Storing wind energy 1

[SomptingGuy]

http://www.globalnewenergynetwork.org/news.php?news_id=2190696

Can anyone shine more light on this?

It looks quite simple the way it's described: excess power created by the turbine is used to pump out the vessel against (big) hydrostatic pressure. Power is returned by reversing the process.

But what's left in the vessel as it's pumped out? A vacuum (which would boil off the remaining sea water), air from some breather pipe? Other?

- Steve

 

[BigInch]

Turn them into artificial reefs?

Independent events are seldomly independent.

 

[davefitz]

I think that underground compressed air storage would work best during times of low elec demand and high wind power production. The compressed air could be used later during times of high power demand/ low wind production by a gas turbine, whose output and efficiency would be greatly increased if it had access to a reservoir of compressed air.

Another concept proposed by some engineers from holland about 10 yrs ago was to construct an artifical offshore island ,with a deep basin in the middle, with wind turbines around the circumference of the island. During times of low wind power but high demand the ocean would be permitted to rush into the empty basin and produce power thur hydro turbines, and during times of excess wind power and low demand the water would be pumped out of the basin.

Yet another concept would be to have a high energy consuming industry operate only during times of excess wind power- examples may be re-melt of recycled metal, or production of some chemicals.

"Nobody expects the Spanish Inquisition! "

 

[cranky108]

Now you are talking smart grid. However the orignal concept of smart grid is to reduce residentual demand for industry uses. AKA, shut off your home airconditioner during the hotest part of the day so some industry can make cheep plastic (humm, chairs, bottles, or smart phones).

Why not just make electricity pricing follow the availibilty. The price can convey the value, or difficulty to generate. Wind power at night should be priced lower than other power during the day. But I guess that is why they are trying to store it.

How about ice storage. If it melts, it cools the building it was intended to cool anyway.

 

[ornerynorsk]

Seems like a Rube Goldberg operation to me. My opinion only. I think fuel cells (thinking of Bloom boxes) hold much more commercial potential in the future, especially that methane can be produced from bio sources. Getting creative with energy conservation, as opposed to greater alternative capacity, as others have mentioned, will give a far greater return-on-investment. This is an area that is lagging behind R&D, even though it's far easier to implement (perhaps not in changing people's habits, though)

Or we could always go back to coal fired steam plants.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[cranky108]

What ever happend with coal gassification, followed by burning it in a combined cycle plant?

Don't get me wrong, we do need power at night. You know for the street light that shines in my window, and the cell phone chargers left plugged in, and the kids night light.
But that energy should be priced to the demand.

Yea, I know electric cars will change all of that, just look at the numbers of units sold.

My point is if you are going to store energy, do it in a way that some of the waste losses can also be used.

Why not just use the wind machine to compress air directly, and get rid of the generator/motor losses. You can then create a distribution system for the compressed air to all the service stations in a large town.

 

[berkshire]

cranky,
Or you could just use a Tata Automobile, if they ever build them.

http://www.gizmag.com/tata-motors-air-car-mdi/22447/

B.E.

You are judged not by what you know, but by what you can do.

 

[davefitz]

cranky 108:
coal gasification makes sense if the energy price of coal is less than half the energy price of natural gas- that may be true in europe , but certainly will not be true in the USA for the next 100 yrs. The combination of very high investment cost plus lower overal availability plus low shale gas cost implies that it will not be viable in the US. There is now being built in Odessa texas a trigeneration gasifier, where hydrogen and pure CO2 are also sold as a product together with the electricity from the IGGG.

Also, integrating the gas fired combined cycle plant with the gasifier should only be considered if you also provide a backup connection to the interstate natural gas pipeline- an IGCC without such an interconnect is doomed to very plant low availability.It only takes one piece of critical equipment to shut the entire plant down, including gasifier, CTG, STG, cryogenic air separation plant,material handling system.

"Nobody expects the Spanish Inquisition! "

 

[cranky108]

I understand the hydrogen with nitrogen usage to make NH4, so the hydrogen generation makes since, although I might not have thought about it.

The CO2 is probally used for well injection to increase oil production, which also makes since.

CO2 can also be used for feeding some aquitic plants for oil harvesting to make bio-jet fuel.

However on wind machines, if you are including compressed air as a storage medium, it might be better to have part of the energy extracting capacity for electricty, and part as compressed air, thus limiting the sizing of both. It is doubtful the units will run at full capacity, and having the ability of both allows switching production for the grid, or storage. And if you ever have full wind, you can do both.

My recollections of some wind machines is they have four generators placed around the inside of the hub, so just replace two of them with air compressors, and use clutches select which ones are operating.

