What about a national battery?

That is, a battery that could supply the nation's electrical needs for a few days during a blackout.

The author computes it could be done with a sufficiently large, or sufficiently numerous, lead-acid batteries. The whole shebang would need only 5 billion tons of lead. The US has 7 million tons of lead reserves, while the entire world has approximately 80 million tons.

We'd better get busy looking for more. Chinese toys might be a good place to start...

(Caution: Real maths in use)

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Reply to
HeyBub
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"HeyBub" wrote in news:vridnTqXKKTwrFvTnZ2dnUVZ snipped-for-privacy@earthlink.com:

Somewhere I read that the battle between DC and AC is being revived. DC should be better at withstanding weather related interruptions, so fewer (big) power outages at the transmission line and transformer(?) levels. Don't ask me about the physics ... I don't think that a branch falling down on an AC line and breaking it is any different from a DC line, but apparently it would be easier and cheaper to bury DC lines than AC lines.

Reply to
Han

For one thing, you wouldn't have a single "national" battery.

You would have many regional batteries located in more strategic locations with access to major grid tie-in points. The north-american grid system is not wired to be able to handle energy input from a single location.

And it wouldn't use lead-acid batteries. It would use molten sodium batteries.

It's already been done in Texas as a way to compensate for needing to upgrade a transmission line to a small town (Presidio). It would have been more expensive to string a new transmission line capable of supplying the town with electricity during peak use, so what they are doing instead is storing power in the battery during non-peak time and then drawing power from it during peak time.

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Presidio, Texas, a border town of under 5,000 people in the Rio Grande Valley, recently had a 4 megawatt battery installed by Electric Transmission Texas to improve service. It cost $25 million and was bigger than a house.

The Big Ol? Battery (BOB) is dwarfed by Fairbanks? Battery Energy Storage System (BESS), installed by ABB Group in 2003. BESS can hold a charge of 26 Megawatts for up to 15 minutes and is used to back up the local grid.

The two batteries are quite different. BOB uses sodium and sulfur. BESS is nickel-cadmium.

But what Don Sadoway of MIT has discovered is that if your metal is molten, it can hold a lot more power in a lot less space. Sadoway says his battery costs less than lithium, and holds a charge for a longer period of time. A battery the size of a shipping container would carry 1 megawatt for several hours.

The design is relatively simple. Melted magnesium at the top, melted antimony at the bottom, and a salt composed of both elements in the middle. The salt breaks down as the battery is charged, then rebuilds as electrons are discharged.

Sadoway, who recently turned 60, said his inspiration was the way aluminum is coaxed from bauxite by being melted using electricity. For his birthday he?s getting a symposium in his honor this June. Sadoway is a University of Toronto alumnus. (Go True Blue.)

While the Sadoway battery is impressive, it really illustrates how far research must travel to make a smart grid a reality.

Renewable power is not reliable ? clouds obscure the sun, and sometimes the wind doesn?t blow. Power demand also fluctuates. Better, more powerful, and cheaper batteries are needed to match supply with demand.

Sadoway?s battery is one small step down a long, long road. It?s an interesting technique, but it?s probably not our final answer.

Reply to
Home Guy

Read the article. The author pointed that out. His "National Battery" was in the aggregate.

Again, read the article. The author chose lead-acid for his example because:

A. Lead is the cheapest B. Efficient (85% in a charge cycle) C. Well-tested technology (over 150 years of use and development) D. Lead is common E. Lead-acid batteries are, by far, the most common option in power storage devices

Reply to
HeyBub

On 11/18/2011 6:36 AM, Han wrote: ...

Any weather-related issues are only a side-effect--the underlying reason for DC over AC for transmission is cutting the AC losses.

It's now a possibility that wasn't practical before the advent of solid-state electronics that could be made to handle the necessary voltages/currents.

Manitoba Hydro has been an early implementor...

Siemens has been building transmission lines in China and India, last I knew there were plans on east coast in US w/ PEPCo altho I haven't followed progress. Anything like offshore wind will rely on them to get large amounts of power back to shore.

