Most cost effective battery for large electric power storage? 4

[bob102939]

We assembled a 30kw generator for a friend for a machine shop and now looking for a way to better store energy. We have looked at lead acid but even making them from scratch will be very expensive. We are most open minded to designs that could be implemented and manufactured in house due to the very large amount of energy. IE, for 100K, I think we can justify learning and designing a system of making them if that can knock 50K out of the build cost.

Target storage might be 10Mwatts but we may have to reduce that number considerably to a more reasonable figure. Possibly only 1Mwatt.

 

[davidbeach]

Good luck. Very big companies are investing millions and not making much progress on this problem.

 

[MikeHalloran]

The math gets easier if you use the correct units, e.g. watt-hours or Joules for describing the size of your energy store, and watts, etc., for the rate at which you add to or deplete the store.



Mike Halloran
Pembroke Pines, FL, USA

 

[BJC]

Storing energy as diesel fuel is about as good as you can get right now.

 

[bob102939]

How does one store energy as diesel? Are you referring to the production of biodiesel? We have considered about everything including collection of grease for diesel production but the operating time/cost will be high and running a full time genset will not be a viable option. They only have a life span of maybe 20K hours max and extremely poor efficiency.

I have heard about molten sodium batteries as well as some Lion stuff but I have yet to price anything other than lead acid. I figure lead acid would look the cheapest on paper but still was ridiculous in price.

Hydro pumping will not be an option. We are as flat of a state as one can find...bummer... We do have wind though!!

 

[jghrist]

How does one store energy as diesel?

In a fuel tank. We don't mean to be facetious, but your OP didn't indicate what you had in mind for operating your 30 kW generator. If you were using a diesel engine, it would make no sense whatsoever to generate electricity, store it, and convert it for use later. Just generate when you need the electricity and store fuel until needed.

I guess from your last post that you are going to run the generator with an intermittent prime mover like wind or solar and need storage.

It still isn't clear why your friend needs a generator for his machine shop.

It doesn't help that you use terms like storing "10Mwatts" that make no sense technically.

 

[electricnewbie]

Here is an example 10 MW battery system you could build...

http://gigaom.com/cleantech/xtreme-power-a-super-battery-for-hawaiian-wind-farms/

It may be a little pricey for a machine shop.. all you need is a $117 million dollar DOE loan.

 

[desrod]

Bob,
you never stated your requirement or what was the problem.

A 30 kW diesel running for 8hr adds up to 240 kW-h.
We mentioned that you might need 10 000 kw-h of energy storage? Is that correct?

Where are you? Where is the installation? In North America, you should expect 1-2 outage per year for a maximum duration of 3 hr in the worst case.

Wind or Photo Voltaic combined with smaller storage might be a viable solution for you.
Daniel

 

[bob102939]

Ahhh!! I very much apologize. 30kw WIND generator... They already have a 3ph power service but there is a joint effort to run the shop off grid for other reasons. The generator has proven very effective in a grid tie configuration but they now would like to be able to say "off the grid".

The obvious problem here is wind is not reliable but here in the midwest, it is a certainty at some point. Our estimates show realistically if we can supply total battery power for 10 working days or 2 weeks total, they should be ok.

In looking at the draw at the shop, there is an average draw of 25-45kw/h during business hours, then that drops down to only 2kw/h off peak. Obviously there could be no exact science in this because we cannot bet on the wind. I also realize batteries have many variables that determines how much you can get from them.

I was not implying to use a diesel genset to "make" diesel or anything of that matter. We were simply looking for mass storage for all this wind power... The power is not the problem, just storing it presents a real issue.

 

[davidbeach]

just storing it presents a real issue

Yep, no kidding. Lead-acid is probably your best bang for the buck but you'll need very deep pockets. If you've got an underground cavern of some type handy that can be sealed, then compressed air storage might work for you. I think the shop will be on the grid for a good while to come.

 

[alehman]

A similar question appeared here thread658-286355

As I mentioned, technologies such as sodium-sulfur (NGK, GE) and nano-structure lithium-ion (A123, Exergonix) are making progress in storage density and cost, but are still expensive. Large-scale batteries appear to be in the range of $300 to $400 per kWh.

An interesting study -

http://prod.sandia.gov/techlib/access-control.cgi/2006/066740.pdf

Alan
“The engineer's first problem in any design situation is to discover what the problem really is.” Unk.

 

[ScottyUK]

Is it deja vu or was this same thread around a month or two ago?

Pumped storage hydro is your friend for utility-level energy storage. Fairly high capital investment, and needs a mountain. And lots of water.


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If we learn from our mistakes I'm getting a great education!

 

[jghrist]

You may also find that your 30 kW wind generator is an induction machine that will not generate power when not connected to the grid.