this remain in the northern hemisphere.
It's a bit like moving the balance weights on your car wheel and then wondering why the wheels wobble.
Eventually this will have a noticeable effect.
One day we will awake to find the earth has fallen over.
Well, maybe not quite,.. but it must have some effect.
Please dont encourage me,but stic a coin to a basketball,spin it on your finger than move the coin offset from the axis/off centre.....you are correct pweedas.
Dawn patrol I am serious,for shizzle
Select to expand quoteRails said...Dawn Patrol said..Razzonater said..
The more we pump and burn, the less mass we have and the less gravitational strength to keep our sync with the moon. You must take into account that although it may seem a trivial amount of mass, over years and decades it can and will have an effect. Apparently there is a couple nuclear power stations that if
Is that suggesting we have worked out a way to make matter disappear?
Burning fossil fuels won't make the earth lighter.
As DP says ; Changing the state of a thing and releasing energy, increases entropy and the distribution and form of mass, but can't change total mass...
Maybe in high school physics, but in reality, mass is lost. How long it would take to cause effect is another topic, particularly considering the already complex material exchange in and out of our atmosphere.
Where is the mass lost to?
As far as I am aware Earth does lose some mass to space. But not as a result of burning fossil fuels.
Select to expand quoteCal said..
One day I will come back and read the other responses, but the tides come from the moon, so slowing the tides must slow the moon. Now basic physics will tell you that if you slow the moon, it will crash into us, so tidal must be bad, mkay.
I'm not sure you've connected these facts correctly, yes tides are caused by the moon, but I'm not sure that means that's where tidal energy comes from.
I'm fairly sure it's sucking the energy from the earth's rotation, fair enough if there was no moon and no tides this wouldn't be possible. The tides are just part of the process that enables this to happen.
Isn't this what's already happened to the moon, it's spin is in sync with it's rotation around the earth, due to the earth's tidal effects on the moon.
So if the moon is slowing the earth's spin, eventually the earth's spin will be in sync with the moon's rotation around us, and we'll have days about a month long.
I think razzonater is saying we're changing the rotational inertia of the earth by shifting mass from below the ground to the atmosphere, intuitively this will slow the spin a bit. But as a percentage of the earth's mass and the distance moved, the effect is not going to be great!
But if we're talking nuclear energy, where mass is converted to energy that radiates into space, maybe, but again the percentages are all wrong for anything noticeable to happen.
Thanks guys for all the responses, turned out to be an interesting discussion.
Slight bit of tongue in cheek when I said the moon will slow and crash into the earth, forgot to use 
There are many papers investigating the loss of mass to energies. I made it clear Im not saying it is significant, was just pointing out it is real.
Should subtext that I studied physics at uni for 5 years, so my humour might have been too subtle.
The moon is moving away, earths rotatIon will slow and we'll be tidally locked to each other. We won't be here to see it though so don't worry.
Does the OP actually mean wave power?
Select to expand quoteKamikuza said..
>>>>
Does the OP actually mean wave power?
No! The energy from wave power obviously comes from the sun, same as hydroelectricity, somebody else mentioned earlier.
If you mean wave power, that is of complex origin (what isnt though). I think the most basic explanation of wave generation, particularly the type driving power generation, is that it is wind powered utilising the distances of our oceans to allow sufficient energy accumulation. Now wind is basically thermally derived, so potentially of solar origin too!
Uni? Back in my day we did orbital mechanics in year 12 physics.
I agree with Elroy. The tidal energy comes from the kinetic and gravitational potential energy of the earth moon system. I might add that although the moon is slowing down it's actually gaining energy by going into a higher orbit. The tidal bulge acts on the moon like you wind up a tennis ball tied to the end of an elastic band. So to run those power stations the earth must lose more rotational energy than the moon gains in orbital energy.
There are many permutations and combinations of the earth's rotation speed and moon orbits that could balance the energy budget to run power stations. To find the one and only solution you could call on conservation of angular momentum. Angular momentum in the earth/moon system is conserved no matter what sort of internal energy exchanges are going on. (Unless of course the sun somehow exerts an external torque on the earth moon system, which maybe it does, you'd need to be someone like Milakovic to work that out)
Select to expand quotedecrepit said..
Kamikuza said..
>>>>
Does the OP actually mean wave power?
No! The energy from wave power obviously comes from the sun, same as hydroelectricity, somebody else mentioned earlier.
You lost me there... Are you talking about electricity generation or something else?
Oh I think I see - from first principles, yeah?
id be more worried about all the satellites and spaceships in orbit slowing us down ;)
Select to expand quotedecrepit said...Kamikuza said..
>>>>
Does the OP actually mean wave power?
No! The energy from wave power obviously comes from the sun, same as hydroelectricity, somebody else mentioned earlier.
Hydro uses gravity, which is not from the sun. UNLESS you mean that solar energy evaporates the water which condenses into clouds that fall as rain which is collected at elevation to store kinetic energy to be turned into power as the water falls through a turbine under gravity?
Select to expand quoteIan K said...
Uni? Back in my day we did orbital mechanics in year 12 physics.
Yes, but it takes more than year 12 physics to develop a nerds sense of humor.
Tidal power is very clearly derived from the relative motion of the moon. A little electricity generation from this will do nothing to the balance of the system and if it helps minimise our effects of the earths climate, it could insignificantly help preserve the balance of the earth-moon symbiosis but that is an enormous bow to draw.
Select to expand quoteCal said..
If you mean wave power, that is of complex origin (what isnt though). I think the most basic explanation of wave generation, particularly the type driving power generation, is that it is wind powered utilising the distances of our oceans to allow sufficient energy accumulation. Now wind is basically thermally derived, so potentially of solar origin too!
A fair component of wind energy is derived from the earths rotation. Which also serves to slow the earth down. Even without the sun, the internal stresses within a gas sitting on a rotating sphere would generate highs and lows.
Select to expand quote>>
>. UNLESS you mean that solar energy evaporates the water which condenses into clouds that fall as rain which is collected at elevation to store kinetic energy to be turned into power as the water falls through a turbine under gravity?
Of course, that's where the energy comes from, you'd soon run out of gravity if that's all you had.