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Reply to
dpb

It's only $$$$...and the protesters who raise barriers against accomplishing anything anymore.

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Reply to
dpb

On 11/18/2011 4:20 AM, HeyBub wrote: ...

Or all that lead paint had to be good for something besides hazardous landfill material/employment.

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Reply to
dpb

Read my article.

Any such large-scale battery would not use lead-acid.

There are two such large-scale batteries in use. One uses NiCad, the other uses molten sodium.

Here's why we'll never see a "national battery" using lead-acid technology:

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There is simply not enough lead in the world to meet the baseline design goal (power the country for 1 week). Even if this is scaled back to 1 day, it would require about 700 million tons of lead. There are about

80 million tons of lead in known world reserves.

See also:

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Reply to
Home Guy

Limitations on sources.

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Reply to
dpb

This is a great exercise in math but virtually all blackouts are in the distribution system, not in the generation system. If you can't get the power from the generators to the consumer, you can't get the power from a battery to the consumer.

Reply to
gfretwell

"HeyBub" wrote in news:xIOdnW1YJ5xx-VvTnZ2dnUVZ snipped-for-privacy@earthlink.com:

Sorry, I haven't read the article. Nevertheless, below ...

There must be a reason that lithium batteries are most often used for systems large (cars) and small (laptops, camera batteries). Isn't high current charge and discharge one of those reasons?

Reply to
Han

Size and weight

Reply to
krw

" snipped-for-privacy@att.bizzzzzzzzzzzz" wrote in news: snipped-for-privacy@4ax.com:

Of course, Li is quite a bit lighter than Pb ...

Reply to
Han

Don't need batteries -- use a spinning flywheel connected to a motor/generator for the energy storage. Then all you need is mass. Make the flywheel out of steel or even concrete or stone. Make lots of them, put them everywhere and you have a simple, low cost energy storage system with unlimited capacity.

Tomsic

Reply to
Tomsic

The traditional storage method is pumped water. You fill up a lake at the top of the hill and run it through a turbine when you want the energy back. The advantage is, rainfall gives you free energy.

Reply to
gfretwell

snipped-for-privacy@aol.com wrote in news: snipped-for-privacy@4ax.com:

I believe there are a few of those pumped storage hydroelectric systems

The enormous losses during pumping and regeneration seem to make this very inefficient but apparently the differences between off-peak and peak rates can make it economical. Not relly useful for individuals or small coomunities, I'd think. The flywheel seems practical, but of course the amounts of energy stored may make the system rather dangerous when (not if) it malfunctions. I've seen the damage when ultracentrifuges go poof, and that was really very little mass.

Reply to
Han

On 11/18/2011 12:13 PM, hr(bob) snipped-for-privacy@att.net wrote: ...

High voltage overhead lines aren't insulated anyways, and that's the only place where DC transmission lines are used (or are likely to be used in the foreseeable future). There may be a few very special cases where a HV line will be buried, but that's not the target for what is going to help much at all on end-user reliability.

The transmission line losses are certainly nothing at all alike between the two; that's the whole reason for doing it in the first place.

I've not heard of anybody proposing low voltage transmission nor distribution lines as DC...

The little transformers aren't a big part of the problem; it's the high voltage rectifiers need to convert _TO_ DC for transmission that were the hangup until solid-state developed to the point they were possible that way for modern HV transmission to be practical via DC.

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Reply to
dpb

I'm thinking sabotage could be pretty ugly, too.

nate

Reply to
N8N

Actually, it's (1/2) mass * velocity squared.

True, but that "squared" term matters.

I'd like to see a citation for that.

Reply to
krw

Good memory. I remembered the Swiss flywheel buses too and that's why I posted the flywheel idea. The buses were described many years ago -- in Popular Science Magazine, I think. Google "Flywheel buses"; there are some references listed.

Tomsic

Reply to
Tomsic

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