The true cost of wind power.

If a windfarm generates ten megawatts of power, it has extracted more than ten megawatts of energy from the environment. I’m sure it isn’t significant, not at the rate we do it, but what could be the cost of this load?
There has been talk of building huge offshore windfarms in some coastal areas. Could these have an effect on the weather maybe?

Have the ones in Palm Springs had any effect on the weather?

I’ve wondered about this myself.

In fact, I’ve wondered about hydroelectric power, too. But it seems to me that the water is going down no matter what, and that gravity is gravity, and that it’s not going to be diminished.

But wind, that affects the weather.

The potential for microclimate changes from wind farms has been endlessly debated. There may be some evidence of very small, very localized effects (inside the perimeter) but I don’t know of any macroclimate effects that have been substantiated. Wind farms are just a fraction of a pimple on the face of the earth. Any good-sized town has a far huger effect on weather patterns than the largest wind farm.

I don’t know, Cisco. There are also a lot of turbines (1000’s) at Altamont Pass, near Livermore CA.
I’ve read and heard a lot of discussion about the danger of these turbines to birds, but not a lot about any other effects.

I was not able to find the amount of energy entering the world’s atmosphere daily.
It is an astronomical amount from solar radiation.
All the wind & tide devices put together would be insignifigant in comparison.
I will keep looking for the data & post ASAP.

Hydroelectric power depends on dams with reservoirs, which tend to average water flow over the seasons. These dams have a dramatic effect on the downstream and upstream environments, and on the ecosystem in vast areas. But they are very efficient, power wise.

Tidal power is essentially applying regenerative braking on the rotation of the earth - in much the same way that a bicycle wheel slows down when you add a dynamo. Tidal power is slowing down the rotation of the planet. Probably insignificantly, and of course friction and viscosity of water passing through narrow channels ane doing a similar thing.

I’m a little confused. My impression was that the forces which produce tides (i.e. gravity) are slowing the Earth’s rotation as it is. Does tidal power increase this? I would have thought that since we’re exploiting the energy expended in producing the tides, tidal power would lessen the effect of tides, and hence slow the rotation less than tides alone.

I’m willing to believe that I’m way off base, though.

The soloar power reaching earth is on the order of 1.740×10^17 W.
In the overall scheme of things on this earth mankind is a pretty insignifigant organism exerting puny efforts to take advantage of winds and tides.
Fly cross country in a large jet at high altitude and you may begin to realize you are a tiny speck of near next to nothing in comparison to the magnitude and magnifigance of the earth itself!

Weather is chaotic system. If a butterfly in Spain can cause tornados in Kansas, what’s a buttload of wind turbines going to do? (And when are they going to kill that damn butterfly? :wink: )

I suppose the weather being chaotic, it simply may not be possible to predict what changes turbines will make.

Don’t need no stinkin’ airplane.
Us humans are, though, pretty significant in sustaining that which is important to our survival.

Some years ago, I read that hydroelectric power is speeding up the Earth’s rotation. The reasoning was that water is essentially being moved from it’s equilibrium distribution into reservoirs that are predominantly at temperature latitudes, thereby reducing the Earth’s moment of inertia and (by conservation of angular momentum) increasing its angular velocity. It’s exactly like how a figure skater speeds up her rotation by pulling her arms closer to her axis of rotation.

Of course, the effect is miniscule, but I thought it was neat.

how many miniscules make a megascule?
Yeah, I actually said that.

Tides are slowing earth’s rotational period because of tidal friction, which is mostly the friction of water moving around between high and low tides. Tidal power plants would increase that friction, and hence increase the rate at which earth’s rotational period is slowing. This makes sense if you think of where the energy from tidal power is coming - namely, the kinetic energy of the earth’s rotation. The tides just give you a way to tap into it, but that’s where the energy is being drawn from. If you’re sucking away at that energy, obviously the kinetic energy of the earth’s rotation has to decrease, and the only way it can do that is for the earth to rotate slower.

I wouldn’t worry too much about it, though. The rate of slowing is currently ~0.7 seconds per year. If my math is right, this means that days will lengthen to 25 hours in a mere 1.9 million years. If we somehow managed to install enough tidal power to double tidal friction (I doubt that’s possible without covering the entire ocean with the things) we’d have 25 hour days in just 950 thousand years. Horrors! I’m sure there are other far more significant environmental impacts of tidal power.

Interestign, I heard the opposite that it is slowing down the earth’s rotation by holding water far above the level water would seak naturally by damming it up.