 

[TomDOT]

cranky - don't think about it on a per-nacelle basis, think about it on a per-farm basis. You only connect the [storage technology] to some fraction of the turbines. Simpler that way.

 

[cranky108]

Well it would be easer to replace two of the generators with compressors, and use the large volume of the tower as a compressed air tank. It would intergrate the storage into each tower.

 

[davefitz]

CAES compressed air energy storage is best applied in conjunction with gas turbines and an underground salt cavern ( for compressed air storage). During times of excess free electricity the compressor part of the gas tubine would be used store air at high pressure in the underground cavern. During times of electricity shortage the stored compressed air would be bled into the combustor of the gas turbine and the power produced by a gas turbine which does not need to use its compressor is 2-3 times the electrical output that would result if it did need to use its compressor.

Storage of compressed air abovegorund in a large tank is extraordinarily dangerous. Also, the only way to manufacture such a large tank onsite would be using the chinese style spiral wound ligaments, multile layers in thickness.

Other strategies to construcitvely use excess free electricity include hydrogen production ( from electrolysis of H2O), batch operation of smelters, batch operation of chemical plants ( eg, sodium hydroxide, otehr energy intensive chemicals). The dutch have proposed builiding a hollow island with wind turbines at teh circumference and pumped hydro storage at the island interior.

"Whom the gods would destroy, they first make mad "

 

[cranky108]

Maybe so, but I seem to recall the auto shop using air tools to remove my tires, so I know it is possible without a GT.

So explain to me why it won't work?

 

[dcasto]

Does anyone have any idea as to the pressures needed to store compressed air. It's way more than a gas tubing can generate

 

[berkshire]

The domain name for the link expired, I hate when that happens.
So you are looking at pumped storage. The only reason for that, is to keep the value of the generated product up, instead of letting it go to waste.
It does not matter what the efficiency is, because if you are successful at storing, anything, you can resell it.
The primary issue is capital cost.
B.E.

You are judged not by what you know, but by what you can do.

 

[cranky108]

The value of stored energy, if assuming 50% loss in storage, is 150% of the orginal cost to generate it. My point is you would have to increase the size of the wind farm to accomidate the losses, and bear the added cost of the added capital. This may come out as energy costing about 150 to 200+% of the energy from a simple no storage system.

So my question is, why wants to pay that much for windless wind stored energy?

However in the case of hydrogen storage, the fuel can be used for transportation, which electricty is more difficult to use.

 

[davefitz]

In the limit case where the underground UG reservoir is very large and is leak tight, then the optimum pressure for air storage is the same as the design outplet pressure of the CTG's compressor. If the CTG has a 10:1 pressure ratio for its compressor, then the UG reservoir should be held at 9-10 bar. There may be a 3% pressure drop from the compressor to UG reservoir, and another 3% pressure loss when flowing the air back to the turbine. Those assumptions allow the use of standard CTG components, except for the electrical generator and shaft bearings, since the net electric power generated with the compressor uncoupled may be 2-3 times the net electric power generated with the compressor coupled to the turbine.

In real life the UG reservoir is not of infinite volume, and some leakage is expected.

"Whom the gods would destroy, they first make mad "

 

[PurchasingEngineer]

I am located in Michigan, and we have a large hydrostatic (pumped -hydro) energy storage facilities in Ludington. You can read more about it here:

http://www.consumersenergy.com/content.aspx?id=6985

If you'd like, I can put you in contact with someone who may direct you to the appropriate person at consumers energy who can provide further information.

I am from the power industry, and from where I sit, these ponds seem to work extremely well. The trouble is, there are environmental concerns, and they are hard to get built these days as a result.

 

[berkshire]

The yards creek pumped storage station is still in operation. I believe it is now over 50 years old.

http://www.pseg.com/family/power/fossil/stations/yardscreek.jsp

B.E.

You are judged not by what you know, but by what you can do.

 

[ornerynorsk]

Use the excess windpower to compress and/or liquefy NG.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[davefitz]

pumped energy storage using hydro from mountain top reservoirs is currently used on a schedule deteremined by the hedge meisters based on the low cost of electricity ( due to low demand or excess wind capacity) and released thru the hydroelectic turbine generators at a time when the bid price for power is at a maximum. This is an example classic monetary feedback being used to optimize the distribution of resources, and the same model can be used for other means of equalizing demand vs generation.

If sufficient pricing signals are provided to the congnizant consumer, then the consumers will modify their behavior to also equalize demand vs generation. Large industrial consumers of power can be considered as cognizant , and the previously suggested concepts of liquifying gas to LNG, or batch production of energy intensive chemicals ( sodium hydroxide, H2 , etc) will likely follow.

"Whom the gods would destroy, they first make mad "