Wind-energy creating energy glut in Europe, utiilities are PAYING CONSUMERS to keep lights on

[SMR 368]

If you can find a way to store all the excess energy, which is, unfortunately, a draw back for both wind and solar, requiring some sort of back-up energy source. Some sort of potential energy storage is probably the answer, like flywheels, for instance.

This was a great post until you mentioned flywheels. Do you really think that is a good way to store energy? Unfortunately, friction says no.

[I AM NOT THAT GUY 5,715]

This was a great post until you mentioned flywheels. Do you really think that is a good way to store energy? Unfortunately, friction says no.

What friction? Ever heard of bearings? Anyways, flywheels are used in industry all the time to store energy slowly that is needed to be delivered quickly, such as in punches and shears. Even your car uses a flywheel to store energy.

[PhiLandShiR 18]

What friction? Ever heard of bearings? Anyways, flywheels are used in industry all the time to store energy slowly that is needed to be delivered quickly, such as in punches and shears. Even your car uses a flywheel to store energy.

A flywheel in a vaccuum chamber using magnetic bearings would be almost perfect I would think....

[SMR 368]

What friction? Ever heard of bearings? Anyways, flywheels are used in industry all the time to store energy slowly that is needed to be delivered quickly, such as in punches and shears. Even your car uses a flywheel to store energy.

Bearings have friction. Less, yes, but it's still there.

There is a big difference between the amount of energy required to operate a punch or a car and the amount of energy required to be a significant portion of the electricity consumption of even a small area. In any case, flywheels are not used for punches because of their efficiency as energy storage. They are used to provide a sort of charge and release function where energy is collected in the flywheel and then released all at once. The driving factor is not efficiency but rather the ability to deliver a lot of force quickly that is stored more slowly.

A flywheel in a vaccuum chamber using magnetic bearings would be almost perfect I would think....

But how are you going to maintain the vacuum or get magnets powerful enough to hold a flywheel large enough to make a difference?

The main problem with the flywheel approach is that it simply has a disconnect with the scope of power distribution. In order to store even 1 Megawatt-hour, you would need a flywheel 20 meters in diameter that weighs 13 metric tonnes (with the weight all on the perimeter of the flywheel to simplify calculations), rotating at a dizzying speed of 1000 rpm. And a megawatt hour is hardly a dent in power generation. A large city consumes thousands of megawatts, so we're talking a small fraction of the energy that a city uses in an hour.

The energy stored goes up as the square of the rotational speed and proportional to the weight of the flywheel as long as it is stored in the perimeter of the wheel. But friction also increase dramatically as speed increases.

I think you would have much better success solving this problem by investing in transmission infrastructure. We don't have surplus power everywhere. If we could get it where we need it, the problem would be solved. Building more power lines is much more efficient and cost effective than gigantic fly wheels would be.

[ScottThuy 140]

There is always a loss of some energy when we try to store energy... the loss due tofriction could be small compared to other alternatives...

The pumping water to use as a hydraulic storage method is a great idea.... its a shame we could not come up with a similar concept pumping seawater to an inland basin and if there were that much leftover energy it could be used to desalinate some of the salt water...

[I AM NOT THAT GUY 5,715]

I have seen a lot of designs for storing kinetic energy as potential energy. Besides flywheels, there are accumulators to store liquids under pressure, and another possibility was using long vertical mine shafts. If you think friction is too big a culprit to allow you to store the energy long enough, you can always build the thing in space, and beam the energy back and forth using microwaves, or just build the solar array in space period.

For earth bound systems, if the flywheel is big enough, then air friction would be less of a factor in relation to the mass. A lot depends just how long you have to store the energy. I have seen flywheel prototype vehicles that could hold a usable charge for hours.

I am thinking that storage dams and pumping may not be feasible in many areas, for instance California, where water use and land use are in constant competition among the various users, environmental concerns set aside. Hydroelectric plants have already been closed down in may area for concerns over the impact to Coho Salmon.

Edited April 26, 2010 by ##########

[I AM NOT THAT GUY 5,715]

Bearings have friction. Less, yes, but it's still there.

There is a big difference between the amount of energy required to operate a punch or a car and the amount of energy required to be a significant portion of the electricity consumption of even a small area. In any case, flywheels are not used for punches because of their efficiency as energy storage. They are used to provide a sort of charge and release function where energy is collected in the flywheel and then released all at once. The driving factor is not efficiency but rather the ability to deliver a lot of force quickly that is stored more slowly.

But how are you going to maintain the vacuum or get magnets powerful enough to hold a flywheel large enough to make a difference?

The main problem with the flywheel approach is that it simply has a disconnect with the scope of power distribution. In order to store even 1 Megawatt-hour, you would need a flywheel 20 meters in diameter that weighs 13 metric tonnes (with the weight all on the perimeter of the flywheel to simplify calculations), rotating at a dizzying speed of 1000 rpm. And a megawatt hour is hardly a dent in power generation. A large city consumes thousands of megawatts, so we're talking a small fraction of the energy that a city uses in an hour.

The energy stored goes up as the square of the rotational speed and proportional to the weight of the flywheel as long as it is stored in the perimeter of the wheel. But friction also increase dramatically as speed increases.

I think you would have much better success solving this problem by investing in transmission infrastructure. We don't have surplus power everywhere. If we could get it where we need it, the problem would be solved. Building more power lines is much more efficient and cost effective than gigantic fly wheels would be.

Thanks for doing the math. I get too lazy to whip out the calculator.

Edited April 26, 2010 by ##########

[Darnell 8,478]

I dunno, if there's more power in a certain area, it would behoove the local Chamber of Commerce to make serious pitches to get new industry into the area, in some form of tax credits or relocation assistance. Go Green ! use less miles of wires !

Edited April 26, 2010 by Darnell