An associate pointed out to me the existence of a YouTube presentation by
David Sadoway, in which he describes the invention of a new-type battery.
I replied as follows: James,
There are several ways to store electricity, in order to have a continuous supply when the initial generation is intermittent, such as only when the sun is shining or the wind is blowing.
All of these are storage devices or procedures by which the electricity can be recalled when needed.
The first is rechargeable batteries. It operates on the same basis as putting food in your refrigerator and periodically using it. When the supply runs down you restock the refrigerator.
Another is to use the electricity to electrolyze water into hydrogen and oxygen. You store the gases and when you need electricity, you reburn them in a fuel cell.
Another is to use the electricity to pump water to a higher elevation. When electricity is needed, the water is allowed to flow down through turbines to regenerate electricity. The second portion is well known as hydroelectric power from traditional reservoirs. However, the whole process is used in Chattanooga, Tennessee, where water is pumped to a reservoir on a mountaintop.
Another process is to use electricity to turn a huge flywheel. The moving flywheel can then generate electricity back. This is rather abstract and probably not very practical.
A lot of work is being done on rechargeable batteries, in view of the Obama Administration's interest in electric cars. There have been some good advances, and Sadoway's battery may be a significant achievement. Batteries have the advantage over the other processes in that they are considerably more portable. However, they may not be the most efficient for stationary power supplies, such as household electricity service. We will have to see how the technology develops with respect to economics. We must also remember that the standard process of generating a continuing supply of electricity from burning coal or natural gas in public utilities is presently more economical, as compared to solar and wind, which we have already pointed out has the disadvantage of unreliability.
I replied as follows: James,
There are several ways to store electricity, in order to have a continuous supply when the initial generation is intermittent, such as only when the sun is shining or the wind is blowing.
All of these are storage devices or procedures by which the electricity can be recalled when needed.
The first is rechargeable batteries. It operates on the same basis as putting food in your refrigerator and periodically using it. When the supply runs down you restock the refrigerator.
Another is to use the electricity to electrolyze water into hydrogen and oxygen. You store the gases and when you need electricity, you reburn them in a fuel cell.
Another is to use the electricity to pump water to a higher elevation. When electricity is needed, the water is allowed to flow down through turbines to regenerate electricity. The second portion is well known as hydroelectric power from traditional reservoirs. However, the whole process is used in Chattanooga, Tennessee, where water is pumped to a reservoir on a mountaintop.
Another process is to use electricity to turn a huge flywheel. The moving flywheel can then generate electricity back. This is rather abstract and probably not very practical.
A lot of work is being done on rechargeable batteries, in view of the Obama Administration's interest in electric cars. There have been some good advances, and Sadoway's battery may be a significant achievement. Batteries have the advantage over the other processes in that they are considerably more portable. However, they may not be the most efficient for stationary power supplies, such as household electricity service. We will have to see how the technology develops with respect to economics. We must also remember that the standard process of generating a continuing supply of electricity from burning coal or natural gas in public utilities is presently more economical, as compared to solar and wind, which we have already pointed out has the disadvantage of unreliability.
This is good. You’ve said lots of things that are right.
ReplyDeleteBut you can easily ruin your credibility by making one casual ignorant statement that is also not very imaginative.
There is a lot of work being done on flywheel and the concept is simple and the potential efficiency and longevity of flywheel systems can be very great.
Here is one example of flywheels being experimented with and used in hybrid power for cars.
http://www.extremetech.com/extreme/92794-kers-of-the-hybrid-car-flywheels-and-ultracapacitors-give-you-a-10-second-jolt
Here is a short article that describes flywheels as energy storage in spacecraft and satellites.
http://spaceresearch.nasa.gov/general_info/flywheel_lite.html
I apologize for not knowing as much about flywheels, as you think I should. However, it may be a bit harsh on your part to have accused me of using a "casual ignorant statement, which is not very imaginative"
ReplyDeleteI appreciate your sending me the two references, and I comment on each of these as follows:
http://www.extremetech.com/extreme/92794-kers-of-the-hybrid-car-flywheels-and-ultracapacitors-give-you-a-10-second-jolt.
This one says a lightweight flywheel will give a 5 to 20 second burst of power. If we stretch out the energy use, timewise, we might obtain one to two minutes of normal propulsion. It doesn't sound very effective for scale up to a large unit to equalize electricity supply from wind and solar.
http://spaceresearch.nasa.gov/general_info/flywheel_lite.html.
This one says that flywheels can compete with batteries in spacecraft primarily, because batteries have a shorter usable life. Notice also that the primary need is to cover the short 36-minute interval during which the spacecraft is in shadow, and solar energy is unavailable. Notice also that the bearing system requires use of magnets with the flywheel operating in a vacuum. For space operations, where a vacuum is the normal environment, this is ideal. Earth operation would require an extensive system for vacuum generation and containment.
Use of flywheels in subway trains may be a practical application for energy recovery from the braking system. This would apply also to automotive vehicles. However, it is an application unrelated to our original subject, which was the lack of continuity of solar and wind energy.
Both references involve use of flywheels in portable situations, and I do not dispute their applicability. However as mentioned above, the primary subject was the need for energy storage to cover times in the land-based electrical grid, when the primary electrical sources are solar or wind energy, and the sun is not shining, nor the wind blowing. The primary purpose of covering this "downtime", with batteries, flywheel, or other is to establish electrical supply continuity, which already exists in use of fossil fuel or nuclear power plants, and which supply electricity at costs less than solar and wind.
Not all processes or devices can be easily scaled up. For example, a flashlight or TV remote control has good applicability from power supplied by batteries. Conversely, we have yet to see a battery design which is applicable to handling "downtime" on the national power grid.
With respect to flywheels in a more basic sense, a flywheel must have mass and rotational velocity. The higher the mass, the less can be rotational velocity. The earth itself is a huge solar powered flywheel. It takes energy from the sun on the sunny side and rejects the energy to outer space on the shady side. It has only a small rotation of 1 per day, as compared to 60,000 RPM for manufactured flywheels. However, Earth's mass is tremendously larger than that of manufactured flywheels.
While using high rotational velocities can reduce the mass requirement, there is a limitation. Depending upon material quality, flywheels may disintegrate through centrifugal forces at higher velocities. If we are satisfied with low velocity, we would then need a very high mass for sufficient energy storage for a particular operation, such as an electrical grid. While I don't have any numbers, I'm sure calculations could be made, and I'm also sure that a flywheel would be impractical for the grid "downtime".